Why do foodborne diseases emerge?
New foodborne disease threats occur for a number of reasons. These include increase in international travel and trade, microbial adaptation and changes in the food production system, as well as human demographics and behaviour: • The globalization of the food supply: A large outbreak of cyclosporiasis occurred in North America in 1996-7 linked to contaminated raspberries imported from South America. • The inadvertant introduction of pathogens into new geographic areas: Vibrio cholerae was introduced into waters off the coast of southern United States when a cargo ship discharged contaminated ballast water in 1991. It is likely that a similar mechanism led to the introduction of cholera for the first time this century into South America in 1991. • Travellers, refugees, and immigrants exposed to unfamiliar foodborne hazards while abroad: International travellers may become infected by foodborne pathogens that are uncommon in their countries. It is estimated that about 90% of all cases of
