Molecular and technological characterization of coagulase negative staphylococci involved in the ripening of naturally fermented llama meat sausages from Northwestern Argentina.

Llama meat fermented sausages are traditional products consumed in the Andean region of South America. During sausage fermentation, lactic acid bacteria (LAB) and coagulase negative staphylococci (CNS) play an important role in meat preservation and fermentation processes and for this reason are the most microorganisms used as starter cultures in meat fermentation. The aim of the present study was to identify at species level and characterize for technological and safety characteristics, CNS isolated from fermented llama sausage (without addition of starter cultures), produced in a pilot-plant (P) and on artisanal (A) scale, to select potential starter cultures. A total of 140 colonies were isolated from Baird Parker medium, but only 55 isolates were genetically ascribed to Staphylococcus genera belonging to 6 Staphylococcus species: Staphylococcus equorum and Staphylococcus saprophyticus were the predominant followed by Staphylococcus capitis, Staphylococcus pasteuri and Staphylococcus xylosus and Staphylococcus warneri. Both productions exhibited a high variability in RAPD fingerprints: 14 and 15 strains were clustered in P and A production respectively. The CNS strains were studied to determine technological properties (nitrate reductase, proteolytic and lipolytic activities; and the ability to grow at the temperature and pH values of fermenting sausage, and at high NaCl concentrations) and safety characteristics (amino acid decarboxylase, enterotoxigenic activities and antibiotic susceptibility) by traditional methods and molecular approach. We evaluated the minimum inhibition concentrations (MIC) for eight antibiotics: ampicillin, ofloxacin, oxacyllin, kanamycin, erythromycin, tetracycline, cephaloridine and vancomycin antimicrobial. The MIC results showed high resistance for the first three antibiotics and susceptibility for the last two. Nitrate reductase activity was observed in 87% of S. equorum, whereas was absent in all S. saprophyticus and S. warneri strains. The data will be presented and discussed.