The Heat Disinfection of Streptococcus Faecalis and Streptococcus Lactis

SUMMARY: The heat resistance of a number of strains of Streptococcus lactis and Str. faecalis at 60° in Ringer's solution and separated milk has been determined and the Decimal Reduction Times (D.R.T.) calculated. Heating in separated milk at 60° enabled Str. lactis to be sharply differentiated in most cases from Str. faecalis. The latter gave D.R.T. values usually much above 3 min. while the former gave values usually under 1 min. and certainly less than 3 min. Single tests might give misleading results with certain strains. The log. survivor‐time graphs of both species were not always straight lines over all their length. A preliminary period of slow death was frequently observed.