Isolation of Hafnia Species from Kimchi

Abstract

Eight commercially packaged kimchi products were examined over 15 days of storage at 4 degrees to evaluate the occurrence of Hafnia alvei (H. alvei). Additionally, 7 saeujeot products, as a possible ingredient source, were analyzed to examine the bacteria's origin. Over the storage period, kimchi samples had decreasing pH levels, which stabilized at pH 4.2; acidity increased to 0.9+/-0.1%. Lactose-nonfermenting bacteria, which H. alvei belongs to, gradually reduced in numbers over the kimchi storage. However, the relative frequency of H. alvei to lactose-nonfermenting bacteria tended to increase. From the kimchi samples, 58 H. alvei-presumptive colonies were selected. Forty-three colonies turned out to be H. alvei and 15 colonies were identified as other strains or of uncertain identification when the API 20E system was used. From further test, 3 of the 43 colonies were H. alvei (-) against the phage test. Finally, H. alvei was isolated from saeujeot, indicating that this ingredient can be an originating source of H. alvei in kimchi.