Prevalence of bacteriocin-producing Lactobacillus, food spoilage, and bovine mastitis-causing bacteria in commercial foodstuffs

Introduction: Present research investigation was focused for the prevalence of bacteriocin-producing, food spoilage, and bovine mastitis causing bacteria in commercial foodstuff. Materials and Methods: A total of 389 commercial food samples comprising meat, fish products, milk and dairy products, raw vegetables and products, bakery products, beverage, and fermented rice products were investigated from various randomly selected local retail shops and supermarkets of Salem, Erode, Tirupur, Namakkal, and Coimbatore districts of Tamil Nadu. All the food samples were serially diluted and aseptically inoculated on various enrichment broth and selective media and incubated aerobically and anaerobically. Streaking and re-streaking were performed on various selective agar media until pure bacterial cultures developed. All the bacteria were subjected for various morphological and biochemical tests useful for identification up to genus and species level. Results: Microbiological investigation confirmed the occurrences of 688 bacteria comprising of Escherichia coli (86, 22.1%), Listeria (82, 21.1%), Aeromonas sp. (72, 18.5%), Clostridium sp. (70, 17.9%), Staphylococcus sp. (64, 16.5%), Lactobacillus sp. (62, 15.9%), Streptococcus sp. (54, 13.9%), Bacillus sp. (53, 13.6%), Enterobacter sp. (43, 11.1%), Salmonella enterica (39, 10%), Klebsiella sp. (33, 8.5%), and Enterococcus sp. (30, 7.7%) from various commercial food products. The Lactobacillus sp. isolated were showing antagonistic activity against the tested indicator organisms. Conclusion: Bacteriocin isolated from some Lactobacillus sp. showed good antibacterial property against food spoilage and bovine mastitis-causing bacteria and can further be studied for its applications and mode of action. The prevalence of other Gram-negative and Gram-positive bacteria from the commercial food samples is an impending danger for transfer of foodborne infections to human and animals