E.coli O157:H7 was one of the pathogens studied by the US Department of Agriculture (USDA)’s Agricultural Research Service (ARS) at the agency's Western Regional Research Center in Albany, California.
Possibly carcinogenic heterocyclic amines, MelQx and PhIP that can be formed during cooking of meats were also studied.
High levels of E.coli O157:H7, along with the plant extract, spice, or herb of interest, were added to the ground beef patties, according to the researchers.
Patties were then cooked on a griddle until the meat’s internal temperature reached 114°F, then flipped and cooked another five minutes until the internal temperature reached the recommended 160°F.
Olive powder reduction
Amine data showed that olive powder reduced MeIQx by about 80% and PhIP by 84%.
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 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.
An olive processing coproduct, olive powder was one of two dozen plant extracts, spices, and herbs that were evaluated for their potential to combat E.coli O157:H7 and to retard formation of heterocyclic amines during cooking of hamburger patties.
Overall, olive powder was the most effective of the plant extracts (olive, apple, and onion powders) that were tested.
Heterocyclic amines formation
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.
However, Mendel Friedman, a research chemist at the centre in California, warned that follow-up studies are needed to pinpoint the compounds in olive powder that are responsible for the effects and to determine whether the amount added in the experiments alters the burgers’ taste.
E.coli O157:H7 is a leading cause of food sickness in the US and is blamed for more than 73,000 cases of illness annually.
Many E.coli outbreaks have been traced to ground beef and have led to the introduction of food safety rules designed to reduce the occurrence of this microbe, and non-O157 shiga toxin producing E.coli (STEC) in meats, poultry, and other foods.