Comparison of the Antibacterial Effects of Metabisulfite and Mentha longifolia L. Essential Oil in Giant Freshwater Prawns

Introduction: Using herbal essential oils and extracts as antibacterial agents has attracted great attention for preventing the growth of pathogenic bacteria. The present study aimed to compare the effects of sodium metabisulfite and Mentha longifolia L. essential oil (MEO; 0%, 0.5%, 1%, and 2%) in the growth prevention of Listeria monocytogenes and Escherichia coli O157:H7 in peeled giant freshwater prawns in cold storage for two weeks. Methods: The antimicrobial effects of MEO against L. monocytogenes and E. coli O157:H7 were investigated in-vitro using the disk diffusion method. In addition, the effects of the direct addition of MEO (0%, 0.5%, 1%, and 2%) and sodium metabisulfite (1.25%) to prawn samples were evaluated. Results: The major chemical constituents of MEO were pulegone (47.20%), eucalyptol (22.72%), and menthone (13.44%). The mean diameter of the inhibition zone of MEO against L. monocytogenes and E. coli O157:H7 was determined to be 9.45±0.23 and 6.37±0.02 millimeters, respectively. MEO concentrations of 0.5%, 1%, and 2% significantly reduced the growth of L. monocytogenes and E. coli O157:H7 compared to the control group (P<0.05). However, sodium metabisulfite was more effective than MEO in inhibiting the growth of L. monocytogenes and E. coli O157:H7 in raw freshwater prawns. Conclusion: According to the results, MEO could effectively prevent the growth of L. monocytogenes and E. coli O157:H7 and improve the safety of raw freshwater prawns during prolonged refrigerated storage.