Growth inhibition effects of ferulic acid and glycine/sodium acetate on Listeria monocytogenes in coleslaw and egg salad

Listeria monocytogenes is a bacterium responsible for food poisoning through ready-to-eat (RTE) food products. In particular, salads are RTE products that lead to many cases of listeriosis. Such concerns have made it necessary to find a method of inhibiting Listeria growth. In this study, coleslaw and egg salads were inoculated with L. monocytogenes, followed by addition of either ferulic acid or ferulic acid + glycine/sodium acetate, and were incubated at 10 °C for a maximum of 5 days. In coleslaw, the addition of 1500 ppm ferulic acid resulted in a 1.5 log CFU/g reduction in L. monocytogenes after 5 days. In egg salad, for 5 days following the addition of 3000 ppm ferulic acid + 1% glycine/sodium acetate compound, no additional L. monocytogenes growth was observed. This study demonstrates that under particular conditions, ferulic acid has anti-bacterial properties against L. monocytogenes. Our results suggest that ferulic acid could be highly useful for inhibiting the growth of L. monocytogenes in salad products.