Probiotic effects of lactic acid bacteria and its use as bio-preservative for tomato juice and paste

Abstract

This research focused on the use of LAB isolated from fermented cereals as bio-preservative in extending the shelf life of Tomatoes. Twenty lactic acid bacteria were isolated from fermented cereal gruel ogi, were identified as L. plantarum, L. brevis, L. fermentum, L. bulgaricus and L. pentosus. L. plantarum showed increased production and activity of Lactic acid, Diacetyl and Hydrogen peroxide over a period of five days after which there was a significant reduction. Lactic cultures were used singly and in combination for bio-preservation after samples were pasteurized at 85°C for 15 min. LAB count increased significantly from 3.2x10 to 8.3x10 cfu/g during fermentation with lactic cultures monitored over a period of 7 days at room temperature. Total yeast, coliform and aerobic plate counts between days 3-5 were 2.5x10, 2.3x10 and 3x10 cfu/g, respectively. The LAB count decreased whereas others increased significantly between days 5-7. LAB demonstrated antagonistic activity against food borne pathogens suggesting it could be a good bio-preservative by contributing to enhanced shelf life and microbial safety of foods.