PUBLIC HEALTH BULLETIN 
No. 295 
MANUAL OF RECOMMENDED PRACTICE 
FOR SANITARY CONTROL OF THE SHELLFISH INDUSTRY 
RECOMMENDED BY THE 
UNITED STATES PUBLIC HEALTH SERVICE 
1946 
FEDERAL SECURITY AGENCY 
U. S. Public Health Service 
WASHINGTON 25, D. C. FEDERAL SECURITY AGENCY 
United States Public Health Service 
THOMAS PARRAN, Surgeon General 
SANITARY ENGINEERING DIVISION 
J. K. HOSKINS 
Assistant Surgeon General 
Chief of Division PUBLIC HEALTH BULLETIN No. 295 
MANUAL OF RECOMMENDED PRACTICE 
FOR SANITARY CONTROL OF THE SHELLFISH INDUSTRY 
RECOMMENDED BY THE 
UNITED STATES PUBLIC HEALTH SERVICE 
1946 
PREPARED BY DIRECTION OF THE SURGEON GENERAL 
UNITED STATES 
GOVERNMENT PRINTING OFFICE 
WASHINGTON : 1946 
For sale by the Superintendent of Documents, U. S. Government Printing Office 
Washington 25, D. C.—Price 15 cents CONTENTS 
Page No. 
Introduction 1 
General Administrative Procedure 1 
1. Definitions 2 
1.1 Sketch Illustrating Kinds of Shellfish Areas 4a 
2. Growing Areas 4 
2.1 Surveys i.' 4 
2.2 Classification of Shellfish Areas 5 
2.3 Approved Shellfish Areas 5 
2.4 Grossly Polluted Closed Areas ". . 6 
2.5 Moderately Polluted—Restricted Areas ; 7 
2.6 Hibernation (Oysters) 7 
2.7 Re-laying 8 
2.8 Policing of Closed Areas 9 
2.9 Depletion of Closed Areas '.... 10 
3. Harvesting and Handling 10 
3.1 Boats 10 
3.2 Disposal of Body Excretions 10 
3.3 Procedure to be Employed in the Bacteriological Examination of Shell- 
fish and Shellfish Waters 11 
3.4 Table—Comparison of Coliform Organism Scores with Most Probable 
Number of Coliform Organisms per 100 Milliliter 12 
3.5 Examination of Mussels and Clams for Presence of Poison 12 
4. Preparing for Market—Processing 13 
4.1 Conditioning 14 
4.2 Cleansing 14 
4.3 Floating and Wet Storage 16 
4.4 Dry Storage 17 
Shucking and Packing Plant: 
4.5 Plant Arrangement 17 
4.6 Floors 18 
4.7 Walls and Ceilings 18 
4.8 Screening 19 
4.9 Light 19 
4.10 Heating and Ventilation 20 
4.11 Toilet Facilities 20 
4.12 Handwashing Facilities 21 
4.13 Water Supply 21 
4.14 Personnel 22 
4.15 Supervision 23 
Shucking Room: 
4.16 Shucking Benches and Stands 23 
4.17 Pails 24 
4.18 Knives and Blocks 25 
4.19 Aprons and Finger Cots 25 
4.20 Cleaning 25 
4.21 Bactericidal Treatment 26 
4.22 Other Bactericides 27 Page No. 
4.23 Cabinets with Auxiliary Steam Boilers 28 
4.24 Hot Water Sterilization 28 
4.25 Storage of Equipment 28 
4.26 Shell Disposal 28 
4.27 Miscellaneous 29 
Packing and Shipping Room: 
4.28 Equipment (Utensils, skimmers, blowers, etc.) 30 
4.29 Shipping Containers 31 
4.30 Refrigeration Facilities 32 
4.31 Ice 33 
4.32 Bactericidal Treatment Facilities 33 
4.33 Clothing and Aprons 34 
4.34 Cleaning (Utensils and Building) 34 
4.35 Bactericidal Treatment 35 
4.36 Equipment Storage 35 
4.37 Packing Shucked Stock 36 
4.38 Repacking Shucked Stock 37 
4.39 Packing and Shipping Shell Stock 37 
4.40 Identification of Shell Stock on the Market 38 
4.41 Records 38 
Index 40 INTRODUCTION 
In 1925, State and local health authorities and the shellfish producers 
requested the Public Health Service to exercise supervision over the sani- 
tary quality of shellfish shipped in interstate commerce. In conformance 
with this request, a system of endorsement of State control measures, was 
developed whereby each shellfish-producing State presents a list of certified 
dealers which it has determined conforms to State requirements. Such 
lists, if the State control measures are acceptable to the Public Health 
Service, are published periodically for the information of consumer States. 
To establish the degree of State control deemed essential, the Public Health 
Service prepared the “Minimum Requirements for Endorsement of State 
Shellfish Control Measures and Certifications for Shippers in Interstate 
Commerce.”* 
As a development of these Minimum Requirements, the present manual 
has been prepared to enumerate more specifically the items of sanitation 
which should be observed. Certain inspection forms and rating sheets 
may be used to determine as precisely as possible the degree of compliance 
attained with Public Health Service requirements in each producing State. 
GENERAL ADMINISTRATIVE PROCEDURE 
In carrying out this cooperative control the State, the industry, and the 
Public Health Service are each responsible for certain procedures. These 
procedures are in general as follows: 
The State shellfish regulatory authorities promulgate the requirements 
which must be met by the industry. The industry carries out the State re- 
quirements. The Public Health Service evaluates the extent of com- 
pliance with its own requirements and expresses its opinion regarding the 
adequacy of compliance upon which will be based its endorsement or with- 
holding of endorsement of State control measures. 
1. Procedures to be followed by the State. 
(a) The State adopts adequate laws and regulations for the sanitary 
control of the shellfish industry. 
(b) The State shellfish regulatory authority makes the necessary in- 
spections, sanitary and bacteriological surveys of the growing areas, in- 
dicates areas from which shellfish may be marketed, the contaminated 
areas from which market shellfish may not be taken, and patrols its 
restricted areas. 
(c) The State shellfish regulatory authority inspects each shellfish plant 
periodically. It is intended that the State be guided by this manual in the 
making of such inspections and in evaluating the results thereof. 
1 2 
(d) The State shellfish regulatory authority issues numbered certifi- 
cates to producers and dealers handling shellfish entering interstate com- 
merce after it has been determined that the shellfish conform to State 
requirements. 
(e) The State shellfish regulatory authority makes all State records and 
information pertaining to its sanitary control of the shellfish industry 
available to the Public Health Service. 
2. Procedures to be followed by the Industry. 
(a) Holders of State certificates place the number of the certificate on 
each package of their shellfish shipped in interstate commerce. 
(b) All interstate shippers of shellfish keep records of all interstate ship- 
ments in such detail as to facilitate quick tracing of any particular shipment 
to the point of origin. Such records are made available for inspection at 
reasonable hours by representatives of the State regulatory authority and of 
the Public Health Service, 
3. Procedures to be followed by the Public Health Service. 
(a) The Public Health Service inspects and rates a representative num- 
ber of shucking and packing plants annually in each State, cooperates 
with the States in making sanitary and bacteriological surveys of growing 
areas, or makes such surveys independently by agreement with the State 
regulatory authorities. The entire State control procedure and machinery 
for sanitary control of shellfish are examined and rated annually by the 
Public Health Service. 
(b) The Public Health Service publishes and keeps current a list of 
interstate shippers of shellfish certified by each shellfish-producing State 
for the information of health authorities and others concerned in shellfish- 
consuming States. 
1. DEFINITIONS 
The following definitions shall apply in the interpretation of this 
manual: 
And/or.—Where this term is used, “and” shall apply where possible, 
otherwise “or” shall apply. 
Area, growing.—Growing area is any area in which market shellfish or 
seed shellfish are growing. (Sec. 2, p. 4.) 
Areas, approved.—Areas which, after examination as required in 2.3, 
p. 5 of this manual are approved. 
Areas, grossly polluted, closed.—Areas from which the taking of shell- 
fish for market purposes is not permitted. (Sec. 2.4, p. 6.) 3 
Areas, moderately polluted, restricted.—Areas which are intermediate 
between approved and grossly polluted areas as regards exposure to and 
protection against fecal pollution. 
Cleansing,—Cleansing is the artificial process of removing from shell- 
fish such contamination as they have acquired while growing in moderately 
polluted growing areas. (Sec. 4.2, p. 14.) 
Coliform organisms.:—Wherever the term “coliform organisms,” “coli- 
form group,” or “coliform bacteria” occurs, such term shall be considered 
to include all of the organisms which upon transfer from a positive pre- 
sumptive test (as positive in lactose broth) show fermentation with gas 
formation in lactose medium containing 0.00133 percent brilliant green 
and 2.0 percent of bile (brilliant green lactose bile broth). 
Conditioning.—Conditioning is that process which permits market shell- 
fish to free themselves of retained sand, grit, and/or silt under controlled 
conditions. (Sec. 4.1, p. 14.) 
Depletion.—Depletion is the complete removal of all growing shellfish 
from the area in question. (Sec. 2.9, p. 10.) 
Floating.—Floating consists of holding market-size shellfish on struc- 
tures of wood or other material supported by pontoons or piling in shallow 
bodies of water near shore. No rigid definition of what is near shore seems 
practicable. 
Near shore.—Generally speaking, areas within a thousand feet of mean 
low water mark should be considered as being near shore. Cultivation of 
shellfish on trays supported on piling, near shore or in lagoons surrounded 
by dikes connected to the shore or in shallow areas near shore shall be 
considered as being in the same category, as far as risks to the public health 
are concerned, as the practice of floating, and shall be subjected to the same, 
or equally rigid, restrictions. (Sec. 4.3, p. 16.) 
Re-laying.—Re-laying is that process which involves the removal of 
market shellfish from any of the three classes of growing areas to other 
growing areas to improve their quality of growth or both. (Sec. 2.7, p. 8.) 
Repacking.—Repacking is the packing of shucked shellfish in plants 
other than those in which they have been shucked. 
Shellfish.—Shellfish means all fresh and frozen oysters, clams, and 
mussels, either shucked or in the shell, and any fresh edible products 
thereof. 
Shellfish, market.—Market shellfish are those shellfish which are har- 
vested and/or prepared for sale to the consumer. 
Shellfish, seed.—Seed shellfish are those shellfish which are harvested 
for use by the gatherer or for sale to a shellfish planter or grower to be 
laid down again in growing areas for further growth and cultivation. 4 
Shellfish, shucked.—Shucked shellfish are those shellfish which have 
been removed from their shells. 
Shell stock.—Shell stock are shellfish which remain in their shells. 
Storage, dry.—Dry storage is the storage of market shell stock out of 
water. (Sec. 4.4, p. 17.) 
Storage, wet.—Wet storage is the storage in water of shellfish intended 
to be marketed within three months, whether the storage be in natural 
bodies of water or in tanks containing sea water. (Sec. 4.3, p. 16.) 
Transplanting.—Transplanting is the process which involves the re- 
moval of seed shellfish from one area to another area. 
Water shallow.—Water less than five feet deep at low tide. 
2. GROWING AREAS 
2.1 Surveys.—All shellfish growing areas in any State shall have been 
examined by sanitary and bacteriological surveys, prior to the approval 
of interstate shipments of shellfish from such areas. 
Public Health Reason: Shellfish grow in bodies of salt water receiving 
fresh water run-off. Frequently, the rivers or smaller streams entering 
shellfish growing areas carry contamination which may either have been 
washed into them from the land areas drained by such rivers, streams, or 
tributaries, or may have been conveyed into them through artificial struc- 
tures such as drains, canals, or sewers. Many times they receive sewage 
originating in cities, towns, villages, or isolated houses. Unless careful 
surveys, supplemented by bacteriological examinations of the water are 
made to ascertain whether areas from which shellfish are shipped to mar- 
ket are at times exposed to serious contamination of human origin, 
such shellfish may become a medium through which disease may be con- 
veyed. Periodic bacteriological examination of samples of water does 
not take the place of sanitary surveys but is an integral part of such 
surveys. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: A thorough examination of the watershed tributary to the 
shellfish growing area has been made by technically trained persons com- 
petent to evaluate the probable effect upon the shellfish growing area of 
the discharge of sewage into tributary streams taking into account the 
following factors: 
(1) The quantity of pollution from all sources, including sewage of 
domestic origin. 
