File:Salmonella enterica serovar typhimurium 01.jpg

Salmonella enterica serovar Typhimurium bacteria cultured on Hektoen enteric (HE) agar medium; S. enterica Typhimurium colonies grown on HE agar do not ferment lactose, and thus appear blue-green; it does produce hydrogen sulfide, however, and there can be black-colored deposits present.

Obtained from the CDC Public Health Image Library.

Image credit: CDC (PHIL #6704), 1976.