The microbial flora of fresh meat stored aerobically at 5 degrees C up to spoilage was enumerated and collected in order to have mixed spoilage bacterial groups to be used in competition tests against Brochothrix thermosphacta. The bacterial groups collected as bulk colonies were identified by PCR-DGGE followed by partial 16S rDNA sequencing. The predominant bacteria associated with the spoilage of the refrigerated beef were B. thermosphacta, Pseudomonas spp, Enterobacteriaceae and lactic acid bacteria (LAB). The interactions between B. thermosphacta and the other spoilage microbial groups were studied in vitro at 5 degrees C. The results showed that a decrease of the growth of B. thermosphacta was evidenced in presence of LAB at 5 degrees C while the bacterium is the dominant organism when inoculated with mixtures of Pseudomonas spp., LAB and Enterobacteriaceae. A better understanding of bacterial meat spoilage interactions may lead to improved quality of fresh meat stored in refrigerated conditions.