Synergistic effect of copper and lactic acid against Salmonella and Escherichia coli O157:H7: A review

The number of foodborne outbreaks due to bacterial pathogens such as Salmonella and Escherichia coli O157:H7 have raised concern about the safety of foods. Application of various natural antimicrobial compounds can provide opportunities for the control of pathogenic microorganisms and thus improves food safety and quality. Several researchers in the past have demonstrated antimicrobial properties of copper in different agricultural system. Recent works in our laboratory also showed synergistic effect of copper and lactic acid at low level. However, use of copper as antimicrobial agent in food systems still remains scarce. Our research group is interested in the use of such natural compounds to inhibit the growth of foodborne pathogens. We have used several natural compounds such as organic acids and plant extracts to control the growth of foodborne pathogens. We recently became interested in developing a novel natural system that is effective in controlling pathogenic microorganisms. This system consists of copper in combination with organic acids such as lactic acid. The use of copper at low concentration in combination with lactic acid has been shown to reduce if not eliminate the presence of foodborne pathogens. Therefore, the purpose of this review was to discuss and highlight the wide range of antimicrobial benefits of this new finding. This paper briefly covers possible antimicrobial mechanism of copper, synergistic effect and potential application in food products.