Effect of inoculation of selected Staphylococcus xylosus and Lactobacillus plantarum strains on biochemical, microbiological and textural characteristics of a Tunisian dry fermented sausage

In this study, a selected starter culture of Lactobacillus plantarum and Staphylococcus xylosus was used for the manufacture of a traditional Tunisian dry fermented sausage. Changes of microbiological, biochemical, sensorial and textural characteristics during the ripening of sausages were investigated. Counts of lactic acid bacteria and staphylococci were significantly higher in inoculated sausages than in control ones. Moreover, the acidifying activity of the selective L. plantarum strains improved the hygienic quality of fermented sausages by reducing counts of Enterobacteriaceae. Both a significant decrease in pH and a significant increase in nitrite contents were observed in inoculated sausages compared to control ones. The loss of moisture during the ripening of sausages was not affected by the use of starters. Proteolysis and lipolysis were observed both in control and in inoculated sausages; however, these activities during ripening could be due to the activity of starter culture enzymes or the activity of meat endogenous enzymes. The Factorial Discriminative Analyze (FDA) of sensorial parameters (aroma, color, taste and firmness) discriminate clearly inoculated sausages from non-inoculated ones. In fact, inoculated sausages showed a more intensive red color, related to the production of nitrosomyoglobin pigment, and an acid flavor. Finally, textural parameters of sausages were not affected by the use of the selective starters.