Gas-producing spoilage bacteria in compound seasoning sauce: Identification, characterization and its control

Compound seasoning sauce is susceptible to microbial spoilage during storage, which can lead to package swelling, thereby posing a serious threat to both product shelf life and food safety. High-throughput sequencing, traditional culture isolation, and inhibition experiments were employed to systematically investigate the gas-producing spoilage bacteria in compound seasoning sauce and its control strategies. The results demonstrated that, compared with normal sauces, the swollen bagged samples exhibited a significant increase in TCA-soluble peptide and reducing sugars content, along with a sharp decline in bacterial diversity. The Bacillus was identified as the absolutely dominant bacterial group in the swollen bagged samples. Through gas-production verification, Bacillus haynesii was determined to be the primary gas-producing spoilage bacterium. It exhibited strong salt tolerance and heat resistance, and was capable of utilizing various sugars to produce acids and gas. Microbial inhibition experiments indicated that individual applications of heat treatment (95 °C, 20 min), high salt concentration (≥13%), or nisin (0.2 mg/mL) could effectively inhibit this bacterium, but combined applications yielded superior results. The preferred control strategy was established as follows: adjusting the sauce salt concentration to 11%, adding 0.1‰ nisin, and combining with heat treatment at 95 °C for 20 min, which achieved complete inhibition of the Bacillus haynesii in compound seasoning sauce. This study identified the key spoilage bacteria causing the package swelling of compound seasoning sauce and proposed corresponding antibacterial measures, thereby providing important guidance for extending the shelf life and quality control of seasoned sauces.