Abstract

Background: Foodborne diseases are considered as major health problems in different countries. Concerns over the safety of some chemical preservatives and negative consumer reactions to them have prompted interest in natural alternatives for the maintenance or extension of food shelf life. In this respect, the combination of a plant essential oil and nisin has used for controlling the growth of foodborne pathogens as natural food preservative using the mathematical model. Objectives: The purpose of this study was to determine the effect of different concentrations of Cuminum cyminum L. essential oil (0, 15, 30 and 45 mu L/100 mL) and nisin (0, 0.5 and 1.5 mu g/mL) combination at different temperatures (10, 25 and 35 degrees C) on growth of Salmonella typhimurium and Staphylococcus aureus in the Brain-Heart Infusion (BHI) broth model. The concentrations of 0 mu L/100 mL for essential oil and 0 mu g/mL for nisin imply the negative control. Materials and Methods: A multivariate variance experiment was performed. To assess the effect of essential oil, nisin and the incubation temperature on growth probability (log P) of S. typhimurium and S. aureus, four concentrations of C. cyminum L. essential oil (0, 15, 30 and 45 mu L/100 mL), three concentrations of nisin (0, 0.5 and 1.5 mu g/mL) and three storage temperatures (10, 25 and 35 degrees C) were considered. Results: The growth of S. typhimurium was significantly decreased by the concentration of essential oil >= 30 mu L/100 mL in combination with nisin >= 0.5 mu g/mL at temperature = 10 degrees C (P < 0.05). Also, in combination of the essential oil >= 15 mu L/100 mL and nisin >= 0.5 mu g/mL at temperature <= 25 degrees C, the growth of S. aureus was significantly reduced (P < 0.05). Conclusions: These results indicate that the combination of essential oil and nisin inhibits the growth of S. typhimurium and S. aureus bacteria and there is the possibility of using them as substitutes for chemical food preservatives. Moreover, the model (log P) in this study can be a good tool for the reduction of microbiological hazards in food industry.