Link Between E. coli And Distillers' Grains Studied By Researchers

Main Category: Infectious Diseases / Bacteria / Viruses
Also Included In: Nursing / Midwifery;  Public Health;  Biology / Biochemistry
Article Date: 22 Aug 2008 - 3:00 PDT

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A research team headed by Kansas State University E. coli O157:H7 expert T.G. Nagaraja has been tapped by the U.S. Department of Agriculture to study both the connection between feeding distillers' grains and E. coli 0157:H7 in cattle and several strategies to reduce the presence of the naturally occurring pathogen in the animals.

The group has received a $939,220 National Research Initiative in Food Safety grant. Nagaraja, a university distinguished professor of microbiology, said the issue of meat safety is receiving full attention from both researchers and the meat industry and is being addressed.

"This research project will greatly enhance our understanding of the exact relationship between dietary distillers' grains and E. coli 0157:H7 in cattle, as well as provide us with an opportunity to look at novel ways to mitigate the potential risks of feeding this valuable co-product," Nagaraja said.

Distillers' grains are a byproduct of ethanol produced from cereal grains that are used in cattle feed. They are rich in fiber, energy and protein.

The research team will look at ways to reduce the amount of E. coli O157:H7 present, such as administering a probiotic, an experimental vaccine and feeding brown seaweed, a plant shown to have an effect in reducing E. coli O157:H7 prevalence in cattle. In addition, they also will study whether feeding varied amounts of the distillers' grain or making it dry or wet has an effect on the prevalence of E. coli O157:H7 detected in the feces.

Along with Nagaraja, the research team includes K-State professors David Renter, Mike Sanderson and Dan Thomson, and doctoral student Megan Jacob.

The grant builds upon the long history of K-State researchers focusing on food safety. An example of that work that has direct application to the consumer comes from meat scientist Melvin Hunt.

"Despite care in food processing and provision, there is a possibility that food can become contaminated with potentially harmful bacteria," Hunt said. "Occasional recalls of potentially contaminated ground beef in recent years are a sign that safety checks are working -- hamburger lovers do not need to give up their favorite food."

Consumers need to be mindful that recommendations for cooking ground beef have changed. Generations have been brought up to think that when ground beef browns, it's cooked. That's no longer true, Hunt said.

In the mid-1980s, K-State meat science researchers were asked to study the possibility of reducing the percentage of fat in ground beef without compromising taste and texture.

As the K-State researchers studied ground beef with differing proportions of fat, they observed how the meats cooked and noted that some ground beef browned prematurely, before it had reached the safe-to-eat temperature of 160 F.

The color of meat depends on the oxygen in the muscle cells, Hunt said. As an example, he explained that fresh ground beef is bright red because oxygen is incorporated into the meat as it is ground. As the meat ages, it loses oxygen, which causes the color to change. The oxygen in the muscle is carried by myoglobin, which is similar to hemoglobin that carries oxygen in humans.

Observations during the study prompted researchers to recommend that temperature -- not color -- should be used as a test for doneness, Hunt said.

In a restaurant, consumers are advised to order a ground beef patty cooked to at least medium, or 160 F. At home, they are advised to check end-point temperature with a meat thermometer.

"Using a meat thermometer is the only sure way to tell if meat is properly cooked," Hunt said.

The K-State researchers are among the more than 150 K-State experts working in the arena of food safety, animal health and agricultural health. More than $70 million has been dedicated to research in these areas since 1999.

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Article adapted by Medical News Today from original press release.
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Source: T.G. Nagaraja
Kansas State University