The CDC estimates that 76 million foodborne illness, or food poisoning, cases occur in the United States every year, which means that one in four Americans contracts a foodborne illness annually after eating foods contaminated with such pathogens as E. coli O157:H7, Salmonella, Hepatitis A, Campylobacter, Shigella, Norovirus, and Listeria. Approximately 325,000 people are hospitalized with a diagnosis of food poisoning, and 5,000 die. The estimated costs in terms of medical expenses and lost wages or productivity are between $6.5 and $34.9 billion (Buzby and Roberts, 1997; Mead, et al., 1999).

While most foodborne illness cases go unreported to health departments, nearly 13.8 million food poisoning cases are caused by known agents – 30% by bacteria, 67% by viruses, and 3% parasites (Mead, et al., 1999).

A recent report (2005) released by the CDC in collaboration with the FDA and USDA showed important declines in foodborne infections due to common bacterial pathogens in 2004. From 1996-2004, the incidence of E. coli O157:H7 infections decreased 42 percent. Campylobacter infections decreased 31 percent, Cryptosporidium dropped 40 percent, and Yersinia decreased 45 percent. Salmonella infections dropped 8 percent, but only one of the five most common strains declined significantly. The incidence of Shigella, which is found in a wide variety of foods, did not change significantly from 1996 through 2004. Vibrio infections increased 47 percent.