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In this study, the Saccharomyces cerevisiae biomass was applied to remove mercury in milk which is the common dairy product and the ability of this profitable yeast in bioremoving the Hg low concentrations (ppb) in milk was investigated. The initial Hg concentration, biomass dosage, and contact time effects on removal efficiency of S. cerevisiae were studied and they were also optimized by the central composite design. The Hg biosorption data were verified before the final analysis. The results showed that the optimal condition for the bioremoval of Hg was 80 μg/L and 22 × 108 CFU in the third day for initial Hg concentration, biomass dosage, and contact time, respectively. The maximum Hg bioremoval level in optimal condition was 70%. There were no significant differences in mean scores for sensory properties of milk samples during storage (p <.05). Practical applications: Our findings indicate that Saccharomyces cerevisiae known as a potent yeast to absorb the high amounts of toxic heavy metals in milk, it can also be applied for Hg elimination from water and foodstuffs even in low concentrations. Application of yeast for cleaning of humankind environment would be killing two birds with one stone using waste of an industry for decontamination of environment and food. [ABSTRACT FROM AUTHOR]

In this study, the effect of homogenization pressures (100, 150 and 200 bar) at 50, 60 and 70C and stages (1 and 2) on viability of probiotic bacteria was investigated. The milk used for producing yoghurt samples was homogenized at 100, 150 and 200 bar at 50, 60 and 70C, then heated at 85C for 30 min. After cooling milk to fermentation temperature (42C), it was inoculated with mixture starter culture ABY-1 and incubated. During fermentation, pH dropped until it reached 4.5. After fermentation, yoghurt samples were held in refrigerator. Viability of Lactobacillus acidophilus and Bifidobacterium lactis was determined during a 21-day cold storage (4C). The results of this study showed that with increasing pressure, temperature and stages of homogenization, viability of probiotic bacteria increased during storage (P < 0.05). [ABSTRACT FROM AUTHOR]