(2) The degree of treatment (if any) given the sewage before being 
discharged, particularly as concerns the probable destruction of pathogenic 
organisms. 
(3) The degree of dilution of the sewage with clean water. SOURCE OF POLLUTION 
CLOSED AREA 
GROSSLY POLLUTED 
RESTRICTED AREA 
MODERATELY POLLUTED 
APPROVED AREA 
Figure 1— Sketch shozving classification of shellfish growing areas 5 
(4) The relative freshness of sewage discharges as determined by the 
lapse of time between such discharges and their arrival in the shellfish area. 
(5) The opportunities afforded for natural self-purification of the area. 
(6) The bacteriological examinations of water samples collected from 
predetermined stations in the area on different days sufficient to give a 
bacteriological picture of the water under various stages of tide and under 
varying weather conditions.1 
2.2 Classification of Shellfish Areas.—All shellfish growing areas in any 
State shall be classified as approved or restricted. Restricted areas may 
be further subdivided and designated as either moderately polluted or 
grossly polluted. In order to confirm or modify tentative classifications 
based on the sanitary survey, moderately polluted shellfish growing areas 
should be examined rather intensively for the presence and density of coli- 
form organisms, particularly in those portions of the areas bordering on 
the approved areas. Only occasional bacteriological samples are necessary 
from areas which the sanitary survey indicates are obviously free from 
pollution or are grossly polluted. 
Public Health Reason: The probable presence or absence of pathogenic 
organisms in shellfish waters and therefore the probable contamination of 
shellfish contained in such waters is of the greatest importance in deciding 
whether or not shellfish obtained from such areas may be marketed directly 
without submitting them to further treatment or whether the shellfish ob- 
tained from such areas should be subjected to purification or cleansing 
processes before granting permission to market them. There is no practi- 
cable process on which to base judgment regarding the probable freedom 
of such areas from the presence of pathogenic organisms other than by 
making a careful inventory of all the actual and potential sources of pollu- 
tion which might affect the area, carefully weighing the probability that 
natural purification will protect shellfish areas and testing any conclusions 
thus reached by a series of bacteriological examinations of samples of 
water to determine the most probable number of coliform bacteria present 
(organisms associated with sewage pollution). 
2.3 Approved Shellfish Areas.—-Approved shellfish areas shall satisfy 
the following conditions: 
The sanitary survey shall disclose no likelihood that human fecal dis- 
lln making the bacteriological survey the number of samples examined from 
each station should be sufficient to give a true picture of the number of coliform 
organisims present in the water under the various tides and weather conditions 
occurring during the shellfish harvesting period. 
The minimum number will vary with the various areas and the purpose for which 
the examinations are made. Where examinations are made to define the line 
between approved and restricted areas it is believed that a record of at least 15 
samples per station in the critical area is necessary. 6 
charges reach the area in dangerous concentrations or before sufficient 
time has elapsed to render such discharges innocuous. 
The median bacteriological content of samples of water collected from 
those portions of the area determined by sanitary survey to be most prob- 
ably exposed to fecal contamination shall not show the presence of organ- 
isms of the coliform group in excess of 70 per 100 ml. of water expressed 
in terms of most probable numbers (MPN) in a series of samples from 
each station sufficient to determine the conditions existing. These samples 
shall have been collected throughout the suspected area during one or 
more active shellfish seasons during which* conditions as disclosed by the 
sanitary survey shall have remained practically unchanged. The samples 
shall have been collected under various stages of tide and with due con- 
sideration to varying weather conditions. 
Bacteriological re-examinations of the area must be made whenever 
periodical sanitary surveys, made not less than once every 2 years, 
indicate that there may have been a significant increase in the quan- 
tity of sewage entering the area since the last bacteriological examinations 
were made. 
Permanent sampling stations shall be located on a chart of the area 
showing principal hydrographic and topographic data. (Charts of the U. S. 
Coast and Geodetic Survey should be used whenever they are available for 
the area under consideration.) 
The spacing of the sampling stations shall take into consideration the 
shellfish areas, the depth of water at low tide, and the prox- 
imity of probable sources of pollution. A larger number of samples shall 
be taken in that portion of the area bordering on the moderately polluted 
area than in that portion of the area bordering on areas free from pollu- 
tion. In order to establish a line between an approved area and a 
moderately polluted area, sampling points should ordinarily be spaced 
no further apart than approximately 1,000 feet in any direction. 
In such bacteriological surveys a proportional number of samples 
should be collected under various tidal conditions, and with heavy rainfall 
and dry weather run-offs, to obtain an adequate picture of the possible 
pollution of the area. 
2.4 Grossly Polluted Closed Areas.—If the sanitary survey discloses 
that the area is either obviously subject to gross pollution by direct dis- 
charge of sewage and other wastes, or demonstrably exposed more or less 
continuously to even slight direct contamination with human fecal dis- 
charges from nearby sources ashore, or if an area usually of good quality, is 
exposed to occasional direct and immediate contamination with human 
fecal discharges, or if bacteriological examinations indicate that the degree 
of contamination is greater than that tolerated for moderately polluted 7 
areas, then such area may be declared to be a grossly polluted area from 
which the taking of shellfish for market purposes shall not be permitted. 
2.5 Moderately Polluted Restricted Areas.—After making sanitary and 
bacteriological surveys as described in Sec. 2.1, p. 4, the area may be de- 
clared to be a moderately polluted restricted area if it is shown that: 
(1) The area is intermediate between approved and grossly polluted 
areas as regards exposure to and protection against fecal pollution. 
(2) The bacteriological survey discloses that the median bacteriological 
content of the water expressed in terms of the most probable number 
(MPN) of coliform organisms per 100 ml. lies between 70 and 700. 
(3) The sanitary survey shows that such contamination is probably 
of human origin. 
When an area has been classified as a moderately polluted restricted 
area bacteriological re-examination of the water in that portion of the 
area adjacent to the grossly polluted area shall be made at least every 
year if a partial sanitary resurvey indicates that an increase in contamina- 
tion may have taken place. Partial sanitary resurveys consisting at least 
of a review of maps, office records, or data regarding significant changes 
in population, sewerage systems, sewage treatment facilities, or of other 
factors which might tend to cause an increase in the pollution of the 
area shall be made at least yearly. Complete sanitary surveys shall be 
made whenever the State regulatory authority issuing interstate shippers 
certificates deems such survey to be necessary. Information obtained 
from such surveys shall be made available to the Surgeon General of the 
United States Public Health Service whenever data on a particular area 
are desired. (A decision as to whether any given areas in this class may 
be used for the taking of shellfish, and if so, under what conditions should 
be based, in each instance, upon a careful and thorough study of the 
area which would take into account all factors which might affect the 
decision, namely; the findings on sanitary survey and on bacteriological 
examinations of the water. Sec. 2.1, p. 4.) 
2.6 Hibernation (Oysters). —Under written permission from and under 
strict control by the State regulatory authority subject to the following 
restrictions, oysters may be taken for market purposes from moderately 
polluted areas during the period that the oyster is in hibernation. 
The taking of oysters will be permitted only during the period when 
the temperature of the water remains consistently at or below 41° F. and 
permission will not be given by the State regulatory authority until it 
has determined that the coliform content of the oysters does not exceed 
20 per 100 ml. expressed as MPN. 
Public Health Reason: It is recognized that the oyster enters a state 
of hibernation during periods when the temperature of the water over- 8 
lying the growing area is 41° F. or less and that while in that state is 
relatively free of bacteria of the coliform group. 
Satisfactory Compliance: This item shall be deemed to have been satis- 
fied if: 
(1) Written permission to take oysters from a specified area is issued 
by the State regulatory authority. 
(2) The taking of oysters from the area be limited to the period when 
the overlying water remains consistently at or below 41° F. 
(3) No oysters are taken for market purposes until bacteriological 
examination shows a coliform content of 20 or less per 100 ml. expressed 
as MPN. 
(4) The State regulatory authority maintains a strict control over the 
operations. 
2.7 Re-laying.—Shellfish may be re-laid from one approved growing 
area to another approved area at any time. Shellfish may be re-laid from 
a polluted area to an approved area only under such restrictions as will 
not permit polluted shellfish to reach the consumer. 
Public Health Reason: Shellfish from approved growing areas should 
'not jeopardize the public health if they find their way to the market 
during the re-laying process. On the other hand, those from polluted 
areas may cause illness and death if they are sold after removal from 
the polluted grounds and before having been re-laid in approved areas 
for self-cleansing purposes. They must be held in approved areas for 
a sufficient length of time at a water temperature above 50° F. to accom- 
plish self-cleansing. Below this temperature self-cleansing proceeds too 
slowly to make it effective. To eliminate the health hazard involved in 
re-laying, it is necessary to regulate the movement of shellfish from 
polluted to clean areas by means of suitable restrictions. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
(1) Written permission is given by the State agency having juris- 
diction to the person desiring to take shellfish from a polluted area, and 
if notification of such permission is given to all other interested State 
agencies. 
(2) Such permission is given only to responsible persons, said respon- 
sibility having been determined by the past record of the permit receiver. 
(3) Taking of shellfish from polluted areas and laying them in 
approved areas is under the close supervision of the State agency having 
jurisdiction over shellfish sanitation. 
(4) Shellfish taken from polluted areas and re-laid in approved areas 
are held in the approved areas for a period of at least 14 consecutive days, 
during which period the temperature of the water is constantly above 
50° F. 9 
(5) Shellfish re-laid during the marketing season in approved areas 
from polluted areas are not taken from the approved areas for market 
purposes until permission to do so has been received in writing from 
the State agency having authority over shellfish sanitation. 
2.8 Policing of Closed Areas.—All shellfish areas which have been 
closed as the result of unsatisfactory findings following sanitary or bac- 
teriological surveys shall be posted, warning the public that the shellfish 
are unsafe for human consumption and shall not be removed except for 
re-laying or transplanting. Notice shall also state the penalty to be im- 
posed on those convicted of removing shellfish illegally from these areas. 
Closed areas shall be patrolled by the agency of the State government 
possessing authority at frequent intervals to make certain that no shellfish 
are removed illegally. This section shall apply both to areas used for the 
production of seed as well as to areas used for the production of market 
shellfish. 
Public Health Reason: Because every effort made by the shellfish 
authorities to see that shellfish are produced and marketed under proper 
sanitary conditions may be defeated unless shellfish from closed areas are 
excluded from market, it becomes important that necessary steps to ex- 
clude unsafe shellfish be taken. This may be accomplished by adequately 
advertising and/or posting and policing closed areas, and by the rigid 
enforcement of appropriate laws. There is no sharp line of demarcation 
between large-sized seed shellfish and small-sized market shellfish, hence 
it is necessary to control operations pertaining to both classes of shellfish 
by means of certain safeguards. 
Satisfactory Compliance: This item shall be deemed to have been satis- 
fied if shellfish are not taken from closed areas illegally. 
In the absence of direct evidence that shellfish have been taken illegally 
from closed areas, the following items may be used as criteria in judging 
the effectiveness of measures taken: 
(1) If the boundaries of closed areas containing shellfish are con- 
spicuously marked by fixed objects (preferably located ashore) which 
are easily visible from any point inside the closed area. 
(2) If printed copies of the description of closed areas are supplied to 
persons licensed to take shellfish in the vicinity of such closed areas or if 
such copies are furnished without charge to any bona fide shellfish digger, 
tonger, dredge operator, or other interested persons requesting such 
description. 
(3) If the closed areas are under periodic and effective patrol by the 
State department having jurisdiction, due consideration being given to sur- 
prise visits made at night. 
(4) If record data showing designated closed areas and their relation- 10 
ship to patrol activities and violations discovered are maintained in the 
central office of the State supervisory agency. 
2.9 Depletion of Closed Areas.—ln some cases it may be more economi- 
cal to deplete a closed shellfish area than to attempt patrol. When this is 
undertaken all shellfish of market size and as many of smaller size as can 
be gathered by reasonable methods shall be removed from the areas under 
direct supervision of the State regulatory authority. A similar depletion 
of the area shall be carried out at approximately 2-year intervals. 
