Reducing Salmonella by 90 Percent in Meat Products

An old technology—bacteriophages—can dramatically reduce Salmonella bacteria in beef, chicken, turkey, and pork products, according to new research by Amilton de Mello, PhD, assistant professor at the University of Nevada, Reno.

“There are a lot of concerns about Salmonella,” says Dr. de Mello, who is from the College of Agriculture, Biotechnology and Natural Resources. He says it’s one of the four major food pathogens worldwide, the others being Listeria, E. coli, and Campylobacter.

Salmonella is one of the most common causes of foodborne sickness in the U.S., linked to an estimated one million illnesses annually, with 19,000 hospitalizations and 380 deaths, according to the CDC. Symptoms of an infection include diarrhea, fever, vomiting, and abdominal cramps. An infection can be fatal in young children and the elderly.

Dr. de Mello turned to bacteriophages, viruses that infect and replicate within bacteria, to add another food safety intervention step to meat processing in addition to temperature controls and organic acids.

“We came up with another hurdle to improve what we have,” he says. “Bacteriophages are found everywhere. They are the most abundant organisms on the planet.”

He says bacteriophages date to the late 1800s, when they were used before antibiotics as a therapy against live bacteria. They harm specific bacterial cells but are safe to humans, animals, and plants, he says, adding that they also add no taste to the meat.

Dr. de Mello says he’s using them in the food industry because they target specific bacteria.

“There’s a need for specific food-industry interventions,” he says. “Bacteriophage activity can minimize the activity of Salmonella.”

Dr. de Mello presented his research at the international American Meat Science Association’s conference June 20-22 in San Angelo, Texas.

He notes that while others have used bacteriophages in food, his work is innovative in that it simulates what the industry does in processing. Most other research, he says, treated the meat with bacteriophages after grinding, not before. Grinding can transfer bacteria from the outside surface of meat to the inside, he says.

Dr. de Mello says he sprayed the bacteriophage on top of the meat and then ground it and tested it.

“We were able to reduce Salmonella by as much as 90 percent in ground poultry, ground pork, and ground beef,” he says. “The results are very encouraging and we’re hoping this can be adopted by the meat industry to increase food safety.”

Dr. de Mello adds, “We tried to simulate real industry applications. We recovered the bacteria to observe in chicken, turkey, pork, and beef. Each bacterium has a specific structure a bacteriophage can attach to. Some bacteriophages attack specific bacteria.”

His next step is to study E. coli and to isolate individual viruses that can attack all E. coli adulterants. That work, he says, will begin next semester.

Dr. de Mello is not working with major processors now, but says he’s received a lot of emails from them expressing interest in the technology. He is working on a paper he hopes to publish by the end of the year.