Effects of Sulfide Flavors on AHL ‐Mediated Quorum Sensing and Biofilm Formation of Hafnia alvei

In this study, 10 different sulfide flavor compounds commonly used as food additives were screened for antiquorum ‐sensing activity. Among these, diallyl disulfide (DADS) and methyl 2‐methyl‐3‐furyl disulfide (MMFDS) were found to exert the strongest inhibition against violacein production inChromobacterium violaceum 026, the tested biosensor strain. DADS and MMFDS also inhibited the growth ofHafnia alvei H4, yielding MIC values of 48 and 41.6 mM, respectively. In addition, DADS and MMFDS also inhibited the ability ofH. alvei H4 to produce acyl ‐homoserine lactone as demonstrated by the reduced level of C6‐HSL in the supernatant of DADS‐treated culture. At concentrations corresponding to 1/4 MIC, DADS, and MMFDS inhibited the swarming ability ofH. alvei H4 by 73.50% and 76.43%, respectively, while having virtually no effect on cell growth. The same concentrations of DADS and MMFDS also completely inhibited the formation of biofilm. These antiquorum sensing effects of DADS and MMFDS involved changes in the expression of the quorum ‐sensing genesluxI andluxR. Quantitative RT ‐PCR analysis showed that the mRNA levels of both genes were significantly reduced by DADS and MMDFS at concentrations below their MICs. However, further test using a mutant strain ofH.alvei lackingluxR (ΔluxR) revealed significant reduction inluxI mRNA level upon treatment of the strain with DADS or MMDFS, but no change inluxR mRNA level occurred when aluxI‐lacking mutant (ΔluxI) was ...
Source: Journal of Food Science - Category: Food Science Authors: Tags: Food Microbiology & Safety Source Type: research