The first large outbreak of cryptosporidiosis from a contaminated food occurred in 1993 and was attributed to fresh-pressed apple cider. Cryptosporidium is found in feces of infected mammals and has been transmitted through contaminated water and food. Norwalk virus Norwalk viruses cause sporadic and epidemic gastrointestinal disease with dehydrating diarrhea. An estimated 181,000 cases occur annually in the USA with no known deaths. Outbreaks have been caused by oysters contaminated by sewage dumped overboard by oyster harvesters and recreational boaters.
Consumers make mistakes preparing food at home that increases the risk of foodborne illness.
Foodborne illnesses have also been traced to commercial food establishments. Many food establishments do not know that the pooling and undercooking of eggs can increase the risk of Salmonella enteritidis . Institutional environments increase the risk of foodboren infection.