RAPID COUNTING OF BACTERIA IN RINSES OF MILKING EQUIPMENT BY A MEMBRANE FILTRATION-EPIFLUORESCENT MICROSCOPY TECHNIQUE

Membrane filtration and epifluorescent microscopy were used for the rapid enumeration of bacteria in rinses of milking equipment. Rinse solution (10 ml) was filtered through a 0.6 .mu.m pore size Nuclepore membrane filter and the bacteria retained stained with acridine orange. The clump count of orange fluorescing bacteria on the membrane correlated well with the corresponding plate count (r = 0.83). The technique is rapid, taking approximately 10 min, and is sufficiently sensitive to detect 1000 bacteria/ml rinse (equivalent to 5 .times. 105 bacteria/m2 of milking equipment surfaces by the method currently in use).