Stracchino light quale vettore di colture probiotiche

Dairy products appear to be good vehicles for the delivery of probiotics to humans. Commercial probiotic strains Lactobacillus casei, Lb. rhamnosus, Lb. plantarum, Lb. paracasei subsp. paracasei, Lb. acidophilus, Bifidobacterium lactis, B. animalis subsp. lactis were investigated for the production of a probiotic light Stracchino cheese. Strains were incorporated into Stracchino cheese as free cells as multispecies mixtures with different ratios. The viability of the probiotics was evaluated during manufacture, ripening (1 and 6 d) and storage (26 d at 4°C). Furthermore the survival of incorporated bacteria was tested simulating in vitro gastrointestinal conditions. With an additional level of 10 6 cfu/mL of milk at the end of the shelf-life the mean value of the cell count of probiotic strains was 7.4 log 10 CFU/g (ranging from 7.0 to 9.1 log 10 CFU/g). The presence of probiotic strains didn't influence the growth of Streptococcus thermophilus used as starter. Sensory and structural properties, body and texture of the Stracchino cheese with incorporated Lactobacillus acidophilus and Bifidobaterium animalis subsp. lactis were the most similar to the characteristics of Stracchino cheese produced by the conventional method. Probiotics maintained levels greater than 10 7 CFU/g which is the requirement to provide therapeutic benefits. Differently from the other tested mixtures, the employment of Bifidobacterium only and Lb. acidophilus didn't show a higher lactic acid content than the control cheese. The probiotic strains survival wasn't significantly influenced by the passage of the cheese through lysozyme, pepsine, pancreatin and bile salts: at least 7.29 log 10 CFU/g were detectable at the end of the simulation of gastrointestinal trait.