When harvested in a clean environment and handled hygienically
until consumption, fish is very safe. Unfortunately, unhygienic
practices, insufficient refrigeration and sub-standard
manufacturing practices have been at the origin of many
outbreaks of fish-borne illnesses. Fish-borne illnesses can be
broadly divided into fish-borne intoxications and fish-borne
infections (see table below). In the first case, the causative
agent is a toxic compound that contaminates the fish or is
produced by a biological agent in the fish. If the agent is
biological, intoxication will occur even if the agent is dead as
long as it has previously produced enough toxins to precipitate
the illness symptoms. In the case of infections, the causative
agent (bacteria, viruses or parasites) must be ingested alive,
and then it invades the intestinal mucous membrane or other
organs (infection) or produce enterotoxins (toxi-infection). It
is worth noting that, apart from Vibrio species, L.
monocytogenes and Cl. botulinum that are part of