Characterization of yeast flora isolated from blue-veined cheese

Yeast populations are frequently found in blue-veined cheese. In order to investigate yeast communities, one hundred cheese samples were collected from the Egyptian retail markets. Two hundred and forty eight yeast isolates were examined along with nine standard yeast strains using morphological and biochemical reactions. The obtained data applied to numerical analysis to compute the dendrogram. The isolated yeasts belong to eight genera and nine different species in which seven species were ascosporongenous: Debaryomyces hansenii [35.8%], Torulaspora delbrueckii [16%], Saccharomyces cerevisiae [14.8%], Kluyveromyces marxianus var lactis [5.8%], Pichia farinsa [5.4%], Yarrowia lipolytica [4.7%] and Zygosaccharomyces rouxii [3.9%] while one genus with 2species was nonascosporongenous: Candida versatilis [8.6%] and C.zeylanoides [5.1%]. Generally, Yeasts were found in high numbers, making their occurrence in blue-veined cheese meaningful

Microbial and Mycotoxic study on commercially available cinnamon in Egypt

The investigation was performed to assess the microbial profile, mycotoxin content and antibacterial activity of cinnamon in Egyptian retail. A total of 180 samples, representing loose, filter-bags and barks commercial available products were collected and examined in dry and drink form. The results indicated that, in the dry form, total viable bacteria, spore-forming viable bacteria and fungal count [molds and yeasts] as well as total aflatoxin were the highest in loose samples while the lowest were in bark group. Among the drink form, only the loose group was contaminated with low numbers, i.e, 3.4 x 10[1], 3.2 x 10[1] and 4 x 10[1] CFU/g of total viable bacteria, spore-forming bacteria and fungal count, respectively, with significant reduction [p<0.05] in comparison with the dry form. Nevertheless, no detectable levels of coliform group, Escherichia coli, Staphylococcus aureus, Bacillus cereus, Salmonella sp, Clostridium perfringins and ochratoxin A were found in any of the samples. Common pathogenic bacteria, E. coli showed sensitivity to 2%, B. cereus and staph. aureus were sensitive to 3% ethanolic extract, while no response was found against aqueous extract. Finally, good quality and preparation protocol may have the advantage to reduce microbial and mycotoxin hazards

Protein decomposition during ripening of cheese manufactured by coagulation total milk protein

The soluble milk protein was denatured by inoculating the milk with 3.6 mM calcium chloride, followed by heating to 92C for 15 seconds of which Ras Domiati and Kariesh cheeses were manufactured. Decomposition of protein was examined in the fresh cheeses as well as during ripening. By using this method, whey proteins incorporated with milk casein in the cheese, increased the total nitrogen and the total amino acid content of the product. Nitrogenous compounds, i.e., soluble nitrogen, non protein nitrogen, amino acid nitrogen, tryptophan as well as free amino acids were released in higher amounts in the experimental cheeses than those of the cheese made by the standard method when young and during ripening. Therefore, the product had a higher content of essential free amino acids

Microstructure and chemical changes in Karish cheese prepared from reconstituted ultrafiltrated milk

Retentate was prepared from reconstituted skim milk by ultrafiltration [UF] and used in Kariesh cheese making. Microstructure and protein hydrolysis in cheese were examined when fresh and after 3 and 6 weeks of ripening. UF cheese had better quality than that made from reconstituted milk by the conventional methods. Protein degradation was more evident in UF cheese resulting in more liberation of free amino acids. The free amino acids released from cheeses, not only differed in their quantitative values but also in their nature and numbers. Thirteen free amino acids appeared in young cheeses then increased to 16 during ripening. TEM and SEM micrographs showed no apparent differences in the microstructure and the fusion of protein particles in both cheese when fresh and during ripening. In Kariesh cheese the fusion of protein advanced more extensively at surface that in the interior body of cheese