1998 Volume 42 Issue 3 Pages 203-209
In order to minimize the denaturation of proteins in milk, normal cow's milk was pasteurized at 61C for 20min. The protective effects of the thus prepared skim milk (low-heat skim milk) on exogenous and endogenous infection were examined as compared with conventional skim milk which was pasteurized at 121C for 2sec. The antibody titers to Listeria monocytogenes and Escherichia coli of low-heat skim milk were almost equal to that of raw milk, while no antibody was detected in the conventional skim milk. When mice were given low-heat skim milk or conventional skim milk, the incidence of the translocation of orally inoculated Listeria monocytogenes to the spleen was lower in the low-heat skim milk group than that in the conventional skim milk group. The life span of 7Gy X-ray irradiated mice given low-heat skim milk was significantly prolonged in comparison to that of mice given conventional skim milk. However, there were no differences in the number of bacteria in the feces or IgA production by Peyer's patch cells between the two groups. These results suggest that antibodies in low-heat skim milk, which still have reactivity to exogenous or indigenous bacteria, may contribute to the protective effects against bacterial infection.
