Selection of wild lactic acid bacteria for sausages: Design of a selection protocol combining statistic tools, technological and functional properties

Abstract

The main topic of this paper was the combination of statistic tools, technological, and functional properties to select starter cultures for fermented sausages. One-hundred sixty-four isolates were recovered from pork meat, and studied for their enzymatic patterns, growth as a function of temperature, pH, NaCl, nitrites and nitrates, and acidification. The growth was assessed through a spectrophotometric approach to evaluate the Growth Index; then, the data were used as input variables to run Cluster and Principal Component Analyses. Fifty-three promising isolates were selected for their Growth Index in presence of salt, nitrites, at low temperatures, or acidification. These isolates were studied for some functional properties (survival at pH 2.0/2.5, and in presence of bile salts, hydrophobicity, auto-aggregation, antibiotic resistance, antimicrobial activity towards some foodborne pathogens). The results of these experiments were used to select 4 best candidates, using the statistical distribution of each trait (median and quartiles). As a final step, the isolates were identified as Lactobacillus plantarum and studied for their ability to inhibit foodborne pathogens, a mould (Mucor spp.) or for the lacking of negative interactions with an adjunct starter of fermented sausages (Staphylococcus xylosus).