386. Variations in morphology of Streptococcus lactis when grown in raw and heated milk

Abstract

1. Streptococcus lactis cultures were found to vary considerably in their morphological characters when grown in raw and heated milk.2. This variation in morphology was found to be the main cause for the difference in colony counts between inoculated raw milk and milk heated to 70° C. for 1 hr. over a 6 hr. incubation period at 37° C.3. Similar T.M.C.'S on inoculated raw and heated milk during incubation at 37° C. explained why the methylene-blue reduction times were the same.4. It is thought that denaturation of protein may be responsible for the production of short chains in heated milk.5. The by-products of growth of Str. lactis are responsible for the production of short chains in raw milk after a long incubation time at 37° C.