Could Olive Powder Kill E. Coli?

Plant-based compounds such as olive powder may have the power to shut down pathogens like E. coli in food, according to reports from the USDA’s Agricultural Research Service.

Research chemist Mendel Friedman, PhD, has been studying olive powder and other plant compounds (such as apple, onion, and garlic) for many years. In a recent study, highlighted in the May/June 2013 issue of Agricultural Research magazine, Dr. Friedman and colleagues loaded up ground beef patties with E. coli O157:H7, and then mixed in either olive powder or one of the other plant compounds before cooking the burgers to 160 degrees Fahrenheit.

The olive powder was one of the most effective, reducing E. coli levels to below the detection limit. An extract of 1 percent lemongrass oil also reduced the pathogen’s levels to below detection limits, but olive powder had the substantial added benefit of reducing two carcinogenic amines (formed when burgers are cooked to the recommended degree of doneness) by approximately 80 percent. That finding, which first appeared in the March 2012 edition of the Journal of Agricultural and Food Chemistry, is the first to show that olive powder has this 1-2-3 punch.

“Many of these essential oils and spices also happen to be antimicrobial, having the effect of disrupting the bacteria’s cell membrane,” says Dr. Friedman. “This is particularly helpful because many of the pathogens have developed resistance to the ‘medical’ antimicrobials, and it appears that for now, these natural compounds also work against antibiotic-resistant bacteria.”

Another plus: Consumers are much less likely to object to foods that have been treated with a plant extract than those containing antibiotics. “You could potentially add olive powder to animal feed, instead of antibiotics,” Dr. Friedman suggests.

The next step, Dr. Friedman says, is to test the various plant extracts at different concentrations, and in different combinations, in a number of types of food beyond just ground beef. “Of course, we want to be able to use the lowest amount possible in order to minimize any effect on taste,” he comments. “And we also want to see what happens when we combine some of these antimicrobial plant substances. There might be synergy in using two or three of them together.”