Good bacteria a blow to foodborne pathogen's gut


FAYETTEVILLE, Ark.—Scientists from the U.S. Department of Agriculture's (USDA) chief scientific research agency have found several promising intestinal bacteria that could protect live chickens from salmonella, campylobacter and other pathogens that cause foodborne illnesses in people who eat poultry.

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Annie Donoghue (right), a poultry physiologist at Agricultural Research Service's (ARS) Poultry Production and Product Safety Research Unit, is leading a team of ARS and University of Arkansas researchers in finding new, healthful bacteria that, when fed to live birds, help them resist harmful pathogens and grow more efficiently.

According to the USDA, pathogens like salmonella can be found on several kinds of food, but especially on raw meat, eggs, dairy products and seafood. It is blamed for 1,000 deaths every year and 40,000 cases of salmonellosis.

According to researchers, preventing contamination means eliminating pathogens from taking hold inside the intestinal tracts of the live birds. ARS scientists are getting a better understanding of how live beneficial bacteria, or probiotics, influence the intestinal microbial environment as well as how it interacts with other bacteria. Probiotics contribute to the intestinal tract's health and balance.

Using a concept known as competitive exclusion, probiotics are fed to newly hatched chicks. Once inside, the probiotics occupy sites in the young bird's intestinal tract where the pathogens would normally attach and grow. Since probiotics get there first, they reduce the opportunity for pathogenic bacteria to become established in newly hatched chicks when they are most susceptible to infection.

The team has already screened more than four million intestinal isolates to come up with several promising probiotic combinations. The University of Arkansas and ARS have filed a patent on the selection techniques.

By using pre-selected "good" microbes, researchers hope to produce inexpensive, identified bacterial cultures with the ability to reduce or exclude specific pathogens and enhance enteric health in poultry. They have developed multiple in vitro selection systems for identifying potential probiotics. These new selection techniques make probiotics production less expensive. This could lower the price of poultry and make it less likely to be a source of foodborne illness.