Antimicrobial activity of essential oils and structurally related synthetic food additives towards Clostridium perfringens

To assess the potential of essential oils and structurally related synthetic food additives in inhibiting the growth of Clostridium perfringens for the control of necrotic enteritis in chickens. The antimicrobial activity of essential oils/compounds was measured by determining the inhibition of bacterial growth. Thirty-three of 66 oils/compounds exhibited >= 80% inhibition. Seven with the highest potency were further studied. The oils/compounds had MIC95 values between 167 and 425 mu g ml(-1). Most of them were tolerant to low pH (2.0) and exhibited minor or no inhibition of Lactobacillus isolates from the chicken intestine. When mixed with chicken ileal digesta, the oils/compounds retained their efficacy against C. perfringens, but had little effect on the total number of lactobacilli and anaerobic bacteria in the digesta. Some essential oils/compounds demonstrated good potential in controlling C. perfringens. This study has identified candidates of essential oils/compounds for in vivo studies for the control of necrotic enteritis in chickens.