Causative Microorganisms on Swelling Incident of Gochujang

Gochujang is a typical fermented food of Korea, and similar as Japanese Miso in manufacturing process. Recent favorite of consumers is preservative additive-free gochujang, and this sometimes has brought swelling incidents. The previous studies reported that salt tolerant yeast or lactic acid bacteria caused the incidents. This study sought out acid and salt tolerant and gas-generating microorganisms from an incident product of gochujang through some kinds of microbiological tests, whereas they could not reveal any salt tolerant yeast nor lactic acid bacteria. DNA sequence data of 16S rRNA gene concluded acid and salt tolerant and gas-generating microorganisms isolated should be two species of Bacillus or their relatives: one was Bacillus amyloliquefaciens and another was B. licheniformis . The former generated ca.70 ％ more gas than the later in intentional contamination of fresh gochujang. This could infer that the gas-generating Bacillus strains, B. amyloliquefaciens and/or B. licheniformis relatives might be the causative microorganisms of swelling incident of gochujang.