β-Galactosidase for Distinguishing between Citrobacter and Salmonella

摘要: Detection of β-galactosidase with the aid o-nitrophenyl-β-d-galactopyranoside (ONPG) was examined as a means for distinguishing between Citrobacter and Salmonella. Several factors which influence sensitivity reliability test were studied. A bacteriostat, sodium azide, included to permit prolonged incubation weak negative strains enteric bacilli. By procedure described, salmonellae gave ONPG tests; all 171 positive tests.