Antilisterial activity of lactose monolaurate in milk, drinkable yogurt and cottage cheese

Lactose monolaurate ( LML ) was previously found to be an antimicrobial against L isteria monocytogenes in culture medium at concentrations between 3 and 5 mg ml −1 . In this study, the microbial inhibitory activity of LML in dairy products inoculated with a 5‐strain cocktail of clinical isolates of L . monocytogenes was investigated. Addition of LML at a concentration of 5 mg ml −1 resulted in 4·4, 4·0 and 4·2 log reductions in 0·5% fat, 1% fat and 3·25% fat milks, respectively; 4·1, 4·4, and 3·5 log reductions in nonfat, 1% fat, and 1·5% fat yogurts, respectively; and 4·0 log reductions in both nonfat and 2% fat cottage cheese. The inhibitory effect of LML was only observed at 37° C and not 5° C . Experiments suggest that both the lauric acid and the esterified lactose moiety of LML play roles in the growth inhibition. Significance and Impact of the Study A novel sugar ester, lactose monolaurate, inhibited the growth of a five‐strain cocktail of L isteria monocytogenes in milk, yogurt and cottage cheese. This is the first report of the use of a sugar ester to inhibit the growth of L isteria in food systems.