Growth of spoilage bacteria during storage and transport of meat

Pseudomonads and lactic acid bacteria (LAB) are the most relevant organisms for assessing the effect of specific chilling time–temperature scenarios on the growth of spoilage bacteria under aerobic and anaerobic (vacuum packs) conditions, respectively. Pseudomonad growth was modelled on beef, pork and lamb carcasses, chilled to specific target surface temperatures and compared with the growth that would be achieved if the carcasses were chilled to a core temperature of 7°C (Regulation (EC) No 853/2004). Pseudomonad growth with the combination of chilling the carcass surface to a target temperature (1–10°C for beef and lamb, and 5–10°C for pork) and transportation at that temperature plus ± 1°C was also modelled for 1–48 h (assuming an initial count of 1 CFU/cm²). Finally, the growth of pseudomonads and LAB was modelled on meat intended for use in minced meat/meat preparations, stored at temperatures of 1–7°C (inclusive) for 1–12 days. The effect of storage temperature and initial count on the time to reach 10⁷ CFU/cm² was also investigated. The outputs suggest that chilling bovine or ovine carcasses to between 4 and 10°C surface temperature, inclusive, results in similar or lower predicted pseudomonad growth as compared to chilling to a core temperature of 7°C. The results for porcine carcasses depended on the target surface temperature and chilling curve applied. It was also predicted that pseudomonads and LAB grow steadily on meat stored at 1–7°C and LAB counts exceeded 10⁷ CFU/cm² when stored for 11 days at 7°C. It was concluded that the time– temperature chilling profiles that may be used to obtain similar or less growth to that obtained when chilling to a core temperature of 7°C is dependent on the initial contamination level.