Evaluation of the factors affecting the activity of sakacin C2 against E. coli in milk

Sakacin C2 is a novel, broad spectrum bacteriocin secreted by Lactobacillus sake C2 isolated from Chinese traditional fermented cabbage. Effects of milk fat, emulsifiers, preservatives and homogenization on the activity of sakacin C2 against Escherichia coli ATCC 25922 in milk were evaluated by determined the changes of viable cell counts of E. coli ATCC 25922 after inoculation (105 CFU/ml) then storage at 4 °C. Milk fat in pasteurized and homogenized milk products (low fat milk and whole milk) decreased the activity of sakacin C2 against E. coli ATCC 25922. Addition of 5 μl/ml of Tween 80 decreased the effect of sakacin C2 against E. coli ATCC 25922, but 5 mg/ml of lecithin increased the effect against E. coli ATCC 25922 in pasteurized and homogenized whole milk. Nisin and ε-Polylysine significantly increased the effect of sakacin C2 against E. coli ATCC 25922 in pasteurized and homogenized whole milk. Homogenization interfered with the activity of sakacin C2 against E. coli ATCC 25922 in pasteurized skim milk and whole milk. This study might lay the groundwork for the application of sakacin C2 as bio-preservative in milk and dairy products.