Synergistic effects of nisin and thymol on antimicrobial activities in Listeria monocytogenes and Bacillus subtilis

Nisin Z and thymol were tested, alone and in combination, for antibacterial activity against Listeria monocytogenes ATCC 7644 and Bacillus subtilis AT CC 33712. The antibacterial effect of nisin Z, produced by Lactococcus lact is KE3 isolated from the traditional Moroccan fermented milk, was greatly p otentiated by sub-inhibitory concentrations of thymol in both bacterial str ains. Our data showed that the concentration of nisin required for effectiv e control of food-borne pathogenic bacteria could be considerably lowered b y the use of thymol in combination. The use of low concentrations of nisin could lead to a less favourable condition for the occurrence of nisin-resis tant bacterial sub-populations. (C) 2000 Federation of European Microbiolog ical Societies. Published by Elsevier Science B.V. All rights reserved.