Olive powder may reduce E. coli

Published on: Jul 2, 2013

The potential of olive powder to keep foods safe to eat is getting a fresh look from Albany chemist Mendel Friedman and colleagues at the University of Arizona-Tucson.

An olive processing co-product, olive powder was one of about two dozen plant extracts, spices, and herbs that the team evaluated for their potential to combat Escherichia coli O157:H7 and to retard formation of heterocyclic amines during cooking of hamburger patties.

E. coli O157:H7 is a leading cause of food sickness in the U.S. and is blamed for more than 73,000 cases of illness annually. In recent years, many E. coli outbreaks have been traced back to ground beef and have led to the introduction of stringent new food safety rules designed to reduce the occurrence of this microbe, and six of its relatives, in meats, poultry, and other foods.

Heterocyclic amines are of concern because they can inadvertently be formed when beef patties are cooked to the doneness recommended for helping kill unwanted microbes, such as E. coli. The two amines monitored in the burger experiment, MeIQx and PhIP, are on the National Toxicology Program’s roster of possible carcinogens.

For the study, high levels of E. coli O157:H7, along with the plant extract, spice, or herb of interest, were added to the ground beef patties. The patties were then cooked on a griddle until the meat’s internal temperature reached 114°F, then flipped and cooked another 5 minutes until the internal temperature reached the recommended 160°F.

The amine data showed that olive powder reduced MeIQx by about 80% and PhIP by 84%.

Overall, olive powder was the most effective of the plant extracts (olive, apple, and onion powders) that were tested.

Friedman notes that follow-up studies are needed to pinpoint the compounds in olive powder that are responsible for these effects and to determine whether the amount added in the experiments alters the burgers’ taste.

The ability of olive extracts to kill foodborne pathogens has been reported in earlier studies conducted at Albany, Tucson, and elsewhere. However, the E. coli and amines study, reported in a 2012 issue of the Journal of Agricultural and Food Chemistry, may be the first to show olive powder’s performance in concurrently suppressing three targets of concern -- two major amines and a pervasive E. coli.

Friedman collaborated in the work with University of Arizona co-investigators Yelena Feinstein, Cody M. Havens, Liliana Rounds, and study leader Sadhana Ravishankar.