Types of Hemolytic Streptococci in Certified Milk

In a paper by Brown, Frost and Shaw1 it was shown that the available cultures from various epidemics of septic sore throat, eleven in all, were identical as determined by certain cultural tests. For this species, or variety, the name Streptococcus epidemicus Davis was used. It was also shown that the hemolytic streptococci ordinarily found in certified milk were quite distinct from this organism. These milk streptococci were regarded as of bovine origin, harmless for man and easily distinguishable by cultural characteristics from Streptococcus epidemicus. A routine method was suggested for the examination of milk, with the idea that by its use cows infected with Streptococcus epidemicus, if such should exist, could be recognized and removed from the herd before they could become a menace to the milk consumers. The present paper deals with this routine method somewhat more in detail and gives the results obtained by its use on 1,304 group samples of milk and extending over the period of a year and a half.