2-11. MICROBIOLOGY OF SHELLFISH AND CRUSTACEANS
Shellfish and crustaceans (also waterfoods) are subject to many types of
microbial spoilage. Extensive bacterial spoilage can be detected without any difficulty
by organoleptic testing. However, it is impossible to detect the presence of pathogenic
organisms organoleptically. Yeast spoilage is not uncommon in oysters that have been
handled improperly, and this results in "pink oysters," which are considered to be
inedible. Oysters may harbor pathogenic organisms when they are grown in water
contaminated by such agents as sewage wastes. It is for this reason that water in
which oysters are grown is tested for coliform organisms. The number of coliform
organisms serves as an index relative to the contamination of the water. White shrimp
are subject to a type of microbial spoilage that results in the development of an inedible
"red shrimp." This condition should not be confused with the pink species of shrimp,
because a pink color is entirely normal.
Section V. MICROBIOLOGY OF FRUITS AND VEGETABLES
2-12. INTRODUCTION TO FRUITS AND VEGETABLES
a. Overview. Fruits and vegetables are considered by many individuals to be of
little importance in serving as vehicles for the transmission of pathogenic organisms.
Such an assumption, if based entirely on the situation existing in the United States (US),
would be partially valid. Even in this country, in spite of our high sanitary standards,
fruits and vegetables still are a factor to reckon with in the transmission of intestinal
diseases. In many parts of the world, fruits and particularly vegetables are of major
importance in disease transmission. This is especially true in those countries
maintaining poor sanitary standards. Hunger and epidemics traceable to contaminated
plant foods always exist together.
b. Unsanitary Growing Conditions. Human fecal material is commonly used
as fertilizer in the Orient. Vegetables grow in intimate contact with the soil and are
readily contaminated by the organisms of cholera, dysentery, and typhoid fever. The
prevalence of these diseases and other intestinal diseases is directly related to the
degree with which vegetables are fertilized with human fecal material. Fruits and
vegetables are normally processed and distributed under conditions much more
unsanitary than is the case with animal origin products. This is particularly true in the
Orient, and it is in this part of the world that the greatest opportunity exists for
c. Quality Control. The laxity with which fruits and vegetables are grown,
processed, and distributed has never been justified. They have always been, and
continue to be, a major factor in disease transmission. A considerable reduction in
disease and suffering will be made when fruits and vegetables are eliminated as
vehicles for disease transmission. Such an eventuality is not within our sight, so it is
essential that all members of the military veterinary service be well versed in the
microbiology of fruits and vegetables.
MD0703
2-10