Gram-negative identification card for identification of Salmonella, Escherichia coli, and other Enterobacteriaceae isolated from foods: collaborative study.

Twelve laboratories evaluated the Gram-Negative Identification (GNI) Card to identify members of the Enterobacteriaceae. Eighty-four isolates, previously isolated from foods, were used in the collaborative study; the isolates represented 12 genera within the Enterobacteriaceae group. Each collaborator streaked each isolate on tryptic soy agar plates for purity.