Studies on the potential usage of mixtures of plant essential oils as synergistic antibacterial agents in foods

Six different combinations of three different essential oil mixtures were studied for their possible synergistic activity against 13 food bacteria in vitro. The individual composition of each essential oil as well as that of the mixture was also determined. The results indicated that there was no apparent synergistic activity exhibited by any of the mixtures used. The use of a highly active essential oil with less effective ones simply diluted out the activity of the strongest component. Although there was lack of synergism, there was usually no great loss of activity when the mixture was used compared with the antibacterial activity of the most potent essential oil in the mix (except where clove and cassia was used); this suggests that mixtures of essential oils could be used in processed foods in order to diminish the odour of each individual component which would have been more apparent at the higher concentration if the oils were used singly. Copyright © 1998 John Wiley & Sons, Ltd.