g. Flavor Changes. Even though you, the 91R20, will NOT taste the product,
you should be aware that the following flavor changes have been associated with
h. Common Spoilage Organisms. The most common type of spoilage
organisms in fish are gram-negative psychrophilic bacteria. The chief genera of this
group are Pseudomonas and Achromobacter. These organisms cause slime formation,
discoloration, and putrefaction of the product.
i. Honeycombing. A condition called honeycombing is found in canned tuna
and salmon. It is caused by gas-forming bacteria present prior to canning. This is
indicative of decomposed fish being utilized in the canning process. It is evidenced by
small pitted holes in the surface flesh, which may extend through two or more layers. It
can also be detected as a sharp taste during a sensory evaluation.
j. Pink or Red Oysters. A pink- or red-colored oyster indicates a deteriorative
condition due to the growth of yeast at 0F (-17.8C) and below. The change in color
starts as pinpoint specks. When the oyster is thawed, both the meat of the oyster and
the liquid will become uniformly red. This can also be caused by the oysters eating
small microscopic animals called dinoflagellates. Red pigments accumulate in the liver
and give the oyster a pink or red color.
k. Green-Gilled Oysters. Green-gilled oysters represent another condition that
may be observed. This condition is caused by the accumulation of a pigment in the gills
and mantle. The bluish or greenish pigment is derived from certain types of diatoms.
Diatoms are a family of minute algae upon which the oysters feed. The pigments are
temporarily stored in the blood cells. These blood cells fill up the blood vessels of the
gills and mantle. The color will be more evident in the gills than in any other area of the
l. Cotton or Milky Shrimp. A condition known as cotton or milky shrimp may
be observed during the inspection of shrimp. It is due to parasitic protozoa
(Microspordia). The flesh of the shrimp becomes soft and gelatinous and reminds one
of a puffed-up piece of cotton or cottage cheese curds.
m. Fish Steaks and Fillets. Filleted and steaked fish are particularly
susceptible to the deleterious effects of bad handling. This is because the naked fish
provides an excellent medium for bacterial growth. Theoretically, a fillet carefully
prepared from a fresh fish should be nearly sterile; all bacteria are initially present only
on the exterior surfaces of the fish. However, filleting knives, tables and boards,
filleter's gloves, wash water, and so forth, rapidly accumulate large populations of bacteria if
proper sanitary precautions are not observed. A summary of the condition
characteristics of fresh, stale, and putrid fish may be found in figure 3-1. Those
characteristics that apply to fillets and steaks are marked with an asterisk.