BACTERIOLOGY OF MILK HELD AT FARM BULK COOLING TANK TEMPERATURES

Abstract

Raw milk samples containing less than 50,000 bacteria per ml. were compared with samples over 50,000 per ml. by means of bacterial counts mode during four days of storage at 36° F., 38° F., 38° F., with periodic raises to 45° F. or 50° F., and 45° F. More samples of the high count milks showed appreciable growth within one, two, three or four days than of the low count milks, but psychrophiles often grew faster, especially after two days, in the low count milk. Raw milks are more likely to remain Grade A for a desired storage period if they contain low numbers of bacteria and if their storage temperature is 38° F. or lower.