Development of the aerobic spoilage flora of chilled rabbit meat

Abstract

Even though worldwide production of rabbit meat is over 1,000,000 ton, little information is available on rabbit meat microbiology. This paper reports on the microflora developing on chill-stored rabbit carcasses. Four different lots of 24 h post-mortem rabbit carcasses dressed and kept at 0 °C in a medium-size abattoir were collected and evaluated for sensory, physicochemical and microbiological changes during aerobic storage at 3 ± 1 °C. Mean initial pH value (pH 24), extract-release volume (ERV) and lactate content of Biceps femoris muscle, were 6.26 ± 0.20, 13.50 ± 3.50 ml and 0.70 ± 0.07%, respectively. As with other muscle foods kept chilled in air, pH increased and ERV and lactate decreased as storage progressed. Initial levels (log cfu/g) of aerobes (APC), psychrotrophic flora, Pseudomonas spp., Brochothrix thermosphacta, lactic acid bacteria, Enterobacteriaceae and yeasts were 4.76 ± 0.31, 4.81 ± 0.81, 3.39 ± 1.12, 2.01 ± 0.92, 2.76 ± 0.51, 0.49 ± 0.45 and 3.46 ± 0.32, respectively. Pseudomonads, most of them fluorescent, and to a lesser extent B. thermosphacta and yeasts grew faster than the remaining microorganisms and became predominant at the end of the shelf life. Carcasses spoiled when mean APC, psychrotrophic and pseudomonads numbers were ca. 8 log cfu/g, their mean shelf life being estimated at 6.8 days. A lot of DFD-like rabbit carcasses, with higher pH and lower ERV values but similar microbial loads to normal meat, developed a strong putrid odour after 4 days.