Authors: Donaghy JA, Totton NL, Rowe MT

Institution: Agriculture, Food and Environmental Science Division (Food Microbiology Branch), 1Dept. of Agriculture and Rural Development for N. Ireland; 2Dept. of Food Science, Queens University Belfast, Newforge Lane, Belfast, BT9 5PX, N. Ireland, United Kingdom

Summary: Dairy products such as cheese and yogurt are manufactured from pasteurised milk while in some cases sub-pasteurisation temperatures are employed for the former. Recent studies have shown increased survival of Mycobacterium avium subsp. paratuberculosis (Map) under such conditions. Therefore, the inactivation of this bacterium may rely on the manufacturing process or the product's intrinsic properties. Lactic acid bacteria (LAB) are known for their potential as inhibitors of food pathogens, a property exploited in their commercialisation as 'probiotic' products…

Map growth was inhibited (delayed) when supplemented with supernatants from a number of Lb. paracasei isolates. When co-inoculated with probiotic strains in sterile milk for 48 h (pH < 4.5) Map could not be detected by radiometric culture up to 50 days.The results of this study suggest the in vitro inhibitory effect of some lactobacilli on Map growth may be due to factors other than acid production. Irrespective of the mechanism of inhibition, the possibility exists for the inclusion of such strains in dairy products for the in situ inhibition of Map or furthermore their use as biotherapeutic agents in the gastro-intestinal tract.

Study link: http://www.paratuberculosis.org/proc8/abst4_p98.htm