Repressive efficacy of lactic acid bacteria against the human pathogenic and fish-borne spoilage microbiota of fresh Indian mackerel fish chunks
Different strains of lactic acid bacteria (LAB) namely Lactobacillus acidophilus NCIM 2287, Lactobacillus plantarum NCIM 2085, Lactobacillus helveticus NCIM 2126 and Lactococcus lactis NCIM 2114 were procured from the National Chemical Laboratory (NCL) Pune, India. These LAB cells were individually (107 cfu/ml) sprayed using a sterile syringe on the dressed fresh mackerel fish chunks and incubated at 37°C for two days. The growth pattern of each LAB and their antagonism against fish-borne spoilage bacteria namely, specific spoilage bacteria, halophilic bacteria, coliforms, lipolytic, proteolytic bacteria and total plate count were estimated for three days. Pathogenic Staphylococcus aureus was inhibited by Lb. acidophilus on the second day with 4.30 log difference as compared to control. The growth of specific spoilage bacteria was decreased by Lb. plantarum spray on the first day by 1.0 log difference. Lb. helveticus inhibited S. aureus on the third day by 3.5 log difference. Out of the four LABs tried, Lb. helveticus showed the best inhibitory effect against the fish-borne bacteria. All three LABs exhibited inhibition against the fish-borne spoilage bacteria, they may thus be potentially used as bio-preservative bacteria to preserve the whole fish meat or minced meat products etc. for a shorter duration.
Key words: Lactobacillus helveticus, Lactobacillus plantarum, Lactococcus lactis, Lactobacillus acidophilus, antagonism, spoilage bacteria, mackerel fish.