Released: August 18, 1998
Common Kitchen Spices Kill E. Coli O157:H7
MANHATTAN, Kan. -- Common kitchen spices -- garlic, cinnamon, clove and others -- can kill the most dangerous strain of Escherichia coli, according to research at Kansas State University.
Daniel Y.C. Fung, a food microbiologist with K-State Research and Extension, has confirmed preliminary findings of a study pairing familiar spices with uncooked consumer beef.
The study is the first in the United States that looks at the effect of common spices on E. coli O157:H7. Previous studies have concluded spices kill other foodborne pathogens.
"In the first part of our study, we tested 23 spices against E. coli O157:H7 in the laboratory," Fung said. "We found that several spices are good at killing this strain of E. coli."
Garlic, clove, cinnamon, oregano and sage each killed the bacteria in varying amounts. In the laboratory study, garlic killed the organism completely. None of the other 18 spices tested was successful in killing E. coli O157:H7.
The five bacteria-killers were used in the second part of the study. Scientists introduced approximately 100,000 E. coli O157:H7 bacteria per gram to store-bought ground beef, then separately added the spices.
Again, the spices killed the bacteria.
Of the five, garlic and clove proved best at killing E. coli O157:H7. Garlic was best in the laboratory study, while clove was the best of the spices added directly to ground beef. In both parts of the study, the five spices killed E. coli O157:H7 bacteria in varying amounts.
Scientists have found E. coli O157:H7 present in less than 1 percent of the U.S. food supply, but it is believed to be the most toxic strain of the bacteria. In severe cases, E. coli O157:H7 causes death in humans.
Killing the bacteria is fairly simple. Consumer-awareness campaigns champion cooking ground beef to 71 C (160 F) before serving.
Now, the spice rack is an additional ally. Using their choice of spice, consumers can give themselves extra protection when preparing and handling beef at home.
"People will still have to take care in handling beef and will still have to heat the product," Fung said. "Spice may provide an additional killing effect alongside heat treatment. The exact combination of spice and heat needs to be tested, however. An additional aspect of the research is to extract the active ingredient in these spices that is killing E. coli O157:H7 and understand why it does this."
In the meantime, Fung urges continued emphasis on how consumers cook ground beef.
"Consumers should still heat ground beef to 71 C (160 F)," he said. "At this point, our conclusion is that we soon may be able to say they also can use spice to effectively kill E. coli O157:H7."
Another of Fung's studies combined spices with salami and other fermented sausages. As in his work with ground beef, the spices were able to kill E. coli O157:H7 introduced to fermented sausage. This has special significance for sausage lovers, since some sausage products often are not heated.
"The study is very exciting because people can relate to the spices we're working with," Fung said. "The data show that they are effective in killing this dangerous strain of E. coli."
Fung has been studying microbiology for more than 30 years. He has gained an international reputation as a lecturer on rapid methods and automation in microbiology. He has published more than 500 articles and received the 1997 International Award from the Institute of Food Technologists. He is a fellow of the American Academy of Microbiology and of the Institute of Food Technologists.
In 1995, Fung presented an invited lecture at the Pasteur Institute in Paris during the 100th year commemoration of Louis Pasteur's death.
K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus in Manhattan.
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Pat J. Melgares, News Coordinator
K-State Research & Extension NewsCall Daniel Y.C. Fung at 785-532-1208.
