Iowa State is helping to find alternatives to using antibiotics in swine by testing a common yogurt culture.

The culture lactobacillus is a probiotic — a substance that promotes the growth of microorganisms — from pigs’ intestinal tracts that may help lower salmonella levels in animals headed for slaughter.

The project is being funded with a $600,000 grant from the U.S. Department of Agriculture and the National Pork Producers Council, with support from PIC International, a swine genetics company, and the Food Safety Consortium.

Isabel Harris, affiliate assistant professor of microbiology, is a co-leader of the project. Harris said Iowa State is a member of the Food Safety Consortium; therefore, there is an emphasis on finding a way to make a safer food supply.

Between two and four million Americans become sick from foodborne salmonella each year. The salmonella levels in the young pigs who were fed lactobacillus in preliminary tests were reduced.

“We’re looking for alternatives to the antibiotics, and eventually the antibiotics will be discouraged and banned,” Harris said. “That is because of the resistant bacteria that will get into humans and make the antibiotics useless.”

There are other alternatives to lowering salmonella levels called bacteriophages, viruses that infect and kill bacteria. Probiotics encourage the growth of bacteria that will control disease-causing bacteria, Harris said.

Results from testing at Iowa State has shown that pigs that had received bacteriophages either orally or by injection had less salmonella than other swine. A benefit to bacteriophages is that the swine could be injected hours before being processed at packing plants, Harris said.

Project Co-leader Hank Harris, professor of microbiology, said the project’s goal is to find alternatives for antibiotics.

“We’re working with new cultures of lactobacillus, but there are existing products that may be effective,” he said. “Our plan is to evaluate them in the next year. We also are working to help the consumer by getting the levels of organisms to drop.”