With more than 30.000 known species, fish form the biggest group in the animal kingdom
that is used for the production of animal-based foods. About 700 of these species are
commercially fished and used for food production. Further, some 100 crustacean and 100
molluscan species (for example mussels, snails and cephalopods) are processed as food for
humans in fish industry (Oehlenschläger & Rehbein, 2009). However, some fishery product
is processed in a modern fish industry which is a technologically advanced and complicated
industry in line with any other food industry, and with the same risk of product being
contaminated with pathogenic organisms (Huss, 1994).
The vast majority of outbreaks of food-related illness are due to pathogenic microorganisms,
rather than to chemical or physical contaminants. As they are generally undetectable by the
unaided human senses (i.e.they do not usually cause colour changes or produce off-flavours
or taints in the food) and they are capable of rapid growth under favourable storage
conditions (Lelieveld et al. 2003). The United States Centers for Disease Control and
Prevention reported that fish and shellfish account for 5% of the individual cases and 10% of
all foodborne illness outbreaks, with most of the outbreaks resulting from the consumption
of raw molluscan shellfish (Flick, 2008)