Characterisation of Lactobacillus plantarum of Dairy-Product Origin for Probiotic Chevre Cheese Production

Probiotics are increasingly used as functional food ingredients. The objectives of this study were to isolate and characterise probiotic bacteria from dairy and fermented foods and to use a selected strain for the production of probiotic chevre cheese. Tolerance to acid (pH 2.0) and bile salt (0.4% (w/v)) were first investigated, and then other probiotic properties were determined. Out of 241 isolates, 35 showed high tolerance to acid and bile salt, and 6 were chosen for further characterisation. They were Lactobacillus plantarum and L. fermentum, and possessed antibacterial activities against foodborne pathogens such as Bacillus cereus, Staphylococcus aureus, Salmonella enterica and Escherichia coli O157:H7. L. plantarum (isolate AD73) showed the highest percentage of adhesion (81.74 +/- 0.16%) and was nontoxic to Caco-2 cells at a concentration of 10(8) CFU/mL. This isolate was therefore selected for the production of probiotic chevre cheese from goat's milk and was prepared in a lyophilised form with a concentration of probiotic culture of 8.6 log CFU/g. The cheese had a shelf life of 8 days. On the expiry date, the probiotic, the starter and the yeast contents were 7.56 +/- 0.05, 7.81 +/- 0.03 and 5.64 log CFU/g, respectively. The level of the probiotics in this chevre cheese was still sufficiently high to warrant its being a probiotic cheese.