Animals infected with viruses and bacteria shed these pathogens in their manure. If groundwater and surface water contaminated by manure is not properly treated and is subsequently used as drinking water, for recreation, or in food processing it presents a public health hazard. High speed processing of livestock can result in meat contaminated as a result of contact with fecal matter and any associated pathogens from the animals’ intestines. Public health experts estimate that there are 11 to 13 million cases of foodborne illnesses in Canada every year.
Pathogens in meat
E. coli 0157
E. coli 0157 is the deadly bacteria that contaminated the water supply in Walkerton. When cattle are fed a ration high in grain their digestive systems become more acidic and more prone to developing bacterial infections, including acid-tolerant E. coli 0157. Meat is contaminated by E. coli 0157 if feces from infected cattle come in contact with meat during processing. When consumed by humans E. coli 0157 produces a toxin that causes food poisoning, kidney failure, and in some cases, death.
Salmonella is another meat borne pathogen. It is commonly resistant to several types of antibiotic which increases the health threat to humans. Industrially raised poultry are more susceptible to salmonella contamination and have a high rate of antibiotic resistance
Campylobacter jejuni is a bacterial infection that causes diarrhea. The main source of contamination is undercooked poultry, although it can occur in any animal products. The study, Campylobacter jejuni—An Emerging Foodborne Pathogen acknowledges an increased incidence of c. jejuni contamination on farms when animals’ immune systems have been compromised, when antibiotic resistance has developed, and during slaughter.
Clostridium difficile is a serious diarrhea disease. In October 2006 there were news reports about the emergence of antibiotic resistant C. difficile in the community—whereas previously it had been considered a disease found only in hospital settings. Scientists in Canada and the United States are exploring the unsettling question of whether C. difficile can be contracted by eating meat after finding evidence of infection in food animals, including dairy calves in Ontario. The bacterium has already been isolated from meat in the retail food system. The study further shows that a strain of C. difficile that has caused severe hospital outbreaks in Quebec, Britain and parts of the U.S. has been found in the feces of dairy calves in Ontario. Earlier U.S. studies have found other strains of C. difficile in piglets."
Listeria monocytogenes is a rare but serious food-borne disease that can survive on food under refrigeration. It is particularly dangerous for pregnant women, as it can result in miscarriage, stillbirth or serious illness in the newborn. In the summer of 2008 20 Canadians died from listeriosis caused by contamination at Maple Leaf's Bator Road plant. The list of recalled products illustrates how the centralization and concentration of meat processing magnifies food safety risks. Read more about the 2008 listeriosis outbreak.