Prevalence of aerobic spore forming bacteria in raw milk, Ras cheese and Domiati cheese was investigated. Total bacterial and total aerobic spore forming counts were enumerated by using tryptone soy agar medium. All isolated aerobic sporeformers were identified on genus and species levels. The minimum, maximum and the means of total aerobic sporeformers counts in raw milk samples were 3.2×10 3 , 2.7×10 4 and 1.5×10 4 cfu/ml, respectively. Counts in Ras cheese samples were, 2×10 2 , 3.5×10 4 and 1.8×10 4 cfu/g, and in Domiati cheese samples being, 1.2×10 3 , 2.3×10 4 and 1.2×10 4 cfu/g, in the same order. A total of 60 B. cereus group of bacterial cultures isolated from market dairy products were identified as B. anthracis 39(65%), B. cereus 6(10%), B. mycoides 13(21.7%) and B. thuringiensis 2(3.3%). Results also show that all tested 60 isolates could be plotted in different patterns from A to G, e.g. B. cereus (A), B. mycoides (B, C and D), B. thuringiensis (E) and B. anthracis (F and G).

Yeast classification is traditionally based on their physiological and biochemical profiles. Recently, molecular methods have been successfully applied to yeast strain typing and identification. The aim of this paper was to characterize four yeast strains isolated from dairy products by classical and molecular methods. The preliminary examination involved macroscopic appearances of colonies on solid media and microscopic feature of the cells. Physiological characterization was mainly performed by assessing the ability to use certain sugars semi-anaerobically, the ability to use organic compounds as sole carbon source for aerobic growth, urea hydrolysis, growth at high concentrations of glucose and the ability to growth at non-optimal temperatures (37°C and 42°C). From results obtained it could be stated that, although there were some variations in biochemical patterns all tested yeasts were classified either as S. cerevisiae or and G. candidum with 95-99 % of probability. For molecular identification only three specific primer pairs and one universal primer were used. The identification was carried out based on ITS 1 partial sequence, 5.8 S rRNA gene and ITS 2 complete sequence and large subunit rRNA gene sequence analysis. The results obtained showed that the product of S. cerevisiae scored 600 bp in lan (1and 2) using 5.8 S rRNA gene with primer ITS and NL2, while G. candidum scored 600 bp in lan (3and 4) using 18S rDNA gene with primer (18S ITS1-28S ITS 2). However, the sequence analysis of the four identified yeast strains was submitted to Genebank in the NCBI database. They have been accepted to be deposited and released in Genebank under four new accession numbers, actually KY441458, MF380234 for S. cerevisiae and MF383376, MF383368 for G. candidum strains. In conclusion, Strains were locally isolated from Egyptian resources to increase the additive value of the Egyptian microbial wealth.

The incidence of enterococci in Raw milk, Karish cheese, Ras cheese and Domiati cheese was investigated by using three different selective media. All isolated enterococci were identified on genus and species levels. Higher, minimum, and maximum log counts were obtained by using KF medium being 10 6-10 7 (min) and 10 8 (max). These figures were 10 3-10 5 (min) and 10 6 (max) by using BEA and CATC media. Accordingly, KF medium could be considered the best for detection of enterococci incidence. The obtained results showed that the isolated Enterococcus from milk and cheeses studied were identified as E. faecalis 26 (32.5%), E. faecium 25 (31.25%) and E. durans 29 (36.25%), respectively. Most identified E. durans was observed in Karish cheese (15 out of 20) , followed by Raw milk (9 out of 20) and only 3 and 5 E. durans were isolated from Ras cheese and Domiati cheese. On the other hand, most isolated Enterococcus spp. from Ras cheese (14 out of 20) were E. faecalis. However, approximately half (9 and 8 out of 20) of identified Enterococcus spp. from Domiati cheese and Raw milk were E. faecium. All isolated strains were identified by using the biochemical characteristics. The results showed that all tested isolates belonged to genus Enterococcus.

The using of four yeast strains (two cultures belonging to each S. cerevisiae and G. candidum) to withstand environmental conditions similar to the human digestion tract (probiotic criteria) were examined. The survival of these strains at low pH, in the presence of bile salt, in intestinal juice, also their ability to assimilate cholesterol were followed. However, the obtained results indicate that S. cerevisiae AAA3 and G. candidum GG1, may be promising candidate strains for use as probiotics. Thus, the potential role of these probiotic yeast cultures on serum lipid of rats was adopted. Twenty-four male albino rats were randomly and equally divided into four groups, six rats each. These rats were acclimatized on basal diet for 7 days before starting the experiment. The first group was fed on basal diet (cont. I), the second group was offered basal diet plus pasteurized buffalo's milk (6.5% fat). The rest two groups were fed on basal diet plus buffalo's milk in addition to either S. cerevisiae or G. candidum. Blood samples were collected at the beginning of the experiment (after adaptation period) and at the end of experiment. According to the result of serum analysis, total cholesterol and LDLcholesterol levels in rats fed on S. cerevisiae (group 3) were decreased by 23% and 31.59% respectively. While, the corresponding values for rats consumed G. candidum were relatively lower, actually 21.46% and 29.12% respectively. Moreover, serum triglycerides concentrations reduced by 4.79% and 5.30% for rats in group 3 and 4, respectively as compared with control 1. Furthermore, data obtained declared that rats fed on either S. cerevisiae or G. candidum reduced markedly the atherogenic indexes 1 and 2 by mean values of 11.52, 23.86% and 10.1, 21.49% respectively, as compared with control 1. Continuously, rats fed on both yeast strains showed significant antagonistic effect against either coliform or staphylococci, where the reduction in their populations, actually 10.57, 7.42% for group 3 and 8.30, 18.22% for group 4, respectively.

The main target of the present work is to screen three tested strains of Lactobacillus spp. for functional characteristics for probiotics. The potential probiotic characteristics of three Lactobacillus spp. strains were studied with regard to acid / bile tolerance and surviving in gastric / intestinal juices. Results obtained revealed that all tested lactobacilli strains showed much greater stability at different low pH values (1.5, 2 and 3), and normal growth at bile concentrations up to 1 % w/v, which recommended these cultures to use as probiotic bacteria. Moreover, data obtained declared that all tested Lactobacillus cultures were considered intrinsically tolerant to gastric and intestinal juices. The potential role of these probiotic Lactobacillus cultures on serum lipid of rats was studied. Twenty-five male albino rats were randomly and equally divided into five groups, five rats each. After an adaptation period of 7 days, the first group was fed on basal diet served as control I, the second group was offered basal diet + buffalo's milk plus one of the tested lactobacilli strains. At the end of the 28 days' experimental period, the rats were killed. However, blood samples were collected at the beginning and the end of experiment. From results obtained it could be concluded that supplementation of diets with fermented milk culture with either L. casei or L. rhamnosus resulted in noticeable decreases in total cholesterol, LDL-cholesterol and triglyceride contents. Moreover, heoretic indexes 1, 2 and l LDL/HDL ratio were markedly reduced in rats received fermented milk as compared with control treatment I (dry diet). In conclusion, fermented milk can decrease in the faecal counts of either coliform or streptococci.