Antibacterial Effects of Benzyl Isothiocynate, Nisin and Thymol Compounds

In order to enhance the antimicrobial effect of natural active ingredient on food-borne pathogen,such as Staphylococcus aureus and Escherichia coli,benzyl isothiocynate,nisin and thymol were mixed according to the chessboard method in this study,and the antibacterial effects were assessed using a FICI model based on a non-parametric model of Loewe additivity model and ΔE model based on non-parametric model of Bliss independence model. Results showed that,FICI value and absolute value of ∑ΔE of BITC-nisin compound were 0.2917<0.5 and 451.74%>200%,respectively,representing strong synergy. FICI value and absolute value of ∑ΔE of nisin-thymol compound were 0.5833>0.5 and 19.73%<100%,respectively,representing weak antagonism. FICI value and absolute value of ∑ΔE of BITC-thymol compound were 1.5000>0.5 and 219.86%>200%,respectively,representing strong antagonism. In a word,statistically significant synergy was found between nisin and BITC in their inhibitory effects on S.aureus ATCC25923,while in the other interactions synergistic antimicrobial effects on S. aureus ATCC25923 or E. coli MG1655 was not significant.