S. In all, 4379 isolates from 35 products, including 24 artisanal cheeses, were surveyed with a view to identifying strains that could be used as starters in commercial dairy fermentations. Of the isolates, 38 % were classified as Lactococcus, 17 % as Enterococcus, 14% as Streptococcus thermophilus, 12 % as mesophilic Lactobacillus, 10% as Leuconostoc and 9 % as thermophilic Lactobacillus. Acid production by the isolates varied considerably. Of the 1582 isolates of Lactococcus and 482 isolates of mesophilic Lactobacillus tested, only 8 and 2 % respectively produced sufficient acid to lower the pH of milk to 5n3 in 6 h at 30 mC. In contrast, 53, 32 and 13 % of Str. thermophilus, thermophilic Lactobacillus and Enterococcus isolates respectively reduced the pH to 5n3. These isolates were found only in some French, Italian and Greek cheeses. Bacteriocins were produced by 11 % of the 2257 isolates tested and 26 of them produced broad-spectrum bacteriocins which inhibited at least eight of the ten target strains used, which included lactic acid bacteria, clostridia and Listeria innocua. The most proteolytic of the 2469 isolates tested wereStr. thermophilus from Fontina cheese followed by Enterococcus from Fiore Sardo and Toma cheese and thermophilic Lactobacillus from all sources. Exopolysaccharides were produced by 5n3 % of the 2224 isolates tested.In many Southern European countries cheeses are made from cows', goats', ewes'

The effect of a diet supplemented with yogurt containing live lactobacilli (LAB) - Lactobacillus bulgaricus and Streptococcus thermophilus - on the response of inbred mice to infection with Salmonella typhimurium was elaborated. The results of our experiments were consistent with the hypothesis that modifications of the microflora influence the adherence of S. typhimurium to intestinal mucosa, the natural antibacterial activity of the Peyer's patches lymphocytes, the accumulation of the macrophages in the liver, the proliferative responses of the splenocytes. The relationship between modifications of the immune response following ingestion of yogurt with live LAB and increased defense mechanisms was confirmed by the bacterial counts in livers and spleens and by the reduced mortality to S. typhimurium infection.

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Étude sur la microflore intestinale et sur les transformations biliaires chez des alimentées avec du yaourt (1) .

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