Antibacterial Efficacy of Essential Oils and Sodium Nitrite in Vacuum processed Beef Fillet

Background and Objective: Minimizing the exposure to nitrate and nitrite and therefore reducing the level of potentially carcinogenic nitrosamines is desired due to the strong public demand and political controversy around this issue in many countries. The present study was designed to investigate antibacterial activity of five different types of essential oils alone or in combination with different concentrations of sodium nitrite. Material and Methods: Five types of essential oils Zataria multiflora Boiss, Satureja bachtiarica Bunge, Rosmarinus officinalis L., Mentha pulegium, and Origanum vulgare L were used in the experiments. NaNO2 in concentrations of 0, 100, and 200 mg kg(-1) were used to study the growth inhibition of Clostridium spp. inoculated in vacuum processed beef fillet. Essential oils were analyzed by gas chromatography-mass spectrometry. Antimicrobial activity against vegetative cells of Clostridium perfringens and Clostridium sporogenes were primarily done by disc diffusion method and minimum inhibitory concentration of essential oils against vegetative cells were determined by broth macro dilution. Sensory evaluation of the uninoculated cooked vacuum processed beef fillet samples with three essential oils with higher antibacterial activity against the more resistant Clostridium spp. was done Results and Conclusion: Among the examined Essential oils Satureja bachtiarica Bunge showed the most inhibition effect on Clostridium perfringens (4.1 mg ml(-1)) and Clostridium sporogenes (5.5 mg ml(-1)) followed by Zataria multiflora Boiss, Origanum vulgare L., Mentha pulegium and Rosmarinus officinalis L. The antimicrobial activity of essential oils against Clostridium spp. was increased in combination with sodium nitrite. It can therefore be assumed that the combination of these two additives could have significant repercussion in the control of Clostridium perfringens and Clostridium sporogenes in vacuum processed beef fillet samples without compromising the organoleptic properties. The best result was achieved by the combination of 100 mg kg(-1) sodium nitrite and 1.1 % v w(-1) Satureja Bakhtiarica Bunge which could inhibit the growth of Clostridium species. The results of the current study showed that the essential oils of interest have had drastic effects on clostridium inhibition and could be used in the meat industry especially for sausages due to their impact on technological, microbiological and sensory properties.