Inhibitory effect of bacteriocin - producing lactic acid bacteria against histamine - producing bacteria isolated from fish

The objective of this present work was to identify the histamine - producing bacteria isolated from fish samples collected from Chidambaram market. The bacteriocin - producing lactic acid bacteria (LAB) isolated from sea water from Vellar estuary was evaluated for the antimicrobial effects of the crude bacteriocin on the growth and histamine accumulation of histamine - producing bacteria. In the present study ten histamine producing bacteria were isolated and identified as Proteus morganii (2), Klebsiella Pneumoniae (3), Citrobacter freundii (2), Enterobacter aerogens (2) and Escherichia coli (1), Among the ten histamine producing bacterial strains, three histamine producing bacteria such as Proteus morganii (H1), Klebsiella pneumonia (H2) and Enterobacter aerogens (H3) produce hdc A gene (370bp) which is responsible for histamine production. The four lactic acid bacterial strains were identified as Lactobacillus casei (L1), Lactobacillus brevis (L2), Lactobacillus fermentum (L3) and Lactobacillus plantarum (L4) found to produce an antibacterial compound with inhibitory activity against the tested histamine - producing bacteria. The crude bacteriocin of Lactobacillus fermentum(L3) observed highest inhibition against the growth of Proteus morganii (12.5mm). The crude bacteriocin of Lactobacillus casei (L1) showed lowest activity (4.5mm) against Enterobacter aerogens. These antimicrobials therefore play a role in inhibiting the production of histamine in fermented fish products and in preventing seafood-related foodborne disease caused by histamine producing bacteria.