PA? U. S. BUREAU OF FISHERIES 
PRESERVATION OF FISHERY PRODUCTS FOR FOOD 
Studies on this phase of fishery technology are conducted in the 
field of chemistry, bacteriology, and engineering. These studies are 
for the purpose of improving the quality of fishery food products; 
development of scientific tests for judging the quality of fishery 
products; development of methods for improving the ‘sanitary con- 
ditions in fish-packing plants; and the development of additional 
fresh, frozen, cured, and canned fish foods. During the past year 
there have been many demands on the Bureau for research on prob- 
lems of this type. This is indicative of the desire of the fishery 
industry to place on the market a food product which will meet 
the most exacting requirements as to quality and wholesomeness, and 
of the desire to make the most effective use of the fishery harvest. 
Not only has the fishery industry been instrumental in having these 
studies conducted, but it has been quick to adapt to commercial 
practice many of the recommendations of the Bureau resulting from 
this work. During 1939 studies on the preservation of fishery 
products for food were conducted in the Bureau’s technological 
laboratories at College Park, Md., Seattle, Wash., and Washington, 
D.C. 
PREPARATION OF CRAB MEAT 
Bacteriological and chemical studies of the commercial preparation 
of the meat of the blue crab (Callinectes sapidus), which were begun in 
1938, were continued during the past year. These studies were 
conducted for the purpose of developing more rapid chemical and 
bacteriological tests for judging the quality of crab meat, for exploring 
new methods for the packing of crab meat, for effecting improvements 
in plant equipment, and for more efficient and sanitary handling of 
crab meat. Following the completion of the work at a temporary 
laboratory in Crisfield, Md., where bacteriological investigations of the 
various operations required in the preparation of crab meat were made 
under actual plant conditions, the laboratory equipment was returned 
to the Bureau’s laboratory at College Park, Md., where additional 
work was conducted. 
Studies to develop a more rapid chemical test for determining the 
quality of crab meat were conducted on the product as stored in ice 
under the same conditions as practiced commercially. The following 
chemical reactions were given consideration as a basis for possible 
tests for detecting freshness in the crab meat: Degree of acidity or 
alkalinity (pH), ammonia formation, hydrogen sulfide formation, and 
the electrometric test for relative freshness.* In studying the degree 
of acidity or alkalinity of the crab meat, it was found that the pH of the 
“lump” or white meat increased from about 7.2 in the fresh product 
to about 7.9 in the stale meat, while the claw meat showed very little 
variation in pH between the fresh and the stale product. This 
indicates that the pH test has promise of commercial application at 
least on the white meat. In studying the formation of ammonia in 
the crab meat under storage, it was found to increase steadily to a 
value of about 400 parts per million for white meat and 500 parts 
per million for claw meat, when a stale odor was evident. This reac- 
4 The electrometric test was developed for testing the quality of fish such as haddock by technologists of 
the Bureau of Fisheries. The details of this test are contained in ‘“‘An Electrometric Method for Detection 
of Relative Freshness of Haddock,’’ by Maurice E. Stansby and James M. Lemon,U.S. Bureau of Fisheries. 
Industrial and Engineering Chemistry, Vol. 5, pp. 208-211, May 1933. 
r 