Public Health Reason: Complete removal of shellfish from polluted 
areas to clean areas, under appropriate precautions, is the best safeguard 
against unsafe shellfish reaching the market and producing illness in 
consumers. 
Satisfactory Compliance: This item shall be deemed to have been satis- 
fied if: 
(1) In the absence of effective patrolling the removal of shellfish from 
closed areas is effected within 2 years of the date of adoption of this 
manual; marketable shellfish are removed from the closed areas every 2 
years thereafter, and 
(2) The removal operations are carried out by a State agency or under 
the direct supervision of a State agency. 
3. HARVESTING AND HANDLING 
3.1 Boats.—All boats used for tonging, dredging, or transporting shell- 
fish (including “buy” boats), shall be so constructed, operated, and main- 
tained as to prevent contamination of the shellfish in the boat. 
Public Health Reason: Precautions exercised in gathering shellfish 
from approved growing areas may be nullified by contamination from 
bilge water in the boat, by leakage or washing of contaminated water into 
the boat or over the sides when the boat is in areas subject to contamina- 
tion. 
Satisfactory Compliance: This item shall be deemed to have been satis- 
fied if; 
(1) Perforated platforms or storage bins are so constructed and located 
as to prevent bilge water or overboard polluted water from coming into 
contact with the shellfish. 
(2) All water used for boat cleansing comes from unpolluted sources. 
3.2 Disposal of Body Excretions.—During the marketing season no 
body excretions shall be discharged overboard from a boat used in harvest- 
ing shellfish while it is in areas from which shellfish are being dredged, 
tonged, or otherwise gathered. Such boats shall be provided with a water- 
tight metal container, having a close-fitting metal cover, for reception of 
body excretions. The container shall be securely fastened to prevent spill- 11 
ing. The contents of the container shall be disposed of by discharging into 
suitable sewage disposal units on shore or by discharging overboard in 
areas designated for this purpose by the State health authorities, or by 
burying, or by burning, after which the container shall be thoroughly 
cleaned before being returned to the boat. 
Public Health Reason: Since gastrointestinal infections are at times 
conveyed by raw shellfish, it is highly important to protect the shellfish 
on boats and in shellfish growing areas, as well as areas adjacent thereto, 
from infection with such organisms as are known to be conveyed through 
excretions of the human body. 
Satisfactory Compliance: This item shall be deemed to have been satis- 
fied if: 
(1) A boat which is away from shore toilet facilities more than 3 
hours has thereon a watertight container made of heavy-gage metal, with 
a tight-fitting cover, of sufficient capacity to provide for the crew but in no 
case less than 2-gallon capacity. 
(2) The container is securely fastened to the boat to avoid spilling and 
in such a position as to be at the maximum distance from shellfish on board. 
(3) There is evidence that the container is used for the purpose pro- 
vided for. 
(4) The contents of the container are properly disposed of by dis- 
charging overboard into a designated area or carried to shore for disposal 
into a sewerage system or a sanitary privy, or are buried or incinerated. 
(5) The container is thoroughly cleansed after the contents have been 
removed and before the container is returned to the boat. 
3.3 Procedure to be Employed in the Bacteriological Examination of 
Shellfish and Shellfish Waters.—The procedures to be followed are those 
given in the Report of the American Public Health Association Standard 
Methods Committee to the Committee on Research and Standards, Jour- 
nal of the American Public Health Association, vol. 33, No. 5, May 1943, 
pp. 582-91. The report is entitled “Recommended Method of Procedure 
for Bacteriological Examination of Shellfish and Shellfish Waters.” 
(Copies are available from the American Public Health Association, 1790 
Broadway, New York, N. Y., for 25 cents per copy.) 
These procedures include those for bacteriological examination of shell- 
fish growing waters and for bacteriological examination of shellfish. The 
interpretation and application of results of the bacteriological examination 
of shellfish growing waters have been set forth in 2.3, 2.4, 2.5, pp. 5, 6, 7 
of this manual. 
Until more data are available, any attempt to interpret the results of 
bacteriological examinations of shellfish other than oysters as taken from 
growing areas or cleansing processes in terms of their probable freedom 12 
from pathogenic organisms is questionable. For the time being, the chief 
reliance should be placed on the quality of the water over the growing 
areas or that used in cleansing processes. It seems reasonable to assume, 
however, that an MPN value of 2,400 or more coliform organisms per 
100 ml. occurring in successive samples of shellfish, other than oysters, as 
taken from the growing area, at point of shucking or after cleansing should 
be interpreted as an indication of unfavorable conditions or practices 
surrounding the production and handling of the product and should 
necessitate investigation and further control activities on the part of the 
regulatory agency. 
The following applies to the interpretation and application of results 
obtained from the bacteriological examination of oysters only: 
When an MPN value of 230 or more of coliform organisms per 100 ml. 
of sample persists in oyster shell stock sampled at the growing areas or 
in shell stock or shucked oysters at the point of shucking, it should be inter- 
preted as an indication of unfavorable conditions or practices surrounding 
the production and handling of the product and should necessitate investi- 
gation and improved control measures on the part of the supervisory 
agency, providing that in occasional samples, an MPN value of 2,400 coli- 
form organisms per 100 ml. may be tolerated in some samples. If this 
occurs in more than 2 consecutive samples, corrective measures shall be 
enforced by the regulatory authority. 
3.4 Comparison of Coliform Organism Scores with Most Probable 
Number of Coliform Organisms Per 100 Milliliter.— 
Score 
MPN 
Score 
MPN 
1 
20 
41 
1,300 
2 
45 
50 
2,400 
3 
78 
140 
3,500 
4 
130 
230 
5,400 
5 
230 
320 
9,200 
14 
330 
410 
16,000 
23 
490 
500 
24,000 
32 
790 
1,400 
35,000 
3.5 Examination of Mussels and Clams for Presence of Poison.—A 
representative number of samples of mussels and clams shall be collected 
from growing areas suspected of containing poisonous shellfish and shall 
be examined for the presence of poison before mussels and clams in- 
tended for human consumption are taken from such growing areas. 
Public Health Reason: Numerous cases of mussel poisoning and some 
deaths have occurred, especially on the Pacific Coast, from eating poisoned 
mussels. Research has indicated that the poison may be present in both 13 
mussels and clams and has been associated with the presence of the dino- 
flagellate gonyaulax catenella in the water in which the shellfish grow. A 
method has been devised for detecting and quantitatively estimating the 
poison in shellfish but no specific treatment has been found for the 
poisoning. 
Satisfactory Compliance: This item shall be deemed to have been satis- 
fied if: 
Representative samples of shellfish from growing areas are collected 
and examined for the presence of toxic substances whenever their occur- 
rence is suspected or deemed possible. The need for making this test can 
be judged after experience by the presence in the overlying water of the 
dinoflagellates associated with mussel poisoning by the season of the 
year, and by other considerations such as reported poisonings among 
consumers or handlers of shellfish. 
4. PREPARING FOR MARKET—PROCESSING 
4.1 Conditioning.—Conditioning of shellfish from approved growing 
areas as defined in Sec. 2.3, p, 5, shall be permitted only in watertight 
tanks, adequately protected against introduction of contamination from 
adjacent or connected spaces or surfaces. The water used shall have a 
salinity equal to that of the water from which the shellfish are taken and 
shall, after treatment, meet the bacteriological requirements of the Public 
Health Service Drinking Water Standards, (This pamphlet, Public 
Health Reprint No. 2697 can be obtained from the Superintendent of 
Documents, Washington, D. C., price 10 cents). 
Public Health Reason: Conditioning in natural bodies of water subject 
to all noncontrollable influences surrounding such natural conditions has 
been found to introduce so many possibilities of contamination as to 
jeopardize the quality of the shellfish undergoing conditioning processes. 
Numerous instances in which the conditioning of shellfish in natural bodies 
of water has been responsible for the spreading of illness are on record. 
Therefore, if conditioning is practiced, it shall be done in watertight tanks 
where the quality of the water can be rigidly controlled. (For de- 
tails of methods which have been successfully applied in conditioning and 
cleansing of shellfish in England and America, reference is made to “Report 
on Mussel Purification,” by R. W. Dodgson, in the Ministry of Agricul- 
ture and Fisheries, Fishery Investigations, Series 11, vol. X, No. 1, 
London, and the “Report of the Shellfish Committee,” American Public 
Health Association Year Book, 1936-37, pp. 180-196. 
Satisfactory Compliance: This item shall be deemed to have been satis- 
fied if: 
(1) The tank is watertight and has relatively smooth inside surfaces 
to permit adequate cleansing; so located that the bottom of the tank is at 14 
least 1 foot above the extreme high water mark of the water body 
adjacenf to it, and the tops of the sidewalls are at least 4 inches above the 
level of the contiguous floor or ground surface. 
(2) Floor or ground surfaces adjacent to the tank slope away from it 
to permit effective and complete drainage. 
(3) Water for the process is obtained from a natural body of water, 
the quality of which, when treated, is equal to or better than that specified 
for growing areas. 
(4) Applied water is maintained in such condition by the continuous 
or intermittent application of chlorine to it that the chlorine residual does 
not fall below 0.05 p.p.m. 
(5) Water used for conditioning on entering the tank is; 
free from objectionable settleable solids; 
of a salinity at least equal to that to which the shellfish are 
accustomed, such salinity to be determined by the use of a 
hydrometer; 
of a bacteriological quality at least equal to that for drinking water; 
carrying a chlorine residual of not less than 0.5 p.p.m. as deter- 
mined by the orthotolidine test 15 minutes after the chlorine 
application, or determined by some equivalent test. 
(6) The fill-and-draw tank is emptied at least once every 24 hours or if 
a continuous-flow tank receives applied water at a rate that will fill it in 
not more than 24 hours. 
(7) The oxygen content of the cleansing water at all points in the tank 
is maintained at not less than 30-percent saturation. 
(8) The plant operator is experienced in this type of work or possesses 
a satisfactory knowledge of the principles of water treatment and bac- 
teriology and satisfies the State health department that he is fully capable 
of operating the plant concerned. 
(9) Plant employees possess at least the physical qualifications outlined 
for a shucker in Sec. 4.14, p. 22. 
(10) Unauthorized persons as well as animals are excluded from the 
plant. 
(11) Boots to be worn by an employee while working in a condition- 
ing tank are used for this purpose only and are washed in chlorinated 
water containing at least 50 p.p.m. chlorine before the employee enters the 
tank. 
(12) Suitable operating reports are submitted at least monthly to the 
controlling State agency. 
4.2 Cleansing: Shellfish for artificial cleansing shall be taken only 
from clean or moderately polluted growing areas as defined in Sec. 2.5, 
p. 7. Artificial cleansing shall be permitted only in watertight tanks ade- 15 
quately protected against the introduction of contamination from adjacent 
or connected spaces or surfaces. The water used shall have a salinity equal 
to that of the water from which the shellfish are taken and shall meet 
the requirements of the Public Health Service Drinking Water Standards. 
Adequate precautions shall be taken to prevent shellfish intended for 
cleansing from reaching the market before cleansing has been completed. 
Public Health Reason: Artificial purification of moderately polluted 
shellfish has been proven to be successful if adequately and thoroughly 
performed. (See reference, bottom p. 6.) Experience has shown that 
some shellfish from polluted areas, due to inadequate policing, may reach 
the market. The cleansing process provides a safe outlet for some shell- 
fish from moderately polluted growing areas and thereby reduces the 
volume of unsafe shellfish surreptitiously gathered and offered for sale 
through circuitous channels. 
Satisfactory Compliance: This item shall be deemed to have been satis- 
fied if: 
(1) The tank is watertight and has smooth inside surfaces to permit 
adequate cleansing; so located that the bottom of the tank is at least 1 
foot above the extreme high water mark of the water body adjacent to 
them, and the tops of the sidewalls at least 4 inches above the level of 
the contiguous floor or ground surface. 
(2) Floor or ground surfaces adjacent to the tank slope away from 
it to permit effective and complete drainage. 
