SUMMARY:From various chilled meats, twenty‐eight strains of coli‐aerogenes bacteria and oneAeromonaswere isolated which grew well at +1±5° and some at −1±5°. The optimum growth temperature for most of these strains was nearer 37° than 30°. Nine strains (including theAeromonas) fermented lactose rapidly, the remainder slowly or not at all. All the strains which fermented lactose rapidly with the production of gas gave positive presumptive coli‐aerogenes tests in MacConkey's broth at 30°, but only five were positive at 37°; none was positive at 44°. Because such organisms can attain populations of millions/cm2, they could confuse the interpretation of presumptive coli‐aerogenes tests ma