Evaluation of functional aspects in Lactobacillus strains isolated from dry fermented sausages

The aim of this study was to characterize lactobacilli isolated from a traditional Italian dry-fermented sausages inoculated with Lactobacillus casei/paracasei for use as probiotics. Strains isolated were L. casei (38%), L. paracasei paracasei (32%), Lactobacillus rhamnosus (21%) and Lactobacillus sakei sakei (9%). L. paracasei paracasei and L. rhamnosus showed no significant decrease in viability compared with L. casei and L. sakei sakei in artificial gastric juice; L. casei and L. sakei sakei were not affected by artificial intestinal fluid. In human embryonic intestine cell line (INT407) in vitro model, L. rhamnosus and L. sakei sakei were more adhesive than the other strains. The production of acetic acid (40.92 ± 1.94 mmol/L) and propionic acid (0.14 ± 0.07 mmol/L) was similar in all strains tested. Considerably higher (100-250 mmol/L) levels of lactic acid were produced by L. casei, L. paracasei paracasei and L. rhamnosus, and were varied depending on microaerobic or anaerobic conditions. L. casei and L. rhamnosus had the best antibacterial activity against Escherichia coli and Salmonella enterica ssp. enterica (serovar Typhimurium). These findings suggest that L. casei and L. rhamnosus merit further investigation as novel starter cultures in meat products. Probiotics are well established in dairy products but they are not widely used in meat products and it is expected their use in this area will expand considerably in the near future. Starter cultures of active or resting forms of microorganisms are widely employed in fermented meat products to improve sensory qualities. More recently they are being used in fermented meat products to improve the nutritional value of these products as functional foods. Probiotics in meat may exert their benefits by several methods, and more research is required to identify the strains and combinations of strains that produce the most health benefits. Our study demonstrates that the in vitro characterization of Lactobacillus strains directly isolated from dry fermented sausages can be useful to select novel starter cultures with potential probiotic characteristics among lactic acid bacteria used as commercial meat starter culture.