(3) Water for the process is obtained from a natural body of water, 
the quality of which is equal to or better than that specified for approved 
growing areas and after treatment meets the same requirements as speci- 
fied for the water used in conditioning. (Sec. 4.1, p. 14.) 
(4) Applied water is maintained in such condition by the continuous 
or intermittent application of chlorine to it that the chlorine residual does 
not fall below 0.05 p.p.m. 
(5) The oxygen content of the cleansing water at all points in the 
tank is maintained at not less than 30 percent saturation. 
(6) Only live clean-washed shellfish, having a coliform content of 
less than 24,000 per 100 ml. expressed as MPN, and the shells of which 
are sufficiently whole to permit their retention of shell liquor are sub- 
mitted to the process, and adequate precautions are taken to prevent 
shellfish intended for cleansing from reaching the market before cleansing 
is completed. 
(7) Shellfish are treated for a period of not less than 24 hours in 
water having a temperature above 50° F. 
(8) The results of tests for each batch of oysters cleansed give MPN 
coliform concentrations of not more than 230 per 100 ml. and for each 16 
batch of soft clams cleansed an MPN coliform concentration of less than 
2,400 per 100 ml. when subjected to a 24-hour presumptive test described 
in Sec. 3.3, p. 11. 
(9) No treated shellfish are released for consumption without author- 
ity of a plant operator approved or licensed by the State regulatory 
authority. 
(10) The plant operator is experienced in this type of work, or pos- 
sesses a satisfactory knowledge of the principles of water treatment and 
bacteriology, and has been approved by the State health authorities. 
(11) Unauthorized persons, animals, and rodents are excluded from 
the plant. 
(12) Plant employees possess at least the physical qualifications out- 
lined for a shucker in Sec. 4.14, p. 22. 
4.3 Floating and Wet Storage.—Floating and wet storage as defined in 
Definitions, pp. 3 and 4, shall not be practiced unless written 
approval is given each year by the State regulatory authority. This 
approval is to include, whenever floating is involved, a sketch drawn to 
scale, showing on the reverse side of the interstate shipper’s certificate 
issued to the interstate shipper, the fixed location of the float or structures 
and all the potential hazards to which shellfish floated in the designated 
area may be exposed. The statement shall also describe the measures 
taken to protect the shellfish from the above potential hazards. Similar 
sketches and descriptions shall be appended to certificates of shippers 
marketing shellfish cultivated near shore. The presence of usable floats 
in the water shall be deemed to be evidence that floating is being practiced. 
Public Health Reason: Removal of shellfish from growing beds to 
artificial floats usually anchored close to shore and habitations and fre- 
quently in shallow water for convenience, subjects an accumulated quan- 
tity of shellfish usually deposited in an abnormal number of layers, to 
concentrations of pollution which may constantly or intermittently reach 
the floats and to which the shellfish are not subjected in growing areas 
as described in Sec. 2.1, p. 4. Shellfish on floats anchored over approved 
growing areas are more directly exposed to chance contamination from 
boats than are shellfish stored in the growing areas themselves, since 
it is customary to “float” the shellfish near the surface where fresh sewage 
is apt to be found in greatest concentration. Shellfish on floats are 
therefore protected to a less degree by dilution than are shellfish on 
bottom areas. Experience has demonstrated that floats are seldom per- 
manently moored or secured over clean natural growing areas, but may 
be moved sooner or later to protected coves, harbors, or shallow areas 
to prevent their destruction in stormy weather or to docks and piers for 
easier access. 17 
Satisfactory Compliance: This item shall be deemed to have been satis- 
fied if: 
(1) Floating is practiced only in strict compliance with the terms of 
the written approval of the State regulatory authority. This approval is to 
include a sketch drawn to scale on the reverse side of the certificate 
issued to the interstate shipper, showing the fixed location of the float 
or structures, the potential hazards to which shellfish floated in the desig- 
nated area may be exposed, and a statement describing the measures 
taken to protect the shellfish from the above potential hazards. This 
written approval shall be valid for not longer than 12 months. 
(2) Similar sketches and descriptions, as provided in the paragraph 
above shall be appended to Interstate Shippers Certificates marketing 
shellfish cultivated near shore. 
4.4 Dry Storage.—Shell stock in dry storage shall be adequately pro- 
tected from contamination at all times. 
Public Health Reason: If shell stock is stored in a place where ground 
or surface water or drainage from floors, bilges, and equipment can 
accumulate, contamination carried by such water or drainage may con- 
taminate the shell stock. Shellfish may be contaminated also by domestic 
animals and rodents if they are not excluded. 
Satisfactory Compliance: This item shall be deemed to have been satis- 
fied if: 
(1) Floor of storage room is constructed of an impervious material 
free from cracks, holes, ruts, or other uneven surfaces that interfere 
with proper cleaning or drainage, and is graded to assure complete and 
rapid drainage. 
(2) Storage area is protected from flooding. 
(3) Walls are smooth and of material which will not deteriorate under 
repeated washings. 
(4) Storage area contains no material or equipment not pertaining 
to storage of shellfish. 
(5) Bins, hoppers, sacks, barrels, or other containers fully protect 
the stored shellfish from contamination. 
(6) There is found no evidence of animals, rodents, and unauthorized 
persons having access to the plant. 
Shucking and Packing Plant 
4.5 Plant Arrangement.—Unless shellfish are shucked directly into 
packing containers with no further processing, the shucking and packing 
processes shall be done in separate rooms. There shall be installed in the 
partition between the two rooms a delivery window, through which the 
shucked stock is passed to the packing room. 18 
Provision should be made for storing the employees outer, garments, 
aprons, gloves, etc., in a separate room or rooms, or in lockers. 
Public Health Reason: The nature of the shucking operation is such 
that the shuckers’ clothing becomes very soiled. If shuckers enter the 
packing room, shucked stock, cans, and other equipment may become con- 
taminated. Rooms or lockers are provided for clothing, aprons, and gloves 
to eliminate the tendency to store such articles on the shucking benches 
or in packing rooms, which interferes with the shucking and packing opera- 
tions and the cleaning activities. 
Satisfactory Compliance: This item shall be deemed to have been satis- 
fied if: 
(1) Shucking and packing operations are carried on in separate rooms 
unless shellfish are shucked directly into packing cans with no further 
processing. 
(2) Shuckers do not go into or through the packing room for any pur- 
pose. 
(3) The delivery window is provided with a suitable slide or door and 
the shelf is of smooth metal, concrete, or tile, draining toward the shucking 
room and curbed on the packing room side if necessary. 
(4) Well-maintained rooms or lockers are provided for storing cloth- 
ing, aprons, and gloves of employees. 
4.6 Floors.—The floors shall be constructed of concrete or other im- 
pervious material; graded to drain quickly; free from cracks or uneven 
surfaces that interfere with proper cleaning or drainage; and maintained 
in good condition. 
Public Health Reason: Properly graded floors of durable, impervious 
material such as concrete, maintained in good condition, promote rapid 
disposal of liquid and solid wastes, are easily cleansed and the floor is more 
apt to be kept in a clean and sanitary condition. 
Satisfactory Compliance: This item shall be deemed to have been satis- 
fied if the floor is: 
(1) Of impervious material. 
(2) Graded so that the drainage is complete and rapid. 
(3) Free from holes, cracks, ruts, or other uneven surface. 
4.7 Walls and Ceiling.—The walls shall be smooth, washable, and light 
colored. The ceiling, if provided, and the roof shall be tight to prevent 
entrance of dirt or other foreign material. 
Public Health Reason: Light-colored and properly finished walls and 
ceiling encourage cleanliness and are more easily cleaned. A tight ceiling 
and roof reduce the possibility of dirt or- other foreign material reaching 
the product, especially during inclement weather. 
Satisfactory Compliance: This item shall be deemed to have been satis- 
fied if: 19 
(1) The walls are of smooth concrete or impervious material, or 
smooth painted wood which will not deteriorate under washing and flush- 
ing and are maintained in good condition. 
(2) The ceiling, if provided, and roof are tight. 
4.8 Screening.—During seasons when insects, especially house flies, 
are on the wing, space used for washing and packing shucked shellfish shall 
have all openings effectively screened, including outward-opening, self- 
closing doors, unless other effective means are provided to prevent the en- 
trance of flies. 
Public Health Reason: The habits and characteristics of flies are such 
that they may become an important factor in the spread of intestinal disease 
if flies are allowed to come in contact with shucked shellfish. 
Satisfactory Compliance: This item shall be deemed to have been satis- 
fied if: 
(1) All openings are effectively covered with screening approved by 
the state regulatory authority whenever flies are evident. Broken, 
torn, or poorly fitted screens shall not be accepted as satisfactory com- 
pliance. 
(2) Outer screen doors open outward and are self-closing. Exclusion 
of flies can be made more effective when screen doors open outward and 
are provided with closing devices, such as spring hinge, pulley and weight, 
coil spring, or similar device. 
(3) Other effective means are provided to prevent the entrance of flies 
and if, at the same time. 
(4) No flies are present in the packing room. 
4.9 Light.—Ample light to work by shall be provided in all working 
rooms. When necessary, natural light shall be supplemented with artificial 
light. » 
Public Health Reason: Adequate light encourages cleanliness of work- 
ing rooms and shucking processes. 
Satisfactory Compliance: This item shall be deemed to have been satis- 
fied if: 
(1) Existing State regulations governing lighting are complied with or 
in the absence of such regulations light of an intensity of not less than 
5 foot-candles is maintained on all working surfaces when workers are at 
their working positions. 
(2) Windows or other openings, if depended upon for illumination, 
have an aggregate area of not less than one-tenth of the total floor area and 
are so arranged as to insure proper light distribution. 
(3) All windows and skylights are kept cl^an. 
(4) Artificial light is provided wherever shucking and packing are 
practiced at night or on dark days. 20 
4.10 Heating and Ventilation.—Working rooms shall be heated when 
necessary and ventilated so that workers may operate with safety and effi- 
ciency and without impairing their health. 
Public Health Reason: If sufficient heat is not provided the efficiency 
of the operators is affected and may result in practices which impair the 
sanitary quality of the shellfish. 
Inadequate ventilation or overcrowding promotes the spread of respira- 
tory infections among employees. 
Satisfactory Compliance: This item shall be deemed to have been satis- 
fied if: 
(1) A comfortable working temperature is maintained. 
(2) Ventilation is provided sufficient to eliminate odors and discomfort. 
(3) At least 10 square feet of floor space is provided for each shucker. 
4.11 Toilet Facilities.— shellfish shucking house shall be provided 
with separate sanitary toilets for each sex, conveniently located, but not 
opening directly into any packing or shucking room. Such tpilets shall be 
constructed according to local and State requirements and at least equal to 
rural sewage disposal recommendations of the Joint Committee on Rural 
Sanitation (Rural Sewage Disposal—Recommendations of Joint Commit- 
tee on Rural Sanitation—Reprint No. 2461 from the Public Health Re- 
ports, 1943, 32 pages. Can be obtained from the Superintendent of Docu- 
ments, Washington 25, D. C.). Toilets shall be properly operated and 
maintained, so that the waste is inaccessible to flies and does not pollute 
the surface soil or contaminate any water supply. Separate toilet facilities 
for each sex shall not be required where family shucking is carried on and 
satisfactory toilet facilities are available for family use in the home or con- 
veniently located nearby. 
Public Health Reason: The.organisms of typhoid fever, dysentery, and 
of other diseases are present in the body wastes of persons sick with such 
diseases. In the case of typhoid fever, well persons (carriers) may dis- 
charge the organisms in their body wastes. If a toilet is not flytight and 
so constructed as to prevent overflow, infection may be carried from the 
excreta to the shucked shellfish by flies or through the pollution of the 
water supply used in processing the shellfish or the water in which the 
shellfish are grown. 
Satisfactory Compliance: This item shall be deemed to have been satis- 
fied if: 
(1) There are separate flush toilets for each sex, conveniently located 
in the plant, the wastes from which are disposed of in a manner satis- 
factory to the State health authorities. (The requirement of separate 
toilets for each sex does not apply in the case of a family shucking plant 
located in the immediate vicinity of a home providing satisfactory 
toilet facilities.) 21 
(2) The toilets do not open directly into the shucking or packing room. 
