The pyruvate test for monitoring the bacteriological quality of raw silo tank milk

Abstract

SummarySamples of milk from silo tanks were stored at refrigeration temperatures and examined at intervals for pyruvate content and total colony count. Significant relationships between pyruvate, μg/ml, and log colony forming units (cfu)/ml were established for samples stored at 2°C for 2, 3 and 4 d (3, 4 and 5 d of age respectively) but at 5 and 7°C the relationships after 2-d storage (3 d of age) were not significant. From an overall relationship it was predicted that 4 μg pyruvate/ml would correspond to a bacterial content of 3·7 x 106cfu/ml with 95% confidence limits of 6·6 x 10 cfu/ml. 2·1 x 107cfu/ml.