Test media for identification and differentiation of enterobacteriaceae,general coliforms, aeromonas, and salmonella

Abstract From the Canadian patent

A test medium is disclosed which enables the quantification and differentiation under ambient light of aggregates of biological entities producing specific enzymes, which may include general coliforms E. coli, Aeromonas, and Salmonella or Shigella. Nonchromogenic substrates are disclosed which produce a substantially black, non-diffusible precipitate not subject , to interference from other chromogenic substrates present in the test medium. In a prefered form, the substrates are selected such that E. coli colonies present in the test medium show as substantially black general coliforms , colonies as a blue-violet color Aeromonas colonies as a generally red-pink color, and Salmonella …