Antibacterial activity of eugenol and peppermint oil in model food systems

Food borne illness caused by microorganisms is a large and growing public health concern worldwide. Due to increased concerns of food safety and consumer demand for safer additives there is growing interests in use of natural antimicrobial compounds, and essential oils are being explored for food uses. In the present study, we have evaluated the antibacterial activity of eugenol and peppermint oil against two Gram-positive and two Gram-negative bacteria, and both the oils inhibited growth of tested bacteria with minimum inhibitory concentration (MIC) of 0.25% or below. The efficacy of these oils was also tested in model food systems (cabbage and barley) and real food (papaya pulp) during storage. At MIC, the growth of bacteria was similar to control in model foods, however double of MIC was effective in reducing the bacterial growth in both the model systems. For similar reduction in bacterial count in papaya pulp, five-fold MIC of essential oils was required. Due to high inhibitory concentration of essential oils in papaya, their effect on sensory and textural properties of foods needs a deeper study.