"Those that were fed our probiotics had a 50 to 70 percent reduction (in E.coli)," said Mindy Brashears, an assistant professor in animal science at Texas Tech University and one of the researchers.

"It gives us another hurdle to put in place before the E.coli gets to the consumer," she said of the feed supplement.

The results were based on studies this past summer by Texas Tech researchers and were announced at the teleconference, which was sponsored by the American Meat Institute Foundation.

Probiotics are lactic-acid producing bacteria and are already used in livestock feed as a means to improve weight gains in cattle.

"It is commercially available now to improve animal performance, but it is not sold on the basis to reduce E.coli in the animal," said Brashears.

Food and Drug Administration approval will be needed before it can be touted as an E.coli-reducing feed ingredient, she said.

E.coli O157:H7 is a deadly bacteria found in the intestinal tracts of animals and can often contaminate beef during slaughter. It has been responsible for illnesses in humans and children and the elderly are most susceptible.

"We've known for the past 100 years that lactic acid bacteria kills food-borne pathogens, but we don't know what's going on in the animal," said Brashears.

Researchers think the lactic acid bacteria reduces E.coli by either killing it, preventing it from receiving the necessary nutrients, or preventing it from attaching to an animal's intestines, Brashears said.

The probiotics in the feed costs about one cent per animal per day, but that cost is offset by improved weight gains in the cattle, AMI researchers said.