(3) The toilets are constructed, operated, and maintained in accordance 
with plans and instructions of the local and State authorities. 
(4) At least 1 water closet and 1 urinal are provided for every 30 
male employees and at least 1 water closet is provided for every 20 
female employees. 
(5) A pit privy, chemical toilet, or other type of privy is provided, 
constructed, and operated in accordance with plans and instructions of the 
State board of health in those States permitting the use of these types of 
toilets. 
(6) There is no evidence of human defecation or urination about the 
shucking house premises except in the toilets provided for these purposes. 
(7) Facilities are maintained in proper operating condition, the toilet 
room is kept clean, equipped with self-closing doors, has no offensive 
odors, and if there is an adequate supply of toilet tissue available in the 
toilets. 
4.12 Handwashing Facilities.—An adequate number of lavatories with 
running hot and cold water shall be provided and preferably so located 
that their use by plant personnel can be readily checked. A supply of soap 
and individual towels shall be provided at all times and the facilities shall 
be maintained in proper operating condition. Signs shall be posted in 
the toilets and over the lavatory warning the employees to wash their hands 
thoroughly with hot water and soap and no employee shall return from 
a toilet to work in the plant without first having washed his or her hands. 
Public Health Reason: Washing facilities and sanitary towels are 
essential to the personal cleanliness of food handlers. 
Satisfactory Compliance: This item shall be deemed to have been satis- 
fied if: 
(1) There is at least 1 lavatory for every 20 employees. 
(2) The handwashing facilities are so located that the person responsible 
for supervision can readily observe that employees wash their hands 
before beginning work and after each interruption. 
(3) The lavatories are provided with both hot and cold running water. 
(4) There is a supply of liquid or powdered soap and proper dispensing 
facilities, together with individual towels available near the lavatory. 
(5) The facilities are maintained in proper operating condition. 
(6) Appropriate signs are posted in toilets and over lavatories. 
(7) These facilities (and only these facilities) are used by employees 
when on duty. 
4.13 Water Supply.—The plant shall be provided with an abundant 
supply of water, under pressure, from a source approved by the State 
health authorities. The supply shall be accessible to all parts of the plant, 22 
adequate in quantity, and of a safe sanitary quality meeting the Public 
Health Service Drinking Water Standards. No cross or backflow con- 
nections with unapproved water supplies or other possible sources of 
contamination shall be permitted. 
Public Health Reason: The water supply should be accessible so as to 
encourage its use in cleaning operations. It should be adequate so that 
cleaning, rinsing, and sterilizing of the equipment will be thorough; and 
it should be of safe, sanitary quality in order to avoid the contamination 
of the equipment and shellfish. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
(1) The water supply is easily accessible to all parts of the plant and 
is adequate for all purposes. 
(2) A hot water supply of adequate capacity is provided. 
(3) The water supply is approved by the State health authorities. 
(4) There is no connection between the safe water supply and water 
from an unsafe source through which it is possible to contaminate the safe 
water supply. 
(5) At least one inspection is made per year to determine whether the 
location, construction, and operation of the supply comply with State health 
department requirements. Bacteriological results on samples of water 
shall comply with the Public Health Service Drinking Water Standards. 
4.14 Personnel.—No person known to be affected with any disease in 
a communicable form, to be a carrier of such disease, or who has in- 
fected wounds or open lesions on the exposed portions of the body shall 
be employed in a shucking or packing plant. If the owner or manager 
has reason to suspect that any employee has contracted a communicable 
disease he shall immediately notify the proper health officials who will take 
such action as may be indicated. Pending such action by the health 
officials or the recovery of the employee, said employee shall be excluded 
from the plant. 
Public Health Reason: Persons who are infected with, or are carriers 
of organisms of typhoid fever, dysentery, septic sore throat, or certain other 
communicable diseases might transmit such disease to others through 
shucked shellfish. Persons with infected wounds or open lesions on the 
exposed portion of their bodies might likewise transmit the infecting 
organisms to the shucked shellfish and cause so-called food poisoning of 
the consumers. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
(1) Persons with infected wounds or open lesions on the exposed 
portion of their bodies and those who are known to be carriers of or are 23 
infected with typhoid fever, dysentery, or other communicable diseases 
likely to be transmitted by shucked shellfish are excluded from the plant. 
(2) Daily observations of employees are made by owner or manager 
with reasonable inquiries being made when signs of illness appear. 
(3) The inquiry indicates the possibility of a communicable disease, 
the ill employee is excluded from the plant pending clearance by the health 
officials or the complete recovery of the employee. 
(4) The inquiry leads to the suspicion of a communicable disease a 
prompt, complete report is made to the proper health officials. 
(5) Action is taken by the proper health officials upon receipt of such 
report. 
(6) Employees having diarrhea or sore throat promptly report this 
fact to the manager. 
4.15 Supervision.—The management shall designate an individual to 
be responsible for the compliance with those sections of this Manual 
having to do with plant cleanliness, personnel, and operation. 
Public Health Reason: The importance of handwashing by food 
handlers is great and unless someone is made responsible for this process, 
it is apt to be forgotten or overlooked. Satisfactory cleaning of the 
shucking room does not follow if the responsibility for the condition of 
the shucking room is divided among two or more persons. Clean floors, 
walls, and benches reduce the chances of contamination of the shellfish 
or shucking utensils during shucking operations. Daily cleaning of all 
surfaces will prevent mud from becoming dry and caked making it diffi- 
cut to remove. Periodic disinfection of the plant and the removal of 
accumulated contamination-, will reduce the possibility of contaminating 
the shellfish passing through the shucking room. 
Careful daily observation of the health of employees with proper 
inquiries when indicated and with exclusion of ill employees will tend 
to prevent possible contamination of the shucked stock with pathogenic 
organisms. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
A single individual has been designated by the management to supervise 
the activities above enumerated and if there is evidence that he has been 
carrying on his responsibilities satisfactorily. 
Shucking Room Equipment 
4.16 Shucking Benches and Stands.—The tops of shucking benches 
and the sides above the bench top to a height of at least 2 feet shall, 
when the benches are used to provide storage, be of smooth concrete, 
metal, or other nonabsorbent material, free from cracks or crevices and 24 
so constructed that drainage is complete and rapid. Shucking blocks 
shall be removable unless an integral part of the bench and shall be of 
solid one-piece construction. The stands or stalls shall be of finished 
material and painted where hand contact occurs. There shall be no boxes, 
shelves, or nails above the benches where miscellaneous articles might 
accumulate. 
Public Health Reason: Unless shucking benches, stands, blocks, and 
stalls are made of smooth material which can be cleaned easily, they will 
become very foul and materially affect the shellfish quality. Storing or 
hanging articles above shucking benches is undesirable, because of the 
chance that some article will fall into the shucked shellfish and because 
their presence interferes with thorough cleansing of the benches and 
adjacent walls. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
(1) The shucking benches are of smooth concrete, metal, or other 
nonabsorbent material free from cracks or crevices which might hold 
putrescible matter, and are maintained in a clean condition. 
(2) The benches drain completely and rapidly. 
(3) The shucking blocks are removable, or an integral part of the 
bench and are of solid, one-piece construction. 
(4) The stands or stalls are of finished material and painted where 
hand contact occurs. 
(5) There are no boxes, shelves, wires, or nails above the benches 
where shuckers’ gloves, finger cots, knives, or miscellaneous articles might 
accumulate. 
4.17 Rails.—All shucking pails or colanders shall be made of a not 
readily corrodible, smooth, impervious material and shall be constructed 
in such a manner as to eliminate grooves, seams, and cracks, where 
foreign particles, dirt, and slime might collect. All seams and joints 
shall be well filled with solder and dressed to a smooth surface. If “dip 
buckets” are used they shall be of the same quality as shucking pails. 
Public Health Reason: Shellfish containers and other utensils unless 
so constructed as to have flush joints and seams, smooth, easily cleaned, 
and accessible surfaces, and of durable noncorrodible metal are liable to 
harbor accumulations in which undesirable bacteria will grow. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if; 
(1) All containers, pails, colanders, and similar equipment are con- 
structed of smooth metal with a not readily corrodible surface, of a shape 
that will make cleaning easy, and with all joints and seams soldered 
smooth. 25 
(2) All containers, pails, colanders, and similar equipment are in 
good repair, free of breaks and corroded places. The use of agateware, 
rusted or dented pails is not acceptable. 
4.18 Knives and Blocks.—Knives shall be made of not readily cor- 
rodible, smooth, impervious material, and shall be constructed in such 
manner as to eliminate grooves, joints, and cracks where food particles 
and dirt might collect. The handles of opening knives and the breaking 
blocks shall be so constructed as not to have cracks and crevices which 
would retain food particles, dirt, and slime. 
Public Health Reason: Knives, breaking blocks, and breaking irons 
containing joints and cracks are not easily cleaned and are apt to harbor 
accumulation of slime and other material in which undesirable bacterial 
growth can occur. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
All opening knives, breaking blocks, and breaking irons are constructed 
and maintained in such manner that there are no open joints, seams, or 
cracks in which material may accumulate. 
4.19 Aprons and Finger Cots.—All persons who handle shucked shell- 
fish shall wear a clean apron or coat of washable or waterproof material 
which shall be kept reasonably clean. If finger cots are worn they shall 
be of clean washable or waterproof material. Similar shields for pro- 
tecting the palm of the hand shall be of clean washable or waterproof 
material, preferably rubber. 
Public Health Reason: Because the hands of all employees frequently 
come in contact with their clothing, it is important that the clothes worn 
during the handling of shucked shellfish be clean. The nature of their 
work makes it necessary that they wear some outer garment to cover 
the front of the clothing. This garment must be washable or waterproof. 
Finger cots unless kept clean become saturated with dirt which in turn 
contaminates the shucked shellfish. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
(1) Washable or waterproof aprons or coats are worn by all persons 
engaged in handling shucked shellfish. 
(2) Aprons and coats are kept reasonably clean and are stored in a 
place provided for the purpose. 
(3) Finger cots, if worn, are of clean, washable, or waterproof material. 
Operation 
4.20 Cleaning.—All utensils used in shucking, such as pails, knives, 
hammers, shucking blocks, and breaking irons, which ’come in contact 26 
with shucked shellfish, shall be thoroughly scoured until clean immediately 
following each day’s operations. Shucking pails shall be rinsed with 
running water before each filling. The practice of returning shucked 
shellfish to the shucker after delivery to the packing room should not 
be permitted. Floors, walls, and benches shall be washed free from 
accumulations of mud, shells, and shell chips with water within 2 hours 
after shucking operations for the day have ceased. 
Public Health Reason: Shucked shellfish cannot be kept clean if 
allowed to come in contact with unclean containers or utensils or if con- 
tainers or utensils are allowed to come in contact with dirty surfaces. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if; 
(1) All utensils and equipment such as pails, knives, hammers, shucking 
blocks, and breaking irons are thoroughly scoured until clean, using warm 
water and soap or an alkali cleanser. 
(2) Cleansing is performed within two hours after the day’s operation 
has ceased. 
(3) The plant supervisor is held responsible for the satisfactory cleaning 
of this equipment. 
(4) Shucking pails are rinsed with tap running water before each filling. 
(5) “Dip buckets,” if used, shall be rinsed and the water renewed each 
time the shucker delivers shucked shellfish to the packing room. 
(6) Floors, walls, and benches are washed free from accumulation of 
mud, shells, shell chips, and so forth with water from an approved source 
within 2 hours after shucking operations for the day have ceased. 
(7) After having been thoroughly cleaned, benches, blocks, and stalls 
are flushed at least once each week with hypochlorite solution containing 
50 p.p.m. or more of available chlorine or other disinfecting agent approved 
by the State regulatory authority. 
4.21 Bactericidal Treatment.—All utensils used in shucking, such as 
pails, knives, hammers, breaking irons, “dip buckets,” etc., which come in 
contact with shucked shellfish shall be subjected to bactericidal treatment 
after thorough cleansing within 3 hours of the termination of each day’s 
operations and be stored in a place where they are protected from con- 
tamination until used. Equipment so treated shall be protected from 
recontamination in storage. 
