The Bacteriology of Farm Water Supplies: A Study of the Colony Count in 72 Hours at 22°

SUMMARY: The colony count at 22° of farm water supplies from springs and wells was mainly composed of biochemically inactive, non‐pigmented, Gram‐negative rods. Water from a stream polluted with farmyard sewage showed a similar dominance of Gram‐negative rods, but orange or yellow pigmented colonies were more abundant. There were few 37° positive coli‐aerogenes bacteria in either the farm water supplies or the sewage polluted stream, and Bact. coli type I was rare. A high proportion of the bacteria from farm water supplies fermented milk in 3 days at 22°; a third developed acid, 15% proteolysis and 6.4% ropiness. Contamination of pure spring water with surface soil from a heavily grazed pasture resulted in a hundredfold increase in colony count with aerobic sporing rods replacing Gram‐negative rods as the dominant organisms, but coli‐aerogenes bacteria were absent.