Investigation of diverse bacteria encoding histidine decarboxylase gene in Sichuan-style sausages by culture-dependent techniques, polymerase chain reaction-denaturing gradient gel electrophoresis, and high-throughput sequencing

The diverse bacteria encoding histidine decarboxylase gene during the fermentation of Sichuan-style sausages were investigated by culture-dependent techniques, polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), and high-throughput sequencing. All microbial indicators exhibited the advantages of mixed starter culture and the stability of microecosystem was more in the inoculation group than in the control group. DGGE and selected band sequencing were used to investigate the bacterial diversity of these sausages. Weissella were the main lactic acid bacteria (LAB) in the initial fermentation stage, whereas Weissella and Lactobacillus were the dominant bacteria in the later fermentation stage. After sequence alignment analysis, Enterobacter aerogenes and Citrobacter freundi were the two main bacteria encoding histidine decarboxylase gene and could produce histamine. These findings facilitate the better understanding of bacteria producing histidine decarboxylase during sausage fermentation and provide a theoretical basis for the control of histamine-producing bacteria in the process of fermented sausage processing.

Automated summary

This study investigated the diverse bacteria encoding histidine decarboxylase gene during the fermentation of Sichuan-style sausages using culture-dependent techniques, PCR-DGGE, and high-throughput sequencing. The stability of the microbial ecosystem was better in the inoculation group, with Weissella and Lactobacillus being the dominant bacteria at different fermentation stages. Furthermore, Enterobacter aerogenes and Citrobacter freundi were identified as the main bacteria capable of producing histamine.