Genetic characterization of spoilage pseudomonads isolated from retail-displayed beef

This study genetically characterized Pseudomonas isolated from beef using the random amplification of polymorphic DNA (RAPD) method and correlate predominant genotypes with spoilage changes.

Pseudomonads were recovered from beef loins and steaks on days 0, 2, 4, 6, 8 and 10. A total of 309 pseudomonads were grouped into 50 RAPD types (>85% similarity). One major RAPD type contained 45% of the isolates comprising 71%, 45%, 31%, 35%, 50% and 37% of isolates from days 0, 2, 4, 6, 8 and 10, respectively, from steaks and 48% of the isolates recovered from beef loins. Nineteen RAPD types consisted of isolates that were shared between more than two sampling times, whereas the remaining 31 types were unique to one particular time.

A genetically diverse Pseudomonas population was present on the loins and steaks at each sampling time. Although pseudomonads associated with beef loins were transferred to the steaks prepared from it, a genetically diverse Pseudomonas population emerged during the retail display.

Information about the heterogeneous nature of Pseudomonas recovered from meat would help understanding the spoilage owing to predominant strains. The meat industry can use the knowledge to develop control strategies for prevalent spoilage strains.