Public Health Reason: Regular periodic sterilization of all equipment 
will remove any chance contamination which may have reached the equip- 
ment since it was last sterilized. The importance of destroying any disease- 
producing organisms which may have reached the equipment is obvious, 
since such organisms may in turn contaminate the shellfish. The pos- 
sibility that the organisms may increase in number in the shucked shellfish 
increases the danger. 27 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if all the utensils and equipment such as pails, knives, hammers, 
and breaking irons have been; 
(1) Exposed in a steam cabinet for at least 15 minutes to a tempera- 
ture of at least 170° F., or for at least 5 minutes to a temperature of at 
least 200° F., said cabinet being equipped with an accurate indicating ther- 
mometer located in the coldest zone; or 
(2) Immersed in hot water at a temperature of 170° F. or more for 
at least 2 minutes; or 
(3) Exposed to hot air at a temperature of at least 180° F. for at 
least 20 minutes in a properly designed oven or hot-air cabinet equipped 
with an accurate indicating thermometer located in the coldest zone; or 
(4) Immersed in or exposed to a flow of chlorine solution prepared 
fresh each day for a period of at least 2 minutes. The initial strength 
of the solution shall be such that after final use it will contain not less than 
50 p.p.m. chlorine. 
AMOUNTS OF CHLORINE COMPOUNDS REQUIRED TO GIVE 
APPROXIMATELY 100 P.P.M. CHLORINE BY READILY 
AVAILABLE MEASURING DEVICES 
Volume of 
water—gallons 
Dry chlorine compounds 
available chlorine 
Liquid hypochlorite 
solutions 
available chlorine 
15 percent 
25 percent 
70 percent 
1 percent 
5 percent 
20 
5V2 tbs 
31/2 tbs 
IV2 tbs 
3 cups 
10 tbs. 
40 < • 
11 tbs 
6V2 tbs 
2% tbs 
3 pints 
114 cups 
60 
1 cup 
10 tbs 
3V2 tbs 
4% pints... 
2 cups 
80 
1% cups. . . 
13% tbs. ... 
tbs 
6% pints... 
74/2 cups 
100 
1% cups. . . 
1 cup 
6 tbs 
4 quarts ... 
3 cups 
150 
2% cups... 
1% cups.. . 
9 tbs 
6 quarts . .. 
4% cups 
200 
3% cups... 
2 cups 
12 tbs 
2 gallons... 
3 pints 
Note: 
Dry Measure 
1 tablespoon (tbs.)—approx. 0.3 oz. 
1 cup {y2 pint)—approx. 5 oz. 
Liquid Measure 
1 tbs. or 3 tsp.—approx. 15 ml. 
1 cup or y2 pint—approx. 16 tbs. 
4.22 Other Bactericides.—The inspector should not approve the use of 
any other form of bactericide until he has satisfied himself by his own 
or other official tests that it is satisfactory for use in connection with shell- 
fish sanitation, and that it is of adequate strength. The local inspector 
should consult his State board of health regarding all bactericides in use 
in his territory, so that he may be certain he is using the proper test. 28 
Under no circumstances shall formaldehyde or other preservative be used 
where such preservatives will come into contact with shellfish meats. 
4.23 Cabinets with Auxiliary Steam Boilers.—In medium and large 
shucking plants a steam cabinet with auxiliary steam boiler is the most 
satisfactory type of equipment for bactericidal treatment of utensils and 
equipment. (Detailed directions for the construction and operation of a 
steam cabinet may be obtained from the State regulatory authority. Di- 
rections for the construction of such a cabinet are given on pages 66 and 
67 of Public Health Bulletin No. 220 (1939 edition), Milk Ordinance 
and Code, obtainable from the Superintendent of Documents, Washington 
25, D. C). 
4.24 Hot Water Sterilization.—Use of hot water for bactericidal treat- 
ment shall not be accepted as satisfactory compliance unless the articles 
are completely immersed for at least 2 minutes in water maintained 
at 170° F. or higher throughout the period of total immersion. Pouring 
hot, or so-called boiling water, from vessel to vessel is not adequate and 
shall not be accepted. 
Sterilization with hot water can be accomplished in a vat. The vat 
should have sufficient depth to allow the complete immersion of at least 
one shucking bucket. 
An accurate indicating thermometer should be available in every plant 
so that the water temperature can be noted during the sterilization process. 
4.25 Storage of equipment.—All equipment used in the shucking 
process, including shucking pails, “dip buckets,” knives, breaking blocks, 
finger cots, etc., shall be left in steam cabinet or stored in other suitable 
place in the plant after cleansing and bactericidal treatment. 
Public Health Reason: Unless equipment that has been subjected to 
cleansing and bactericidal treatment is protected from contamination until 
it is used, it may easily become contaminated and in turn contaminate the 
shucked shellfish. Equipment taken home by shuckers may easily be ex- 
posed to material which might cause illness, especially in homes where 
cases of infectious diseases may be found. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
All equipment used in the shucking room is stored in a suitable box or 
locker protected from careless handling and from dust, splashing, dirt, and 
other contamination. 
4.26 Shell Disposal.—Shells from which meats have been removed 
shall be promptly removed from the shucking room and disposed of so 
that the shucked product can in no way become contaminated. 
Public Health Reason: When shells are allowed to accumulate in the 
shucking room, conditions are created which make it difficult to keep the 29 
room in a neat and clean condition. Under such conditions the shucked 
product is more apt to become contaminated than if the shucking room is 
kept clean, neat, and orderly. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if the shells are removed from the shucking room with sufficient 
promptness to prevent interference with the sanitary operation of the plant. 
Among the methods approved for the removal of shells are the following: 
(1) Disposition through a hole in the shucking bench leading to the 
area beneath the bench which is closed off from the shucking room and 
open to the outside of the house. 
(2) Depositing the shells on moving conveyor belts which continu- 
ously remove the shells from the shucking room. 
(3) Depositing the shells in baskets, barrels, or wheelbarrows provided 
beside each shucker, such baskets, barrels, or wheelbarrows to be promptly 
removed when full. 
4.27 Miscellaneous.—Miscellaneous equipment not necessary to carry 
out the shucking processes shall be excluded from the shucking room. All 
unused or abandoned equipment or material foreign to this particular 
business shall be removed from the operating part of the plant. All domes- 
tic animals and rodents shall be excluded from all parts of the plant. The 
shucking and packing portions of the plant, when in operation, shall be re- 
stricted, to the handling of shellfish to prevent accumulation of material 
and articles which would hinder cleaning or might contribute to the con- 
tamination of the shellfish. 
Public Health Reason: The presence of miscellaneous and extraneous 
equipment and material in the shucking room interferes with the proper 
cleansing of the room and equipment, and its presence may result in con- 
taminating the food product handled in the shucking room. The habits 
and characteristics of the dog, cat, rat, or other domestic animals, or 
rodents are such that their presence near shell stock or shucked stock 
increases the possibility of it becoming contaminated. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
(1) All equipment and material not actually employed in the shucking 
process are excluded from the shucking room. 
(2) The shucking and packing portions of the plant are not used simul- 
taneously for the handling of shellfish and the carrying on of other 
operations. 
(3) There is no accumulation of miscellaneous articles in the plant not 
stored in their proper place. 
(4) There is no evidence of the presence of domestic animals and 
rodents. 30 
(5) No shellfish containers or equipment are stored, handled, or used 
beneath overhead sewer, water, or drain lines unless such pipes are pro- 
vided with suitable means of carrying off possible leakage or condensation. 
Packing and Shipping Room Equipment: 
4.28 Utensils (skimmers, blowers, and so forth).—All packing equip- 
ment such as skimmers, tanks, tubs, measures, colanders, paddles, and so 
forth shall be made of not readily corrodible, smooth, impervious material 
and constructed in such a manner as to eliminate grooves, seams, and 
cracks where foreign material and slime might collect. All seams and 
joints shall be well filled with solder and dressed to a smooth finish. A 
stand or shelf shall be provided under all chutes from skimmers or blowers, 
to support a measure or can. The surfaces of skimmers, blowers, tubs, 
tanks, and other utensils with which shucked shellfish come in contact 
shall be free of paint and rust. The air pipes in the blower shall be re- 
movable or so located that cleaning is not difficult. The portion of the air 
pipes below the tank liquid level shall be of smooth, not readily cor- 
rodible, impervious material. There shall be a sterilization connection of 
adequate size to the air line of the blower above the tank liquid level by 
which steam or hot water may be forced through the line. 
Perforations in the skimmers, colanders, and blower trays shall be 
smooth to facilitate cleaning. Skimmers, ladles, and colanders of wire 
mesh construction are not permitted. Several types of blowers have nar- 
row and deep compartments along their sides or at corners, separated from 
the main part of the blower by a perforated plate. The area thus formed 
is very difficult, if not impossible, to clean and offers an ideal place for dirt 
and slime to collect. Where this occurs the plates should be removed or 
the space tightly sealed from the main part of the tank. 
Pipes should be supported at a sufficient distance above the bottom of 
the tank to allow easy passage of a brush between the pipes and tank 
bottom. 
Air pump intakes should be protected against contamination. 
Shallow tanks and tubs should be elevated by legs, by a table, or by a 
bench to raise the top rim at least 3 feet above the floor. 
Tables and shelves shall be made of materials that can be cleaned 
readily. 
The washing of shellfish by “blowing” is not always necessary and in 
many instances produces an inferior product. Where “blowing” is prac- 
ticed, attention is directed to the requirements of the United States Food 
and Drug Administration promulgated to prevent adulteration of shucked 
stock. 
Public Health Reason: Containers and utensils which have joints and 
seams, inaccessible surfaces, and are constructed of nondurable or non- 31 
corrodible metal, are apt to harbor accumulations in which undesirable 
bacterial growth is produced. Paint on surfaces may peel on being ex- 
posed to continuous wear and the peeled paint may enter the packing can 
with the shellfish. The slime and foreign material which accumulates in air 
pipes and blowers .below the tank liquid level affords an excellent breeding 
place for bacteria at each blowing. Such material may be dislodged and 
forced into the batch of shucked shellfish then in the blower, thus seeding 
the shellfish with organisms which may cause their spoilage or produce 
illness in consumers. 
Tables and shelves unless made of materials that can be cleaned readily 
will not be cleaned properly and may harbor accumulations in which 
undesirable bacterial growth is produced. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
(1) All multiuse containers, utensils, and other equipment are con- 
structed of smooth metal with a not readily corrodible surface, of a shape 
that will make cleaning easy, and with all joints and seams soldered 
smooth. 
(2) All multiuse containers, utensils, and other equipment are in good 
repair, free of breaks, and corroded places. 
(3) A stand or shelf located about 2 feet above the floor is provided 
under all chutes from skimmers and blowers. 
(4) The surfaces of equipment coming in contact with shucked shell- 
fish are free of paint and rust. 
(5) Air pipes in blowers can be removed readily. 
(6) The entire blower line below the liquid level can be easily cleaned. 
(7) There is a connection to, or a removable section in, the blower 
line, above the liquid level of the tank, where steam or hot water can be 
introduced. 
(8) Tables and shelves are made of materials which can be cleaned 
readily. 
(9) Air pump intakes are so located as to be protected against 
contamination. 
4.29 Shipping Containers.—Shucked shellfish shall be packed and 
shipped either in single-service containers made of clean, impervious mate- 
rials positively sealed or in such containers so sealed that tampering with 
the container can be detected. 
The packer’s certificate number preceded by the State abbreviation shall 
be impressed, embossed, lithographed, or otherwise permanently recorded 
on the container or on the cover if the cover becomes an integral part of 
the container during the sealing process. 
Public Health Reason: Unless shucked shellfish are packed in clean 
containers and sealed so that they cannot be tampered with while en route 32 
to the final point of destination, all precautions taken to produce a clean 
and safe product prior to packing may be wasted. The opening of con- 
tainers of shucked shellfish by intermediate handlers may subject this 
food product to needless and possible filthy handling, destroying the 
benefit of careful and judicious processing. The approximate number 
of shucked shellfish in any container can be stated on a label or elsewhere 
so that inspection for this purpose will not be necessary. Labeling the 
container is necessary to facilitate tracing the product to its source. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
(1) Shipping containers are of metal, waxed paper, glass, or other 
material of such design that after sealing, opening the container, or tamper- 
ing with the seal will be evident. 
