Scientists’ Secret Ingredient for a Better Burger

Chances are that you—or whoever’s the “grillmaster” at your house—have your own “secret ingredient” for making grilled burgers taste even better. But it might surprise you to know that Agricultural Research Service (ARS) scientists and their university colleagues also are working on secret ingredient for a better burger, although their interest focuses on food safety rather than flavor.

They’ve been testing the capacity of olive powder, a byproduct of olive processing, as a weapon against Escherichia coli O157:H7, and the powder’s potential to retard the formation of undesirable substances called heterocyclic amines while the patties are being grilled.

Studies have shown that olive powder has potential to suppress the foodborne pathogen E. coli O157:H7 in hamburger patties and to retard the formation of potentially carcinogenic heterocyclic amines that can form when the burgers are cooked.

E. coli O157:H7 is a well-known cause of food poisoning in the United States and is blamed for about 60,000 cases of illness annually. In recent years, E. coli outbreaks have been traced back to a wide variety of foods ranging from ground beef to hazelnuts to lettuce. Heterocyclic amines are a concern because they can inadvertently be formed when patties are cooked to the degree of doneness recommended for killing microbes such as E. coli. The two amines studied in the burger experiment, MeIQx and PhIP, are on the National Toxicology Program’s roster of possible carcinogens.

The scientists added high levels of E. coli O157:H7, along with plant extracts including olive powder, apple powder and onion powder, to ground beef patties. Then the patties were grilled to the recommended internal temperature of 160 degrees Fahrenheit.

Overall, the olive powder was the most effective of all the plant extracts tested. The results showed that the olive powder reduced MeIQx by about 80 percent and PhIP by 84 percent.

The scientists still need to pinpoint the compounds in the olive powder that are responsible for stopping the microbes and the amine formation, and to determine whether the amount of olive powder added in the experiments alters the burgers’ taste.

This isn’t the first discovery of olive powder’s ability to kill foodborne pathogens. But this study, conducted at ARS’ Western Regional Research Center in Albany, Calif., may be the first to show olive powder’s power in concurrently suppressing three targets of concern: two amines and a pervasive E. coli.