Summary. The recovery of Pseudomonas aeruginosa, Escherichia coli, and Streptococcus faecalis from aqueous suspending media has been studied with a rich plating medium (trypticase‐soy agar) and selective media. Tap water was highly toxic to all strains investigated. Recovery of Ps. aeruginosa was most successful when phosphate buffer was the diluent. Phosphate buffer did not improve the recovery of E. coli. Streptococcus faecalis remained viable when suspended in double distilled water, deionized distilled water or phosphate buffer. Following a lag period all strains grew in 0.1% peptone water or stream water. Injury preventing recovery of viable cells on selective media occurred during suspension in all aqueous media tested, including those which supported growth. These observations suggest difficulties inherent in the interpretation of bacteriological results obtained during surveys of water sources and a need to reduce the selectivity of recovery media against injured cells.

A procedure has been developed for the enumeration of salmonellae in polluted waters using several modifications of existing techniques. Confirmation of salmonellae is achieved within 48 hr. This procedure includes selective enrichment in m-Tetrathionate Broth (22 + 1 hr), plating on Brilliant Green Sulfa Agar (20 + 1 hr), and confirmation by flagellar (H) agglutination of the growth in a mannosecontaining medium (6 i 1 hr). An incubation temperature of 41.5 C was used throughout this procedure. Dilution to extinction techniques (most probable number) were employed to enumerate salmonellae. Large sample volumes were concentrated through the use of membrane filters. This technique proved to be rapid and reliable for the enumeration of salmonellae in water, waste water, and wastewater sludges.

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A procedure has been developed for the enumeration of salmonellae in polluted waters using several modifications of existing techniques. Confirmation of salmonellae is achieved within 48 hr. This procedure includes selective enrichment in m-Tetrathionate Broth (22 ± 1 hr), plating on Brilliant Green Sulfa Agar (20 ± 1 hr), and confirmation by flagellar (H) agglutination of the growth in a mannosecontaining medium (6 ± 1 hr). An incubation temperature of 41.5 C was used throughout this procedure. Dilution to extinction techniques (most probable number) were employed to enumerate salmonellae. Large sample volumes were concentrated through the use of membrane filters. This technique proved to be rapid and reliable for the enumeration of salmonellae in water, waste water, and waste-water sludges.