Effect of cadmium on the growth ofLactobacillus lactis, L. helveticusandStreptococcus thermophilusin milk

Abstract

SummaryThe viable counts, pH and production of lactic acid were determined forLactobacillus lactis, L. helveticusandStreptococcus thermophilusafter 0, 5 and 24 h anaerobic incubation at 44 °C in skim milk containing 0, 3, 5 or 7μg cadmium (Cd)/l. In skim milk containing 7μg Cd/l, a noticeable decrease in lactic acid production and inhibition of the decrease in pH was observed for all three strains after 24 h, although there was only a slight inhibition of growth. With 3 and 5μg Cd/l, there was only a slight inhibition in the decrease in pH. In addition, with 3 μg Cd/l some evidence of stimulation of lactic acid production was found. The inhibitory effect of low Cd concentrations on lactic acid bacteria may give rise to problems in the dairy industry.