Gas-Producing Bacteria Causing Package Swelling in Hubei Broad Bean Paste: Isolation, Identification, and Control.

Area of Science:

• Food Microbiology
• Fermentation Science
• Food Preservation

Background:

• Swollen canned Hubei broad bean paste results in significant economic losses.
• Gas-producing bacteria are responsible for the spoilage of this traditional fermented food.

Purpose of the Study:

• To identify the gas-producing bacterium causing Hubei broad bean paste spoilage.
• To develop an effective control strategy against this bacterium.

Main Methods:

• Isolation and identification of the causative bacterium using 16S rDNA sequencing.
• Physiological characterization of the isolate (pH, temperature, salt tolerance).
• In vitro evaluation of antimicrobial agents (nisin, ε-polylysine hydrochloride, sodium diacetate) and their optimized combination.

Main Results:

• Clostridium tyrobutyricum strain LG12 was identified as the dominant gas-producing bacterium.
• The isolate demonstrated optimal growth at pH 5-7, high heat tolerance (survived 100°C for 20 min), and salt tolerance (up to 10% NaCl).
• An optimized combination of nisin (50 mg/L), ε-polylysine hydrochloride (500 mg/L), and sodium diacetate (1250 mg/L) inhibited bacterial growth by over 99%.

Conclusions:

• The study identified Clostridium tyrobutyricum from fermented chili as the cause of Hubei broad bean paste spoilage.
• An optimized antimicrobial combination effectively prevented bacterial growth and package swelling in the food system.
• This strategy offers a practical solution for preventing spoilage and economic loss in the Hubei broad bean paste industry.