SEASONAL VARIATION IN CHEESE STARTER ACTIVITY

Abstract

Summary:Depression of activity of certain single strain starter cultures in H.T.S.T. pasteurized milk during the October‐April season was observed, but the effect was removed by momentary boiling. The addition of a small percentage of such milk to autoclaved milk reduced the activity of these cultures. These ‘inhibited’cultures were unable to grow in modified Niven's medium even when additional known growth factors were added. Using a whey agar medium, active ‘uninhibited’colonies may be picked and a ‘failing culture’revived.An hypothesis postulating an inhibitor‐growth factor antagonism is advanced, to explain the findings.