||Modified Agar Medium for Detecting Environmental Salmonellae by the Most-Probable-Number Method.
Hussong, D. ;
Enkiri, N. K. ;
Burge, W. D. ;
||Agricultural Research Service, Beltsville, MD. Biological Waste Management and Organic Resources Lab. ;Maryland Conservation Service, Beltsville.;Environmental Protection Agency, Cincinnati, OH. Water Engineering Research Lab.
Culture media ;
||Some EPA libraries have a fiche copy filed under the call number shown.
Salmonellae in the environment remain a potential source of disease. Low numbers of salmonellae have been detected and enumerated from environmental samples by most probable number methods that require careful colony selection from plated agar medium. A modified xylose lysine brilliant green medium was prepared to control the loss of selectivity caused by heating the brilliant green component. Added agar reduced colony spreading. The medium contained 47 g of xylose lysine agar base per liter; the agar content was adjusted to 2%, autoclaved, cooled to 50 degrees C, and then amended just before pouring to include H2S indicator and 7 ppm (7 ml of 1:1,000 brilliant green per liter) of unheated brilliant green dye. H2S-positive salmonellae were easily detected from sewage sludge compost to the exclusion of most other gram-negative bacteria.