(2) All shipping containers are clean when packed. 
(3) All shipping containers are stored in a clean place. 
(4) Packer’s certificate number is impressed, embossed, or otherwise 
permanently recorded on the container or an integral part thereof. 
(5) Returnable containers are made of noncorrodible, smooth, dur- 
able material; with straight walls and tight-fitting covers; and with all 
seams and joints flush and dressed to a smooth surface. 
4.30 Refrigeration Facilities.—Refrigeration facilities shall be provided 
capable of cooling shucked shellfish to a temperature of 50° F. or less 
within 2 hours after the shellfish are shucked and keeping them at or 
below 50° until delivered to the consumer. If shucked shellfish are frozen 
they shall be kept in a frozen condition until delivered to the consumer. 
Where a refrigerator or ice box is used, it shall have adequate capacity 
to store all shucked stock received by or packed in the plant during the 
day. The refrigerator or ice box should be well insulated and have an 
impervious lining; the floor should be graded to drain quickly; and 
an accurate thermometer shall be kept in the refrigerator at a point 
predetermined to have approximately the highest temperature. 
Public Health Reason; Shucked shellfish are an excellent medium for 
the growth of bacteria at temperatures above 50° F., and it is essential 
that the temperature of shucked shellfish be kept below 50° F. in order to 
keep bacterial multiplication to a minimum. The likelihood of contracting 
disease is much increased when shellfish contain excessive numbers of 
harmful bacteria and for this reason it is extremely important that they 
be quickly cooled so that any small numbers of bacteria which may have 
entered shall not be permitted to multiply. High temperature may also 
be responsible for physical deterioration and spoilage of shucked stock. 
Alternate freezing and thawing of shellfish hastens deterioration and 
spoilage which may cause illness in the consumer. 33 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
(1) Shucked shellfish can ,be cooled to a temperature of 50° F. or 
less within 2 hours after being shucked, but are not frozen, and crushed 
ice in a clean, well-drained bin, chest, or ice box or a refrigerator free 
from excessive odors is provided for storage; or if 
(2) The shucked shellfish are packed in packages in which they will 
reach the consumer unopened, and facilities are provided whereby shucked 
shellfish may be quickly frozen and stored at below freezing temperatures 
until delivered to the consumer. 
4.31 Ice.—lce used in cooling water for processing of shucked stock 
or for cooling shucked stock during processing shall be obtained from an 
approved source and shall be stored and handled in a cleanly manner. 
No ice shall be allowed to come in contact with shucked stock after process- 
ing has been completed. 
Public Health Reason: There is the possibility of ice becoming con- 
taminated during the manufacturing process and in the storing and 
handling subsequent to manufacture. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
(1) Ice is manufactured from water meeting the bacteriological re- 
quirements of the Public Health Service Drinking Water Standards or is 
approved by the State regulatory authority. 
(2) Ice is stored in such manner that it will not come in contact with 
floor or other drainage. 
(3) Ice is thoroughly washed before .being placed in blowers, tanks, 
tubs, buckets, or cans, in which shucked shellfish are subsequently placed. 
(4) All materials employed in handling and preparing the ice for use 
are used for no other purpose and are kept clean. 
4.32 Bactericidal Treatment Facilities.—Facilities for bactericidal treat- 
ment of packing equipment such as skimmers, tanks, tubs, measures, 
colanders, and paddles, which come in contact with shucked shellfish, 
shall be provided. 
Public Health Reason: Mere cleaning of utensils and equipment does 
not insure that all disease-causing organisms which may have been present 
will have been removed or destroyed. Even very small numbers thus 
remaining may grow to dangerous proportions if transferred to shucked 
shellfish. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
Facilities are provided for adequate bactericidal treatment of skimmers, 
tanks, tubs, measures, colanders, and paddles. Such treatment will be 34 
considered to be adequate if the articles above enumerated have been 
exposed to one or more of the bactericidal treatments described in 4.21, 
p. 26. 
4.33 Clothing and Aprons.—Persons working in the packing room 
shall wear clean outer garments protected with clean waterproof or wash- 
able aprons or coats. When manual handling of shucked shellfish which 
have received their final washing becomes necessary, clean rubber gloves 
shall be worn, or the hands shall be washed immediately before such man- 
ual handling. 
Public Health Reason: Because the hands of all employees frequently 
come in contact with their clothing it is important that the clothes worn 
during the handling of shucked shellfish be clean. The nature of the 
employees’ work makes it necessary that they wear some outer garment to 
cover the front of the clothing. This garment must be washable or 
waterproof. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
(1) Washable or waterproof aprons or coats are worn by all persons 
engaged in handling shucked shellfish. 
(2) Aprons are kept scrupulously clean. 
(3) All aprons and clothes not in use are stored in a cloakroom or locker 
room provided for this purpose. 
(4) Rubber gloves, if used, are bactericidally treated and then stored 
with the utensils so treated. 
Operation: 
4.34 Cleaning (Utensils and Building).—The floors, walls, and if neces- 
sary the ceiling of the packing room shall be cleaned at the end of each 
day’s operations and flushed with water meeting the Public Health Service 
Drinking Water Standards. Windows and skylights should be kept clean. 
Refrigerators or ice boxes shall be washed out once a week or more often 
if necessary. All packing equipment, such as skimmers, tanks, tubs, 
measures, colanders, and paddles, which come in contact with shucked 
shellfish, shall be thoroughly scoured until clean at the end of each day’s 
operations. Air pipes in blowers shall be removed daily at the end of 
packing operations and their interior and exterior surfaces be thoroughly 
cleaned. 
Public Health Reason: Clean floors, walls, and ceiling reduce the 
chances of contamination of shucked shellfish during the time they are 
being washed and packed. Periodic cleaning of the refrigerators or ice 
boxes is necessary to remove dirt or foreign material from the walls and 
floor which might be carried into the room by foot traffic and by ice, and 
to reduce odors which might result in a confined space. Shucked shell- 35 
fish cannot be kept clean if allowed to come in contact with unclean con- 
tainers or utensils. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if; 
(1) The floors, walls, and ceiling of the packing room are free from 
accumulations of dirt and other wastes except those which have accumu- 
lated since the beginning of the day’s operation, provided such accumu- 
lation is removed within 2 hours after packing operations have ceased. 
(2) All dirty surfaces have been flushed with water meeting the Public 
Health Service Drinking Water Standards, after accumulations have been 
removed. 
(3) Windows and skylights are clean. 
(4) The refrigerator or ice box is clean and free from excessive odors. 
(5) All utensils and equipment such as skimmers, tanks, tubs, mea- 
sures, colanders, and paddles are thoroughly scoured until clean, using 
warm water and soap or an alkali cleanser. 
(6) Cleaning is performed within 2 hours after the day’s operations 
have ceased. 
(7) Air pipes in blowers are removed daily at the end of packing 
operations and their interior and exterior surfaces are thoroughly cleaned. 
4.35 Bactericidal Treatment.—All packing room equipment such as 
skimmers, tanks, tubs, measures, colanders, and paddles, which come in 
contact with shucked shellfish, shall ,be sterilized after cleansing. 
Cleansing and sterilization operations shall be carried on within 3 
hours of the terminating of each day’s operations and equipment be stored 
until used in a place where it will be protected from contamination. Large 
equipment which cannot be stored in a protected place shall be cleaned at 
the end of each day’s operations and be subjected to bactericidal treatment 
immediately before use. 
Public Health Reason: Since mere cleaning of utensils and equipment 
with which shucked shellfish come in contact does not insure that all 
disease organisms which may be present will be removed or destroyed, it 
becomes necessary to apply bactericidal treatment to such equipment. 
Even very small numbers of organisms may be sufficient to seed packed 
shellfish and grow to dangerous proportions before such shellfish are 
consumed. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
The articles above enumerated have been subjected to one or more of 
the bactericidal treatments described in Sec. 4.21, p. 26, in accordance 
with the satisfactory compliance requirements stated therein. 
4.36 Equipment Storage.—All equipment with which shucked shellfish 36 
in the packing room come in contact shall, after thorough bactericidal 
treatment, be stored in such manner as will protect it from contamination 
before it is again put to use. 
Public Health Reason: All of the precautions taken in sterilizing equip- 
ment may be undone by improper storing of the equipment following 
treatment. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
(1) The equipment is stored in a cabinet where it will be protected 
from dust, drippings, splashings, flies, rodents, domestic animals, or 
unauthorized handling. The utensils may remain in the steam chest in 
which sterilization has taken place or in the hot water vat or tank in which 
bactericidal treatment has been applied if they are fully protected from 
contamination prior to use, or may be 
(2) Stored in the packing room on clean shelves, stands, tables, or 
wires if the packing room is locked so as to exclude all unauthorized 
persons. 
4.37 Packing Shucked Stock.—Shucked shellfish shall be packed in con- 
tainers dated and sealed (Sec. 4.29, p. 31). If the shucked shellfish have 
not been subjected to a quick-freeze process they shall be cooled to a tem- 
perature between 32° F. and 50° F. within 2 hours after shucking and be 
kept at that temperature. After tub washing or blowing, the washed 
shellfish shall not be exposed to contamination. 
Public Health Reason: Unless shucked shellfish are packed in con- 
tainers which are sealed after packing, they may be opened by unau- 
thorized persons and become contaminated. Proper identification and 
dating of the container is necessary to facilitate tracing the product to 
its source. Unless shucked shellfish are kept at low temperatures until 
they are consumed undesirable bacterial growths may result in their 
spoilage and thus cause illness. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if; 
(1) Date of shucking is impressed, embossed, or otherwise permanently 
recorded on the container or an integral part thereof. 
(2) Shucked shellfish, not subjected to quick-freezing process, are 
cooled to a temperature between 32° F. and 50° F. within 2 hours after 
shucking, and sealed in containers and are stored and shipped in such 
manner as will hold their temperature between 32° F. and 50° F. If 
subjected to quick-freezing process the temperature of the shucked shellfish 
shall be held at 10° F. or lower. 
(3) Washed shellfish are not exposed to contamination before being 
packed. 37 
4.38 Repacking Shucked Stock.—The packing of shucked shellfish 
preferably should take place only in the same plant as the one in which 
they are shucked. If repacking is practiced, it shall be done strictly in 
accordance with all the requirements stipulated for packing plants. The 
stock to be repacked must be received at the repacking plant in approved 
shipping containers. Containers shall be coded to show the earliest date 
of shucking of stock packed therein, as well as the plant or plants in which 
the stock was shucked. This information shall be made a part of the plant 
record. 
Public Health Reason: The repacking of shucked shellfish in plants 
other than those in which they have been shucked exposes the shucked 
shellfish to additional and unnecessary handling, subjects them to further 
possibilities of contamination, and brings about greater deterioration due to 
lengthening the time interval between the shucker and the consumer. 
Combining in one pack shucked shellfish from more than one source per- 
mits the possibility of contamination of the entire pack should the shellfish 
from any one of the sources be contaminated. Where repacking is prac- 
ticed tracing of shellfish to its source is difficult. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
(1) Repacking is practiced strictly in accordance with all the re- 
quirements stipulated for packing plants. 
(2) The stock to be repacked is received at the repacking plant in 
approved shipping containers at proper temperatures. 
(3) Containers are marked with the name of the shucking plant, its 
certificate number, and coded to show the earliest date of shucking of 
the stock packed therein. 
4.39 Packing and Shipping Shell Stock.—The washing of shell stock, 
when necessary, should be done either with water obtained from sources 
approved by the State regulatory authority or from approved shellfish 
areas. All shell stock, except that consigned to a shucking plant, shall 
be packed and shipped in clean containers such as barrels, bags, crates, 
or boxes under conditions which will prevent spoilage or contamination. 
