Monitoring of staphylococcal starters in two French processing plants manufacturing dry fermented sausages.

AIMS: The growth and survival of Staphylococcus xylosus and Staphylococcus carnosus were monitored during sausage manufacture in two processing plants. METHODS AND
RESULTS: The gram-positive, catalase-positive cocci isolated from the processing plants F10 and F11 were identified by Staphylococcus-specific PCR and species-specific oligonucleotide array. In the inoculated products with starter cultures, 90% of staphylococcal strains isolated in F10 were identified as S. xylosus and 10% as S. carnosus. In F11, 77% were identified as S. xylosus and 20% as S. carnosus. Staphylococcus xylosus dominated the staphylococcal microbiota while S. carnosus survived during the process. The pulse-field gel electrophoresis analysis revealed that all S. xylosus and S. carnosus strains isolated corresponded to the starter strains inoculated. The two starter strains of S. xylosus co-dominated in the isolates from sausages of F11, whereas the strain with pattern A1 was dominant in the isolates from sausages of F10. In the environments, no S. carnosus and S. xylosus were found, whereas Staphylococcus equorum and Staphylococcus saprophyticus were the main species isolated.
CONCLUSIONS: This work highlighted the domination of S. xylosus starter strains, which showed a strong capacity to grow during sausage process, while S. carnosus survived during the process. SIGNIFICANCE AND IMPACT OF THE STUDY: Successful implantation of starter cultures is obviously a prerequisite for their contribution to sensorial qualities. Thus, the monitoring of the growth and the survival of S. xylosus and S. carnosus are required to guarantee a well-adapted starter culture. This study revealed that the two Staphylococcus species are suitable for manufacturing sausages in processing plants with very different capacities of production.