Lactic-Acid Bacteria Helps Prevent Food Poisoning

Texas Tech University, Lubbock, recently reported on the results of Department of Animal and Food Sciences research into using lactic-acid bacteria to reduce the presence of Salmonella and E. coli O157:H7 in ground beef. The study, led by Mindy Brashears, Ph.D., assistant professor, Department of Animal and Food Sciences, and director of the school's International Center for Food Industry Excellence, reduced levels of the two harmful bacteria by as much as 99.99%. Brashears et al published their findings in the Aug. 2005 issue of the Journal of Food Protection (2005; 68(8):1,587-1,592).

The study investigated the effects of using four different Lactobacillus strains on Salmonella and E. coli bacteria in ground beef. The researchers also sought to determine whether or not the Lactobacillus bacteria would affect sensory characteristics of the beef. Several tests showed dramatic reduction of Salmonella and E. coli over the course of several days of storage at 5 deg. C. The goal was to perform the tests in conditions that simulate meat storage and transfer to and from supermarkets. In one test, after five days of storage, Salmonella was reduced to nondetectable levels. Sensory studies comparing noninoculated ground beef with inoculated samples showed that treatment with Lactobacillus did not affect the flavor or texture of the beef.

"Lactic-acid bacteria are considered good bacteria in that they have a lot of benefits," says Brashears. "They are used to make several products, like cheese, yogurt and sausages. They have a place in nature, and they compete with other bacteria by producing compounds that kill the other bacteria. That is where the concept of using these bacteria to actually reduce foodborne pathogens came from. It is not a new concept, but some of the applications we have developed are unique." The bacteria are meant for use as an additional safeguard in a combined approach to eliminating incidence of Salmonella and E. coli in meat products.

In Dec. 2005, FDA granted the mixture GRAS status for use in beef and poultry products. Although products treated with the bacteria have not yet been released, Nutrition Physiology Corporation, Indianapolis, one of the sources of funding for the project, will reportedly market the product as Bovamine Meat Cultures. Other funding support for the study came from USDA's Beef Checkoff Program and the Texas Beef Council, Austin.

According to the Centers for Disease Control and Prevention (CDC), 40,000 cases of salmonellosis are reported every year. However, since many milder cases go unreported, the actual number of infections could be as high as 30 times that number. CDC estimates that 600 people die annually in the United States from acute salmonellosis.