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The aim of this study is to assess selective plating methodologies for the enumeration and identification of Streptococcus thermophilus, Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus acidophilus, Lactobacillus rhamnosus and Bifidobacterium animalis ssp.lactis in fermented milks. Seven agar media (MRS with added sorbitol, clindamycin or vancomycin, acidified MRS, RCA with added aniline blue and dicloxacilin, M17 and ST) were evaluated. The results showed that RCA dicloxacilin agar is suitable for the selective enumeration of B. animalis ssp. lactis in fermented milk. Either MRS (acidified) or M17 agar could be used for enumeration of L. delbrueckii ssp. bulgaricus and S. thermophilus,respectively. MRS media containing antibiotics were effective for the enumeration of the probiotic organisms (L. rhamnosus and L. acidophilus) inoculated in fermented milks. Key words: Selective media, probiotic, starter cultures, fermented milk.

Vegetal oil emulsion and passion fruit peel powder were concomitantly incorporated to milk aiming to produce new functional yogurt with health benefits. Four milk bases with similar energetic content and macronutrient composition, enriched or not with vegetal oil emulsion and/or passion fruit peel powder, were fermented with Streptococcus thermophilus , Lactobacillus delbrueckii subsp. bulgaricus and Bifidobacterium lactis ( Bifidobacterium species 420) to supply yogurts with similar appearance, flavor, and stability. Milk without supplementation was used as control. Applying hedonic scale and projective map approaches, respectively, 227 and 25 panelists analyzed the samples concerning flavor, texture-in-spoon, creaminess-in-mouth, and global impression. Instrumental firmness was also investigated. Considering the same fermentation temperature, the addition of vegetal-oil emulsion and passion fruit peel-powder did not influence fermentation time, but significantly affected instrumental firmness. Despite the observed differences in flavor and global impression there were no significant changes in consumers' overall liking between supplemented and conventional yogurts.

Development of dairy products containing bifido bacteria is one of the main focuses in the food industry, considering the health benefits attributed to its survival through gut intestinal tract and the liberation of biogenic compounds. In order to evaluate the effect of process conditions on survival of Bifidobacterium animalis subsp. Lactis HN019 and release of biogenic compounds during cold storage two technological processes were employed: (i) addition of Probiotic (unfermented bifido milk; UFBM) and (ii) fermentation (fermented bifido milk; FBM). B. Lactis HN019 counts were stable only in fermented milks during seven weeks of cold storage. Moreover, dairy matrices associated with cold storage appeared to protect bifidobacteria during exposition to gastric conditions, assuring the correct Probiotic counts at gut entrance. The distribution of fatty acids was affected by the different Probiotic products. In contrast, fermentation process increased the relative contents of some bioactive fatty acids, such as elaidic acid (+11%) and conjugated linoleic acids (+20%). It was also noted an increase in polyunsaturated fatty acids in the FBM and a higher relative content of monounsaturated fatty acids in the UFBM, as compared to control milk. In addition, fermentation process by bifido bacteria enhanced the long chain fatty acids fraction in bifido milks as compared to control and unfermented bifido milks. Control milk and unfermented bifido milk showed the same peptides even after seven days of storage in contrast with fermented milks that had increase bioactive peptides. It is possible to suggest that opioid peptides are formed during fermentation process, increasing the source of bioactive peptides. Finally, the cold conservation process modified peptides and could improve antibacterial activity.