Antimicrobial activity of novel Lactococcus lactis strains against Salmonella Typhimurium DT12, Escherichia coli O157:H7 VT− and Klebsiella pneumoniae in raw and pasteurised camel milk

Abstract

Bad hygiene and lack of cooling facilities have resulted in spontaneously fermented African camel milk with high incidence of contaminants. Starter cultures promote food safety through fermentation control. Commercial cultures developed for bovine milk acidify poorly in camel milk and cultures optimised for camel milk with inhibitory effects against pathogens are therefore needed. Inhibition of multiple food related pathogens in raw and pasteurised camel milk during fermentation with four novel Lactococcus lactis strains was investigated. All pathogens alone in camel milk reached 8.0 log cfu mL−1. When the pathogens were cultivated with L. lactis MS22333 or MS22337 they were reduced between 0.9 and 6.0 log cfu mL−1. L. lactis MS22314 and MS22336 showed no antimicrobial activity. To our knowledge, we have for the first time demonstrated that some L. lactis strains isolated from camel milk can inhibit the growth of food related pathogens in both raw and pasteurised camel milk.