When consigned to shucking plants in bulk, shell stock may be packed and 
shipped in such vehicles as clean railroad cars, trucks, and boats, under 
conditions which will prevent spoilage or contamination. Storage facili- 
ties should be at least equal to those described in Sec. 4.4, p. 17. A dealer 
holding a certificate for shell stock only, or as a reshipper, shall not shuck 
any shellfish. 
Public Health Reason: If shell stock are washed in polluted water, the 
shellfish may become contaminated. If spoilage or contamination is not 
prevented, illness and possible death may result from the consumption of 38 
such shellfish. The establishment of a dealer holding a certificate for 
shell stock only or as a reshipper is not required to meet the provisions 
set forth in this manual for shucking plants; if shellfish are shucked in 
this type of establishment, the shucked stock is more likely to become con- 
taminated and cause disease because adequate facilities and equipment 
are not available to permit shucking in a clean manner. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
(1) Water for washing shell stock is obtained from shore sources ap- 
proved by the State regulatory authority or from approved shellfish areas. 
(2) Shipping containers such as boxes, barrels, crates, and bags, and 
vehicles used in transportation such as railroad cars, trucks, and boats 
are clean. 
(3) Trucks and other conveyances are covered and the shellfish therein 
maintained at temperatures which will keep them alive yet prevent them 
from freezing. 
(4) Shellfish are not shucked by a dealer holding a certificate for 
shell stock only or as a reshipper of shell or shucked stock. 
(5) Dry storage facilities are at least equal to those described in Sec. 
4.4, p. 17. 
4.40 Identification of Shell Stock on the Market.—Shell stock shall 
be identified by a tag or label securely fastened to the shipping container 
and bearing the certificate number of the shipper, his name and address, 
the name and address of the consignee, and the kind and quantity of shell 
stock in the container. 
Public Health Reason: The prompt discovery and elimination of 
contaminated shellfish is necessary to protect the health of shellfish 
consumers. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
(1) Tags are securely fastened to all containers in which shell stock 
is shipped. 
(2) Tags are made of substantial stock, reasonably waterproof, and at 
least 2y&' x in size. 
(3) The information on tags includes the name, address, and certificate 
number of the shipper, the name and address of the consignee, and the 
kind and quantity of shell stock in the container and, either coded or 
uncoded, the date the shellfish were taken from the water. 
4.41 Records.—To permit tracing readily to the point of origin any 
shellfish on the market, it is necessary that complete and accurate records 
be kept by every shellfish dealer. 
Public Health Reason: In case of an epidemic of disease attributable 
to shellfish, it is necessary that health departments be able to determine 39 
the source of contamination and thereby prevent any further epidemic 
from this source. This can be done most effectively by following the course 
of a shipment of shellfish through all the various dealers who handle it, 
back to the point of origin by records kept by every shellfish dealer. 
Satisfactory Compliance: This item shall be deemed to have been 
satisfied if: 
(1) Shell stock dealers’ records include the date, persons from whom 
purchased, quantity and kind of shellfish, and the dealers to whom sold. 
(2) Reshippers record the dates and names of dealers from whom pur- 
chases are made arid those to whom sales are made, together with kind and 
quantity of shellfish involved. 
(3) Shuckers record the dates and dealers from whom purchases are 
made or areas from which shellfish are taken and names of persons to whom 
sold. 
(In most cases, the record of the financial transactions of the plant 
constitutes a sufficient record as defined in this section.) INDEX 
Administrative Procedure in the Sanitary Control of the Shellfish Industry.. 1 
Procedures to be followed by the State 1 
Procedures to be followed by the Industry 2 
Procedures to be followed by the Public Health Service 2 
Air, Hot, use of as a bactericidal treatment 27 
Animals, domestic and rodents, to be excluded from all parts of the plant.. 16,29 
Aprons, in shucking plants 25 
in packing plants 34 
Areas, Shellfish Growing—See Shellfish Growing Areas 4 
Page 
Bactericidal Treatment 
Kinds of 27 
shucking utensils and equipment 26 
packing utensils and equipment 33 
Bactericides, commercial and proprietary . 27 
Bacteriological examinations for shellfish and shellfish growing waters— 
See Surveys, Bacteriological H 
Bacteriological Standards—See Most Probable Number of coliform organisms 12 
“Blowing” of shellfish 30 
Boats used for tonging, dredging or transporting shellfish (“buy boats”) 
requirements of 10 
Body Wastes in boats, disposal of 10 
Bacteriological Surveys—See Surveys, Bacteriological 11 
Boots worn only in conditioning plants, to be washed in chlorine solution .... 14 
Breaking Blocks and irons, knives 25 
“Buckets, dip” 26 
Cabinets with auxiliary steam boilers, considered appropriate for medium- 
sized and large shucking houses 28 
Carriers, communicable diseases, etc. excluded from the plant 22 
to be reported to the Health Officer 22 
Certificate number, packer’s to be impressed or embossed on shellfish container 2, 31, 37 
Chlorine Solutions 
Use of, in shucking plants , 27 
approved strengths 27 
for washing boots before entering conditioning plant 14 
use of, in shucking benches, blocks, and stalls 26 
Classification of Shellfish Areas 5 
Cleaning shellfish by blowing 30 
Cleaning 
utensils and equipment, floors, walls, and ceiling of shucking room 25 
utensils and equipment, floors, walls, and ceiling of packing room 34 
responsibility of plant supervisor 23 
Cleansing 14 
tanks IS 
personnel, requirements of 16 
minimum period of treatment 15 
oxygen content of cleansing water IS 
quality of cleansing water 15 
40 41 
Conditioning 13 
Conditioning plant—See Conditioning Tanks also 13 
Requirements of personnel 14 
washing of boots in chlorine solution before entering 14 
Conditioning tanks, 
requirements of 13 
drainage of floor or ground surfaces adjacent to 14 
oxygen content of cleansing water 14 
quality of water for 14 
Clothing stored on walls, shucking benches and tables, prohibited 18 
Containers, Shipping 
single-use for shucked shellfish 31 
for shell stock 37 
for repacking 37 
Cots, finger 26 
Cultivation of shellfish near shore—See also Floating and Wet Storage 16 
Page 
Delivery window between shucking and packing rooms 17 
Depletion of Closed Shellfish Areas 10 
to be carried out at 2-year intervals 10 
removal operation 10 
Disposal of shells 28 
Doors, self-closing and outward opening, for packing rooms 19 
Dry Storage 17 
Excretions, Body 
disposal of, in boats used for transporting shellfish 10 
metal containers for 10 
Equipment and utensils 
air pipes in blower 30 
air pump intakes 30 
bactericidal treatment of in shucking plant 26 
bactericidal treatment of in packing room 35 
cleaning of, in packing room 34 
cleaning of, in shucking plant 25 
general construction details in packing room 17, 18 
quality of water for cleaning 21 
shallow tanks and tubs to be elevated above floor 30 
stands or shelves to be provided under chutes from skimmers and 
blowers 30 
sterilization connection to air line of blower required 30 
storage of, in shucking plant 28 
use, storage of, prohibited beneath overhead sewers, water of drain lines 30 
Finger Cots 25 
Floating—See Conditioning Tanks, Cleansing 13 
Floating and Wet Storage 16 
Sketch of locale to be included with State written approval 17 
Floats, use of, in sanitary surveys 4 
Formaldehyde and other preservatives use of, prohibited in shellfish meats 28 
Garments stored on walls, shucking benches and tables, prohibited 18, 24 
Handwashing, 
supervision by a single individual in shucking plant 23 42 
Harvesting and Gathering 10 
requirements of boats 10 
Hibernation 7 
Hot water as a bactericidal treatment—See water, hot 28 
Page 
Ice • 33 
Ice Box, cleaning of 35 
Icing of shucked shellfish 32, 36 
Identification and tracing of suspected shellfish shipments 38 
Irons and blocks 25 
Knives, opening 25 
Lavatories required .. 20 
List of certified interstate shippers of shellfish published by the Public Health 
Service 2 
Most Probable Number (M.P.N.) of coliform organisms per 100 ml. of 
sample 12 
allowable for Moderately Polluted Restricted shellfish areas 7 
allowable for Approved shellfish areas 6 
allowable for oyster shell stock and shucked oysters 12 
allowable for shellfish other than oysters 12 
allowable for shellfish to be cleansed 8 
Mussels and Clams, Examination for the presence of poison 12 
Packing and Shipping Room 
bactericidal treatment facilities 33 
clothing and aprons in 34 
ice 33 
packing shucked stock 36 
packing and shipping shell stock 37 
refrigeration facilities 32 
shipping containers, sealing and storing 31 
storing of equipment 35 
Personnel, 
shucking and packing plant 22 
with wounds on exposed part of body or suspicious illness to be excluded 
from plant 22 
Pollution, sewage 4 
in Grossly Polluted closed areas 6 
in Moderately Polluted restricted areas 7 
Policing of Closed Areas 9 
warning signs to be posted 9 
patrol by State regulatory authority 9 
descriptions of closed areas 9 
maintenance of record data 9 
Procedures, Administrative—See Administrative Procedures 1 
Quality of water—See Water, Quality of ... 21 
Rating and inspection of shucking and packing plants by the Public Health 
Service 2 
Records of interstate shipments of shellfish, required 38 
Rats, domestic animals, to be excluded from plant 17, 29 
Records, plant, to be kept by every shellfish dealer 38 43 
Refrigeration, 
of shucked shellfish 32, 36 
facilities in packing room 32 
cleaning of refrigerator or ice box 35 
Re-laying of shellfish 8 
in Approved areas , 8 
from a polluted area to an Approved area 8, 9 
Repacking of shucked shellfish 37 
Page 
Sampling stations for bacteriological examination 6 
Spacing 6 
Location on chart 6 
Separation of shucking from washing and packing processes 17 
Shellfish 3 
market 3 
seed 3 
identification of 38 
shucked 4 
stock 4 
Shellfish Growing Areas 4 
Approved areas 5 
Grossly Polluted, closed areas 6 
Moderately Polluted, restricted areas 7 
Illustrative sketch T 4 
Shells, disposal of 28 
Shipping and packing room—See packing and shipping room 30 
Shipping containers for shucked shellfish to be single-use 31 
Shell stock 
packing and shipping 37 
identification 38 
Shucking Plant 
Arrangement 17 
Floors ' 18 
Handwashing facilities 21 
Heating and ventilation 20 
Light requirements 19 
Personnel requirements 22 
Screening 19 
Supervision 23 
Toilet facilities 20 
Walls and ceiling 18 
Water supply 21 
Shucking room 23 
aprons and finger cots 25 
benches, blocks, and stands 23 
cleaning of equipment and utensils 25, 26 
equipment 23 
finger cots 25 
knives and blocks 25 
operation 25,26 
pails 24 44 
stands 23 
utensils 24,25 
Signs, warning—See Warning Signs 9 
Sign, washing, hand 21 
Sketch illustration kinds of shellfish growing areas 4 
Steam, exposure to, as a bactericidal treatment 27 
Sterilization of utensils and equipment—See Bactericidal Treatment, Clean- 
ing, and Chlorine Solutions 27,28,33 
Storage, 
£>ry , 17 
Wet and floating 16 
Surveys, 
bacteriological 11,12 
sanitary 5, 6 
frequency of, in approved shellfish areas , 6 
Page 
Tanks, Conditioning—See Conditioning Tanks 13,14 
Temperature, refrigerating, for shucked shellfish 36 
Temperature requirement, quick-freezing process 36 
Thermometer required in hot water sterilization 28 
Thermometer required for refrigerator or ice box 32 
Tide, conditions of, 
in sanitary surveys 5 
in bacteriological surveys ' 6 
Toilets, 
in shucking plants 20 
Utensils and equipment—See equipment and utensils 
Warning Signs, 
in closed areas 11- 
in toilets and lavatories in shucking plants 21 
Wastes, Body, disposal in boats 10,11 
Water, Hot, use of, as a bactericidal treatment 28 
operating details 21,22 
Water, Quality required 
in conditioning tanks 14, 15 
in cleansing tanks 15 
in boat cleansing 10 
in cleaning utensils and packing plant 34 
in packing room 34 
in shucking plants 26 
in washing shell stock 37 
oxygen content in cleansing tanks 15 
Window, Delivery, between shucking and packing rooms 17