Purpose: The aim of the present study was to determine the genotypic diversity of Br. thermosphacta at strain level that developed during storage of minced pork under different conditions.
Methods: Minced pork was stored at 0, 5, 10 and 15°C, aerobically and under modified atmospheres packaging (MAP). Thus, a total of 294 Brochothrix isolates were recovered from initial, middle and final time points of storage of minced pork samples. The Brochothrix heterogeneity at strain level was performed with pulsed field gel electrophoresis (PFGE).
Results: This organism dominated at all temperatures under MAP conditions. Macrorestriction analysis of DNA of 294 Brochothrix isolates revealed a high diversity depending mostly on temperature, while the obtain fingerprints were divided in 4 different groups. More specifically, the first group consisted of the isolates from 0°C of air package and isolates from fresh meat from the batch used for packaging under aerobic conditions, the second group consisted of 4 strains, 3 isolates of final stage of 10°C, and one isolate of fresh meat. The third group consisted of isolates recovered from middle and final time point of MAP samples stored at 0°C, one isolate of air packaging at 0°C and three isolates of fresh meat from the batch used for MAP. Finally, the last group consisted of the remaining strains. Representative isolates from each group were subjected to 16S rRNA gene sequencing and assigned to Br.thermosphacta.
Significance: These observations are of great importance and are fundamental in widening the knowledge of meat microbial ecology and specifically spoilage-related bacteria and consequently understanding the meat spoilage process.