Enhancing the Heat Sensitivity of Escherichia coli O157:H7 in Ground Beef by Monocaprylin

Ground beef is the most popular beef product consumed in the United States. While E. coli
O157:H7 in ground beef has decreased significantly according to government data, there is still
work to be done to prevent foodborne illness. The U.S. Department of Agriculture recommends
that ground beef patties should be cooked to an internal temperature of 160°F, however
consumers tend to rely more on the color and texture of cooked meat as a means of determining
doneness. Unfortunately, premature browning in ground beef can lead to inadequate cooking by
consumers, which can in turn lead to the survival of E. coli O157:H7. When compared to steaks
and roasts, ground beef is especially problematic because of the accelerated oxidation of
myoglobin that occurs as a result of grinding. The grinding process can also lead to a greater
distribution of pathogenic bacteria. The infectious dose of E. coli O157:H7 is very low—two to
2,000 cells—emphasizing the importance of properly cooking ground beef. An antimicrobial
hurdle applied at the end-user level would be prudent to inactivate E. coli O157:H7 and prevent
foodborne illness. <P>

Caprylic acid is a fatty acid present in breast milk, bovine milk and coconut oil and is a foodgrade chemical approved by the Food and Drug Administration as “generally recognized as safe”
(GRAS). Monocaprylin is a form of caprylic acid. Monoglycerides such as monocaprylin have
been hypothesized to act as non-ionic surfactants, which penetrate and get incorporated into
bacterial plasma membranes, thereby altering membrane permeability thus increasing their
sensitivity to heat. Applying caprylic acid to ground beef might help ensure that consumers cook
it to the appropriate level of doneness.