Isolation, identification and application lactic acid bacteria to “tom chua” in Go Vong town, Tien Giang province

Abstract

The objective of this study is to isolate, identify and examine several beneficial lactic acid bacteria in “Tom chua” – a lactic product of Go Cong town, Tien Giang province. Eighteen strains of lactic acid bacteria were isolated from four samples. Their colonies are milky white or ivory, whole or serrated, cellular, gram positive and catalase and oxydase negative. They have a high ability to produce lactic acid in broth MRS broth at concentrations of 0, 4, 6 and 8 % (1,12 – 2,19 mg/ mL in 24 hours of culture). In particular, bacteria strains GK1 and GH5 are more likely to produce lactic acid than the remaining strains in the environment at the four salt concentrations. In to harsh environments, the GK1 bacterial strain exhibits several probiotic properties such as resistance to low pH, pepsin and bile salts. These two strains were identified as L. farciminis GK1 and L. futsaii GH5 because they are 99% homologous to Lactobacillus farciminis and Lactobacillus futsaii. The addition of bacterial starter to sour shrimp fermentation helps to shorten fermentation time (37.14 % compared with the control). The sensory evaluation shows that the product is over average quality and meets microbiological criteria according to QCVN 8 - 3: 2012 / BYT.