Some ocean bacteria (species of
Photobacterium and Vibrio) produce light
by way of a particular chemical reaction
that releases photons, and can cause shrimp
and crab to glow in the dark! So far, these
luminescent bacteria appear to be harmless
to humans, though some can cause disease
in the crustaceans. Their glow indicates
that the crustaceans are laden with bacteria
and thus not pristinely fresh.
But by far the most important defense
against spoilage is temperature control. The
colder the fish, the slower enzymes and
bacteria do their damage.
Refrigeration: The Importance of Ice For
most of the foods that we want to store fresh
for a few days, the ordinary refrigerator is
quite adequate. The exception to the rule is
fresh fish, whose enzymes and microbes are
accustomed to cold waters (p. 189). The key
to maintaining the quality of fresh fish is ice.