Goats' milk fermented with L. rhamnosus CRL1505 could be manufactured as an alternative probiotic dairy product since this new food has the ability to stimulate the common mucosal immune system and to improve defenses against respiratory and intestinal infections.

Lactobacillus rhamnosus CRL1505 (Lr1505) stimulates immune responses in the gut and in the respiratory tract and improves resistance against Salmonella typhimurium and Streptococcus pneumoniae infections in immunocompetent and immunocompromised mice. Considering that respiratory infectious diseases continue to be a major cause of death among preschool children in developing countries, the aim of the present study was to evaluate the effect of Lr1505 on the health of children. A randomized-controlled double-blind clinical trial in 298 healthy children (2-5 years old), attending daycare centers was performed. Yogurt containing Lr1505 was administered to children for 6 months (five times a week). Results were statistically compared with those of children from the same community that received a placebo yogurt (without probiotic). Administration of Lr1505 to young children reduced the incidence of infections: 66% of children in the placebo group presented symptoms of infection while only 34% of cases were detected in the Lr1505 group. Significant differences (P<0.05) were detected in the incidence of intestinal infections, upper respiratory tract infections and angina when placebo and Lr1505 groups were compared. Children fed Lr1505 experienced fewer fevers and needed fewer antibiotics than those receiving the placebo. The protective effect of Lr1505 was associated with increased levels of mucosal IgA antibodies. Lr1505 is a promising resource for the development of prevention strategies against mucosal infections that could be effective tools for medical application. This new probiotic strain has been included into official Nutritional Programs in Argentina and it is given to more than 200 thousand children. This project has encouraged local milk production, thanks to the constant demand of probiotic yogurt containing L. rhamnosus CRL1505 by provincial governments, while incorporating innovation to small and medium enterprises.

A total of 286 lactic acid bacteria isolated from goat's dairy products in northwest of Argentina were characterized. Lactobacilli (38%) and cocci (62%) were identified according to morphological, physiological, and relevant technological properties. L. plantarum (14%) and Enterococcus (34%) were the predominant species. S. thermophilus, Pediococcus and L. plantarum were the highest acid producers. Eight strains of L. fermentum produced bacteriocins or metabolites similar to bacteriocins. The API-ZYM test was applied to 39 isolates. Eight strains were selected from their both technological properties and enzymatic activities for use as starter or adjunct culture in the manufacture of artisanal goat cheeses.

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