POTENTIAL ROLE OF PROTEUS-PROVIDENCIA-MORGANELLA SPECIES IN QUALITY DETERIORATION OF BEEF

Proteeae Isolation Medium of Hawkey et al. (1986) was effective for is olation and enumeration of Proteus-Providencia-Morganella spp. from be ef and beef products. On this medium colonies were brown, surrounded b y a zone of clearing. In an examination of retail beef samples package d and stored in polyvinyl chloride (PVC) film, 5% contained these bact eria in a concentration of 10(1)-10(2) cells per gram or cm2. Isolates from retail beef samples included P. vulgaris, P. alcalifaciens, P. r ettgeri, and M. morganii. None of the retail samples packaged and stor ed in high oxygen barrier (HOB) film contained detectable Proteus-Prov idencia-Morganella spp. Steaks inoculated with Proteus-Providencia-Mor ganella spp. and packaged and stored at 4-degrees-C in P VC film (15 d ays) or in HOB film (42 days) usually had a reduced count of Proteus-P rovidencia-Morganella spp. during storage. Slight increases in counts occurred on steaks inoculated with P. vulgaris and P. rettgeri and sto red at 4-degrees-C for 15 days in PVC film.