Rate of Acid Production by Some Lactic Streptococci Individually and in Combination in Buffalo Whole and. Skim Milk at Different Temperatures 

Abstract

The present study was planned to examine the rate of acid production by Streptococcus lactis, Str. cremoris and Str. diacetylactis (DRC1,) singly and in combination in buffalo skim and whole milk at 25 and 30°C. The cultures were inoculated at 5%, rate (V/V) in both the types of sterilized milk and incubated at 25 and 30°C for 10 hours. For combinations cultures were grown separately and mixed before use. The mixed cultures inoculated at 5% rate in 1:1 ratio as above. Hourly samples were drawn to measure titratable acidity expressed as per cent lactic acid (% L.A.) upto 10 hrs. of incubation. The cultures when grown-singly or in combination performed -better at-30°C at than at 25°C. The acid production was higher in skim milk than in whole milk at both the temperatures, Individual cultures produce more lactic acid than mixed cultures in both the type of milk and at both the temperatures. Thus it is proved that these streptococci are non-symbiotic. Maximum acid production (1.2% L.A.) at the end of 10th hour was achieved by Str. lactis in skim milk at 30°C.