Food Protection Connection: E. Coli Vaccine for Cows
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(reprinted from Dietary Manager, May 2009)
On March 13, 2009, the USDA granted a conditional license for a new tool in the battle against foodborne illness—a vaccine for cows to prevent infection with E. coli bacteria. The potential is profound. The CDC says that most cases of E. coli or STEC-related illness among people originate in the bodies of cows.
Cows harbor the bacteria in their intestines, which then sheds into the environment. For example, contamination of groundwater and the growing environment with manure can, in turn, contaminate fresh produce. Cattle themselves do not experience illness from the bacteria. Danger steps in only when the bacteria transfer to the human food supply.
Of course, beef itself is also a major concern. During slaughter, bacteria from cows’ intestines can contaminate the muscle (the “food” part of a cow). In a meat processing plant, contamination from even a small percentage of cattle can spread to large batches of meat handled in a high-volume plant. Ground beef in particular tends to “pool” large quantities of meat, potentially spreading the contamination.
In people, an E. coli infection leads to bloody diarrhea and painful abdominal cramps, as well as the risk of hemolytic uremic syndrome (HUS) several weeks later. A serious after-effect of the foodborne illness, HUS strikes in five to 10 percent of E. coli cases, leading to anemia and renal failure— a life-threatening condition. Foodborne illness with E. coli affects about 70,000 US citizens every year. About 40 percent of individuals who die from E. coli infections are nursing home residents, according to the CDC (Morbidity and Mortality Weekly Report, March 17, 2000).
More About the Vaccine
The vaccine is basically a protein that generates an immune response in the cows. The vaccine works by preventing iron absorption by E. coli bacteria in the cows’ intestinal tracts. Just as for people, iron is an essential nutrient to the bacteria. Without iron, they can’t thrive.
Researchers studying the E. coli vaccine at West Texas A&M University noted 85 percent less “shedding” of E. coli bacteria among vaccinated cows, and said that even among shedders, bacterial counts were reduced by 98 percent.
The USDA granted the conditional license to Epitopix, LLC, of Willmar, MN. A “conditional license” status allows for further studies over a one-year period, based on safety data already presented. Officials explained that a conditional license is granted when there is a “special circumstance.” In this case, the special circumstance is that E. coli is a major food safety challenge, and so far, we have no comparable tools for controlling E. coli in cattle. Through commercial application to companies whose names have not been disclosed, we may hope to see a downward trend in E. coli incidence in the food supply.
A few days after the vaccine announcement, USDA officials also announced a new, higher level of testing for E. coli in ground beef. The focus will be on high-volume beef processors, i.e., plants that produce more than 250,000 pounds of ground beef each day. Weekly data will be available online, and the USDA will be summarizing findings on a quarterly basis. This will give everyone a measure of how we are doing in reducing contamination in the food supply.
In Canada, another company, Bioniche Life Sciences, Inc., launched an E. coli vaccine for cattle in October, 2008 (Econiche™).Tests conducted by Bioniche Life Sciences on 3,683 cattle showed that just under three percent of vaccinated cows harbored E. coli, as compared with about 17 percent of unvaccinated cows. The Canadian Food Inspection Agency approved the vaccine in October, 2008.
E. Coli or STEC?
E. coli O157 was first identified as a pathogen in 1982, according to the CDC. E. coli bacteria form a toxin, known as Shiga toxin. The resulting foodborne illness is a combination of infection (with the bacteria) and toxicity (from the Shiga toxin). STEC stands for Shiga toxin-producing E. coli, the most common culprit in E. coli illness.
According to the CDC, the most commonly identified STEC in North America is E. coli O157:H7. However, other types of E. coli caused similar illness. They are labeled “non- O157 STEC.” Because they’re less common, they are also less understood, says the CDC.
The vaccine is basically a protein that generates an immune response in cows. The vaccine works by preventing iron absorption by E. coli bacteria in the cows’ intestinal tracts.
How is the pathogen transmitted? The CDC explains, “Some foods are considered to carry such a high risk of infection with E. coli O157 or another germ that health officials recommend that people avoid them completely. These foods include unpasteurized (raw) milk, unpasteurized apple cider, and soft cheeses made from raw milk. Sometimes the contact is pretty obvious (working with cows at a dairy or changing diapers, for example), but sometimes it is not (like eating an undercooked hamburger or a contaminated piece of lettuce). People have gotten infected by swallowing lake water while swimming, touching the environment in petting zoos and other animal exhibits, and by eating food prepared by people who did not wash their hands well after using the toilet. Almost everyone has some risk of infection.”
Standard Operating Procedures
With the anticipation of enhanced control in the food supply, dietary managers must continue to scrutinize and monitor standard operating procedures that help control the E. coli hazard in the foodservice segment of the farm-to-fork food cycle. Effective controls include:
- Implement and enforce an employee health policy consistent with applicable health regulations.
- Enforce handwashing. Keep in mind that an individual who has had STEC can continue shedding bacteria for up to several months.
- Work with suppliers to ensure the safest possible food supplies are entering the operation.
- Wash fresh produce before use, and ensure that cut produce is held at or below 41°F. Remember that at warmer temperatures, bacteria counts can double in as little as 20 minutes.
- Prevent cross contamination.
- Cook ground beef products to established time and temperature standards (155°F for at least 15 seconds, per the current FDA Food Code), and use a reliable thermometer to verify compliance.
- Hold hot foods at or above 135°F (or the regulatory standard that applies to your operation).
From the farm to the foodservice operation, everyone plays a role in ensuring the safety of daily meals. Dietary managers and every employee working in on-site food service are each essential “links in the chain” of food protection.
Sue Grossbauer, RD, author of several books, is a regular contributor to DIETARY MANAGER magazine.