THE INFLUENCE OF TIME AND TEMPERATURE OF PLATE INCUBATION UPON BACTERIAL COUNTS OF MARKET MILK AND RELATED PRODUCTS, PARTICULARLY AFTER HOLDING UNDER REFRIGERATION1

Abstract

Use of incubation periods shorter than 3 days at 25° C, 4 days at 21° C, 7 days at 15 or 10° C and 10 days at 5° C resulted in some decrease in counts on certain samples. Incubation at 25° C for 3 days detected many samples containing large numbers of bacteria which would not develop colonies at 35° C. Negative coliform counts were obtained on many samples giving high psychrophilic counts.