(3) Codworm. A worm which has caused major specification revision is the
codworm (Porracaecum decipiens) which is common to the cod family but also may be
found in haddock, pollock, and lake and ocean perch. It is also found in Pacific Ocean
species. The codworm is the larval form of the roundworm of the seal, which must eat
the fish for the worm to complete its life cycle. The infestation rate is very high for those
fish caught inshore. If the fish are immediately processed and quick-frozen, the worm
will normally be coiled to a diameter of less than 1/4 inch. In conventional frozen fish,
worms tend to migrate towards the surface and can be detected by their light brown
color in 1 1/2-inch lengths. Codworms are not harmful to humans, but they are removed
because they affect the quality of fish flesh presented to consumers.
DETERIORATIVE CONDITIONS OF OYSTERS
a. Spawny Oysters. Spawny oysters can be identified by the presence of a
translucent, milky-colored material. When moderate pressure is applied to the body of a
shucked oyster, this fluid is released from within the oyster. This condition develops
when the water approaches 50 to 70 F during late spring and early fall. On the Pacific
Coast, there is a tendency for spawning to continue throughout the summer months.
Since 2 to 5 percent of Pacific Coast oysters are spawny by this definition, a tolerance
of one spawny oyster per pint has been established for each shipment of oysters.
b. Oysters with Undernourished, Elongated Gills. Undernourished,
elongated gills are a condition that may develop in oysters after the heavy spawning
periods. The condition normally occurs in late spring or early fall. The gills become
thin, watery, and brownish in color. The body is thin and somewhat brownish, not
whitish, the color that would indicate a fat oyster of high quality. There are many other
factors that may produce this condition, for example, salinity of the water, lack of food,
and turbidity of the water.
c. Gaper. A gaper is a dead oyster. The valves are parted and will not close
when the oyster is disturbed. A gaper should not be included in a production lot. Since
the time of death is not known and the degree of deterioration is also unknown,
d. Measuring the pH Level. Measuring the acid value of oyster liquor is a fairly
accurate quality indicator since glycogen is converted to acid at a standard rate. At
origin, fresh oysters must have a 6.2 pH level. At destination, the pH can drop to 6.0.
When performing a surveillance inspection, a pH reading of 5.9 or 5.8 would indicate
immediate issue. A pH below 5.8 is considered sour.