NEW APPROACHES TO MEASURING TOTAL BACTERIAL POPULATIONS IN WATER SUPPLIES.

DIRECT COUNTS OF STAINED BACTERIAL CELLS WERE COMPARED WITHCOUNTS OBTAINED FROM STANDARD PLATING TECHNIQUES. THE METHOD USED BY THE AUTHORS COMBINED ACRIDINE ORANGE STAINING WITH2-(P-IODOPHENYL)-3-(P-NITROPHENYL)-5-PHENYL-TETRAZOLIUM CHLORIDE REDUCTION. TO OVERCOME THE INTERFERENCE OF A MEMBRANE FILTER'S PORES WITH THE IDENTIFICATION OF STAINED CELLS, A GEL-STRIPPING TECHNIQUE WAS USED TO TRANSFER THE BACTERIAL CELLS FROM MEMBRANE FILTERS TO A GELATIN MATRIX BEFORE COUNTS WERE MADE.