The microstructure, texture and sensory properties of control (full fat) and experimental fresh Tallaga cheeses produced by replacing milk fat with Sunflower Oil (SO) and/or Whey Protein Concentrate (WPC) were investigated. Scanning electron micrographs displayed WPC cheese (total replacement of milk fat with whey protein cheese) with a compact and close network. Also, SO cheese (total replacement of milk fat with sunflower oil) showed a compact network with small uniform oil droplets embedded in the protein matrix, but full fat cheese exhibited an open protein matrix containing milk fat globules of various sizes and forms. Textural tests showed that the WPC cheese was harder, more cohesive, gummier and chewier than those of other experimental cheeses. The cheese with 50% sunflower oil and 25% whey protein concentrate was more acceptable than other experimental cheeses and showed a similar texture and structure to those of fresh full fat Tallaga cheese.

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The effect of Rayeb milk supplementation with fenugreek extract (2.5, 5.0, 7.5 and 15%) on the chemical, microbiological and sensory characteristics was studied. Results revealed that use of fenugreek extract in Rayeb milk production increased total solids, ash, fat, diacetyl and carbohydrate contents with increasing fenugreek extract levels. The viscosity of control Rayeb milk markedly increased compared with the treatments during cold storage. Microbiological results showed that the control Rayeb milk had the highest total bacterial count. The yeasts and moulds were not detected through the storage period for all fenugreek extract Rayeb milks. The sporformes were not detected in 7.5 and 15% treatments all over the storage time. The fenugreek extract Rayeb milk treatments gained the highest score either when fresh or throughout storage periods compared with the control. Scores of sensory evaluation decreased by progressing storage period. The texture of Rayeb milk with 15% fenugreek extract became softer and smoother at the end of the storage period. It could be concluded that, the (7.5%) treatment was the best one.

Sixty-nine yeast isolates were collected from different sources. The isolates were tested using agar well diffusion and disc diffusion assays against eight medically important indicators. Results indicated that 48 (69.6%) of isolates exhibited antibacterial activity against one or more of the eight indicator bacteria. When pH was adjusted to 6.5, only 26 isolates were effective. The stability of yeast isolates supernatants at pH 6.5 against proteolytic enzymes was also tested. Only sixteen isolates were effective against test microorganisms. When the supernatants were treated with catalase and trypsin, only thirteen isolates showed antibacterial activity. The isolate Eg-Y2 was very effective against Cl. tyrobutyricum which is considered as one of the most dangerous anaerobic pathogens. . The 13 isolates were identified as C. pelliculosa ,C. guillermondii, C. glabrata, C. famata, Cryptococcus neoformans, Rodo muciluginosa using the 20 CUX API system.