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

Abstract
Summary: Samples 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.