Abstract: This study investigated the effects of two quorum sensing inhibitors, D-ribose and cinnamaldehyde, on the microbial community structure in Sichuan pickle by high throughput sequencing and it further analyzed their effects on the physiological behavior on specific spoilage bacteria isolated from Sichuan pickle. The results revealed that D-ribose significantly increased the relative abundance of Lactobacillus from 19.38% (the second highest) to 80.10% (the highest). In addition, Staphylococcus equorum (OTU4), Lactobacillus ginsenosidimutans (OTU6), Propionibacterium acnes subsp. acnes (OTU8) and Lactococcus lactis subsp. lactis (OTU9) were not detected in D-ribose-treated samples. In contrast, cinnamaldehyde had no significant effect on the microbial community structure. Growth curves showed that D-ribose had no influence on the growth of specific spoilage bacteria but cinnamaldehyde inhibited their growth. Moreover, they both significantly decreased the biofilm formation of spoilage bacteria. Compare with their control counterparts, after being treated with D-ribose and cinnamaldehyde, the biofilm formation of Pantoea calida was reduced to 11% and 10%, respectively; the biofilm formation of Pantoea ananatis was reduced to 21% and 17%, respectively; the biofilm formation of Pantoea anthophila was reduced to 11% and 9%, respectively; the biofilm formation of Staphylococcus saprophyticus was decreased to 11% and 15%, respectively. This study provides useful information for further exploration of the regulatory mechanism of the microbial diversity in Sichuan pickle, and also provides new ideas for developing new preservation technologies for fermented foods.

Key words: Sichuan pickle, D-ribose, cinnamaldehyde, microbial diversity, biofilm