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  April 2, 2001

Research on Keeping Bacteria at Bay
Will Help Food Last Longer

Claudia Koerting was exuberant. Her samples of processed cheese, which had not been properly refrigerated for weeks, were still fresh and free of bacteria, a testament to her months of effort. It was a marked difference from what she had watched occur earlier in the year.

"When I first inoculated the cheese with bacteria, they took off. They were very happy bacteria," she jokes.

The bacteria, however, are no joking matter. Koerting has been working with the bacterium listeria, which sometimes makes its way into food products and is capable of causing serious illness in humans. It is also extremely hard to kill.

On this particular morning, though, Koerting was able to laugh because, after experimenting with a variety of chemical compounds in multiple combinations, testing them at different temperatures and with varying levels of the chemicals, she had come upon a combination that was holding the bacteria at bay for a third week - 10 times longer than normal. The chemicals she used are regarded as safe by the federal Food and Drug Administration, and the concentrations she used were well below the FDA's acceptable maximum standards. Most of them, in fact, are natural products.

Koerting's work could result in savings of hundreds of thousands of dollars throughout the food services industry. And, for researchers at Nestle, the world's largest food distribution company and the sponsor of Koerting's research, her work could save money and keep the company on top of the food marketing pyramid, as scientists around the world search for ways to limit or eradicate the dangers inherent in food products.

"Salmonella, E-coli, listeria. We've all heard stories of outbreaks of disease, and we're all trying to limit the dangers," says Koerting, a research associate in the Department of Nutritional Sciences. "Microorganisms are present in food, including meats, poultry, vegetables, dairy - the whole range - from the time of harvest, and further contamination may be possible throughout handling, during processing and packaging."

The different types of bacteria that may be present include pathogens, potential pathogens and spoilage bacteria. "For some of these bacteria it's enough to control their numbers," she says. "For others, it's imperative they be eliminated."

Because the work involves pathogens, Koerting's research is performed in the Department of Pathobiology's diagnostic testing laboratory.

UConn's involvement with NestlŽ began in 1998, when a representative of the firm's New Milford-based research division visited department head Carol Lammi-Keefe to explore potential partnerships between the company and the University. After a little more than a year of discussions, NestlŽ and UConn joined forces to investigate ways to extend the shelf-life of foods. What was a one-year partnership was extended last month for another year.

"We like to have partnerships with universities," says David Collins-Thompson, NestlŽ's group manager for food safety. "It's an opportunity to take up expertise at the university, and it enables us to get work done in many different ways."

The NestlŽ brand covers dozens of well known food products, from Nescafe coffee to Carnation dairy and powdered milk products; from Buitoni and Stouffer's frozen foods to Crosse & Blackwell and Libby's canned foods and sauces; from refrigerated products to chocolate. The brand even includes pet foods, opthalmological products and cosmetics. The brand also includes foods that are delivered to the food services industry and large institutions, including the cheese Koerting is working with.

At UConn, company officials were hoping to find a way to enhance the shelf-life and safety of many of their products, while also improving their taste. It was an assignment Koerting, working with David Benson from the Department of Molecular and Cell Biology, and Malika Meemmongkolkiat, a graduate assistant, welcomed.

"It's fun and exciting because it directly affects our quality of life, and because I'm allowed some creativity" in the experimentatio n, says Koerting. "This research is something that will be used by NestlŽ."

Koerting wants to conduct more tests on the most stubborn bacteria, trying still more combinations at lesser concentrations, before taking her results to the company, probably in a few weeks.

The partnership, says Lammi-Keefe, the department head, helps everybody.

"We're watering the seed and we'll see how it grows," she says. "We're hopeful the relationship will grow. Knowing industry people could open up possibilities for students."

It also gives UConn researchers the opportunity to work with NestlŽ researchers. This broadens the department's science base, Lammi-Keefe says, and provides a way to exchange information with scientists who are working on cutting-edge problems. If UConn researchers can help the company, the collaboration also may lead to further partnerships, she says.

Koerting's work is only one step of many that are used to control food safety. The challenge, she says, is to design a system that can control any dangerous microbes while using the least amount of harsh processing, the least amount of chemicals so as not to affect taste, color and texture, and to be aware of consumer concerns. The system also must be cost-effective.

It is a challenge that Koerting seems to have met.

Richard Veilleux