SUMMARY: Aerogenes‐cloacae and Intermediate types of coli‐aerogenes bacteria were found to be normal inhabitants of ears and panicles of growing cereals. Coli‐aerogenes bacteria, producing acid and gas in MacConkey's broth within 5 days at 30°, were isolated from 73% of the 148 samples, the number being as high as 105/g in a third. The number of organisms increased during the growing season. Less than a third of the samples contained 37° positive strains, but approximately 10% were positive in 10‐3g or less at this temperature. A high proportion (71.1%) of the 180 classifiable cultures did not produce acid and gas in MacConkey's broth in 2 days at 37°. Organisms of the aerogenes‐cloacae types were dominant, constituting 80.6% of the classifiable strains at 30° and 80.8% of the 37° positive strains. Intermediate type I, particularly 37° negative and gelatin liquefying variants, was the next most common type.

Farm water supplies giving 37" positives in MacConkey's broth within 24 hr. had a much higher incidence of presumptive Bact. coli type I than those which gave 37' positives during the second day of incubation only; presumptive Bact. coli reactions were obtained with SiiO,& of the 7,522 tubes positive in 24 hr. compared with 23% for the 7,593 tubes showing positive reactions during the second day at 37".

Summary: The flaming of taps before sampling caused no significant differences in the most probable numbers of coli‐aerogenes organisms or Bact. coli in water samples, or in the colony counts at 37 or 22°, though there was a tendency for the bacterial content to be lowered.

SUMMARY: A series of 1,040 cultures of coli‐aerogenes bacteria isolated at 30° from farm dairy equipment and raw milk was classified according to the recommendations of the Coliform Sub‐Committee of the Society for Applied Bacteriology (Report, 1949). The distribution of species and types isolated from milk did not differ materially from that for dairy equipment, Klebsiella cloacae, K. aerogenes and Citrobacter freundii being the dominant species, while the incidence of Escherichia coli was relatively low. There was no marked seasonal incidence of any type, though E. coli I formed a slightly higher proportion of the coli‐aerogenes microflora in winter, whereas K. aerogenes I was slightly higher in summer. Many of the cultures of the dominant types, K. cloacae, K. aerogenes I and Cit. freundii I, did not form acid and gas from lactose in two days at 37°. Consequently 37° negative, anaerogenic and paracolon strains constituted a relatively high proporton (49%) of the coli‐aerogenes microflora.

Summary: The incidence of the main types of bacteria among 2,856 isolated on Yeastrel‐milk agar incubated at 30° from 121 rinses of dairy equipment cleansed by chemical methods, showed that micrococci were dominant in low colony count (<104/ft2) rinses of equipment treated by immersion cleaning in caustic soda or cleansed in detergent‐hypochlorite solutions, whereas nonpigmented Gram‐negative rods were dominant in low count rinses of equipment cleansed with detergent‐sterilizers containing quaternary ammonium compounds. Gram‐negative rods were dominant and streptococci frequent in high count (<2·5 × 105/ft2) rinses irrespective of the chemical used. A high proportion of the streptococci and coli‐aerogenes organisms gave acid reactions in litmus milk after 72 h at 22°, many of the anaerogenic Gram‐negative rods and several of the aerobic sporeformers gave proteolytic reactions, whereas the majority of the micrococci, corynebacteria and other asporogenous Gram‐positive rods showed no change. Bacteria isolated from high count rinses were more active in producing milk spoilage reactions at 22° than those isolated from low count rinses.