Incidence of Moraxella and other gram-negative,oxidase-positive bacteria in fresh and spoiled ground beef

A total of 1535 bacterial isolates were examined from 29 retail samples of ground beef when fresh and after aerobic spoilage at 5–7°C. Of these, 1354 (88%) were gram-negative and oxidase-positive, but only 34 were identified by API 20E as Moraxella-26 from fresh and eight from spoiled samples. Ninety-five percent of the oxidase-positive isolates were Pseudomonas spp. and 66% of these were recovered from the meats after spoilage. The findings bring into question the widely-held view that moraxellae along with Acinetobacter are rather abundant in ground beef.