Tea Time Means Danger for Listeria, E. coli

Released: 2-Mar-2007 12:00 AM EST
Source Newsroom: University of Arkansas, Food Safety Consortium
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Newswise — Take a serving of extracts from green tea or Jasmine tea, mix in some wildflower dark honey and you have something more useful than a drink. It's actually a scientific mixture that can be used to reduce pathogenic bacteria in meats.

"Our results indicated that Jasmine tea with honey and green tea with honey had the highest antimicrobial activity," said Daniel Fung, the Kansas State University food science professor who supervised the research for the Food Safety Consortium.

The tests were first conducted in a liquid medium and found that the tea extract and honey treatments caused significant reductions of Listeria monocytogenes and E. coli O157:H7 bacteria. "That's not surprising," Fung said. "In liquid medium, it's easier for the compounds to interact with the organisms in liquid."

Then Fung, working with KSU researchers Beth Ann Crozier-Dodson and Laura Munson, moved on to food, which can be a more difficult medium when seeking to cause the type of reaction among the compounds that will inhibit pathogens.

The results were good. Treating turkey breast slice with combinations of Jasmine tea extract and wildflower dark honey reduced Listeria monocytogenes by 10 to 20 percent. Similar reductions of the pathogen were recorded when applied to hot dogs.

The most successful reductions in hot dogs were in those that had been commercially treated with sodium lactate, potassium lactate and sodium diacetate. "In that type of hot dogs, it has much more suppressive effect than in some of the hot dogs without those compounds," Fung explained. "There is a synergistic effect of the tea and honey along with those compounds with lactate already in the hot dog."

One of the beneficial side effects of the treatment is shelf life. Fung noted that the experiments showed the hot dogs were still showing reduced levels of pathogens 14 days after the application.

With such favorable results from the tests, Fung is thinking ahead to future possible applications as a surface wash for meat during processing as well as way to improve the safety of ready-to eat meats and vegetables.

"We're thinking of using tea to wash carcasses because of its natural compounds," he said. "" If you can use tea or honey to wash carcasses instead of lactic acid, you can use a natural compound on the surface of meat."


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