The bacterium E. coli O157:H7 has once again made headlines in Canada, as multiple people have become infected and have been sickened following presumed contact with contaminated beef.
As a normal resident of cattle feces, E. coli bacteria can contaminate meat products at the time of processing. Removal of the hide and guts are the most common ways bacteria are transferred to meat.
Illness in people ranges from mild, flu-like symptoms to bloody diarrhea, kidney failure and even death.
Reports of food-borne illness, such as those caused by E. coli O157:H7, often go underreported because typically, only the most severely affected people seek medical care.
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Each year in Canada, an estimated 11 million people contract a food-borne illness, including those caused by this E. coli.
Proper cooking kills the bacteria and eliminates the risk of infection. Despite this relatively simple intervention, food poisoning still occurs all too often.
It behooves the cattle industry to control these bacteria prior to meat entering the retail market.
Cattle contract the bacteria primarily through infected water and feed. Since they carry the bacteria without illness, there is no way to identify its presence without testing. It seems as though few cattle are responsible for the majority of environmental contamination.
One study found that 10 percent of cattle in a feedlot contributed more than 95 percent of the total amount of bacteria in the group.
Lately, much attention has focused on preventing or reducing infection rates at the farm and feedlot level.
Provide clean water troughs, and feed off the ground or in bunkers. Avoiding excessively muddy pens, providing bedding and managing manure all contribute to reducing carcass fecal and mud tags.
Feces and mud on the hide can be a major source of infection during skinning.
Debris on the brisket hair is the most problematic as this is typically where the first cut into the hide is made during the skinning process.
Wildlife such as deer and rats can also carry these bacteria and can spread it to cattle through feed contamination.
A novel control choice is vaccination. Vaccinating for the sole purpose of achieving food safety is a relatively new approach.
Two licensed vaccines are available in Canada. There is good scientific evidence to show that two doses of the vaccine are capable of significantly reducing the amount of this bacteria shed by live cattle.
Just as science supports pre-conditioning (weaning, vaccination, and deworming) prior to shipping calves, the economic benefits of E. coli vaccines to cow-calf producers may not be realized unless those calves are bought at a premium.
Widespread vaccination against E. coli could reduce the number of meat recalls, human illness and processing plant closures; but for producers, such a program would require direct economic incentives.
Enhanced consumer confidence would have trickle-down effects to the whole industry.
Another perhaps less obvious benefit to vaccinating feedlot cattle is a reduction in the amount of bacteria in the manure. This reduces the potential that water and other non-meat products may be inadvertently contaminated by feedlot runoff. Contaminated vegetables and fruit are the second most common source of infection in people, following meat.
The hygiene interventions designed to control all bacteria in processing plants are effective in controlling this special strain.
Interventions to reduce E. coli will also decrease contamination with the other important food-borne bacteria such as listeria and salmonella.
Certainly, processing plants have in important role to play in reducing meat contamination.
However, by decreasing the amount of dangerous bacteria entering the processing system, internal controls can be more effective.
