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In this study, 120 lactic acid bacterial strains from different fermented dairy products as well as 10 bacterial intestinal isolates were evaluated for in vitro and in vivo degradation of various food azo dyes. Of these isolates, lactic acid bacteria (LAB) strains 13 and 100 and the intestinal isolates Ent2 and Eco5 exhibited 96-98% degradation of the tested food azo dyes within 5-6 hours. High performance liquid chromatography mass spectra of sunset yellow (E110) and carmoisine (E122) anaerobic degradation products by the intestinal isolates showed that they were structurally related to toxic aromatic amines. For an in vivo study, eight groups of rats were treated for 90 days with either the food azo dyes or their degradation products. All groups were kept for a further 30 days as recovery period and then dissected at 120 days. Hematological, histopathological, and protein markers were assessed. Rats treated with either E110/E122 or their degradation products exhibited highly significant changes in red blood cell count, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and white blood cell count. In addition, alanine and aspartate aminotransferases, amylase, total bilirubin, blood urea nitrogen, creatinine, glucose, total protein, and globulins were significantly increased. Furthermore, marked histopathological alterations in the liver, kidney, spleen, and small intestine were observed. Significant decreases in inflammation and a noticeable improvement in the liver, kidney, spleen, and small intestine of rats treated with LAB and food azo dyes simultaneously were observed. Finally, these results provide a reliable basis for not only a better understanding of the histological and biochemical effects of food additives, but also for early diagnostics. In addition, LAB strains 13 and 100 may play an important role as potential probiotics in food and dairy technology as a probiotic lactic acid starter.

Objective: To investigate the true incidence of Bacillus cereus (B. cereus) in food and children diarrhea cases. Methods: A total of 110 samples of various dairy products such as raw milk, long life pasteurized milk, yoghurt and infant powdered milk formulas, raw rice, and feces were examined for the presence of B. cereus by selective plating on mannitol-egg-yolkpolymyxin agar. Confirmation of B. cereus was carried out by biochemical tests and PCR. Identification of non-B. cereus isolates was carried out by 16S rDNA sequencing. Antimicrobial susceptibility was done by disk diffusion method. Results: Overall 35 samples (31.8%, n = 110) yielded Bacillus-like growth. Of which 19 samples (54.28%) were positive for B. cereus. All isolates were positive for enterotoxin production. No psychrotolerant B. cereus strains were detected in all samples. All B. cereus isolates were resistant to penicillin G, but susceptible to vancomycin, erythromycin and clindamycin. Conclusions: The results of this study confirm the importance of including B. cereus in disease control and prevention programs, as well as in routine clinical and food quality control laboratories in both Saudi Arabia and Egypt.

Probiotics are commensals with special characteristics that are essential for the development of the immune system, and may protect mucosal surfaces against pathogens. In this study, a total of 40 lactic acid bacteria (LAB) were isolated from different raw and fermented camel’s milk samples collected from Saudi Arabia (Makkah area) and Egypt (Fayoum), and tested for the probiotic properties. Among them, Pro 4 and Pro 7 isolates exhibited excellent probiotic potential including bile salt (0.2–0.6%), phenol tolerance (0.2–0.4%) and salt tolerance (0.0–10%). Furthermore, both strains exhibited antimicrobial activity against wide range of food-borne pathogens and Dermatophytes with average zone inhibition of 37.5, 35.5, 34.5, 27.5, 25 and 23.5 mm for Staphylococcus aureus, Trichophyton mentagrophytes, Escherichia coli, Listeria monocytogens, Candida albicans and Salmonella typhi, respectively. Furthermore, the in vivo study indicated that these strains significantly improved the mucosal immune responses through an increase in expression of TLR2 and IFNγ mRNA in mice intestine as well as increased the synthesis of polyclonal IgG, IgM and IgA in mice blood sera. Accordingly, due to these unique probiotic properties, both selected strains could be potentially used as probiotic starter cultures for fermented dairy foods as well as functional food and health products.

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Abstract:The antimicrobial activity of donkey milk was examined against 3 bacterial and 3 fungal strains selected on the basis of their relevance as human pathogens. All samples of donkey milk exhibited antimicrobial activity against dermatomycotic fungi and foodborne pathogen bacteria. The highest antimicrobial activity was recorded against Trichophyton mentagrophytes and T. rubrum with minimal lethal concentration of 32 mg/ml. In respect to foodborne pathogenic bacteria, Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus) were more sensitive to donkey milk than Gram-negative bacteria (E. coli) with minimal lethal concentrations of 32, 64 and 128 mg/ml respectively. Donkey milk kept about 60 to 62% of its antimicrobial activity against B. cereus and S. aurous respectively, after digestion with pepsin (2 mg/ml), suggesting that the fatty acids of donkey milk has the highest antimicrobial effect. While the antimicrobial activity against dermatomycotic fungi and Gram-negative bacteria not affected after digestion with pepsin. To explain the antifungal capability of donkey milk against dermatomycotic fungi, fatty acids were analyzed by gas chromatography. Fatty acids analysis indicated that the major constituents in donkey milk lipid are oleic (25.4%), palmitic (23.75%), linolenic (20.04%), arachidic (3.58%) and stearic (3.26%), which have antimicrobial activity. Finally, on the basis of results obtained in the current study, the antimicrobial activity of donkey milk against Staphylococcus aureus and dermatomycotic fungi, specially T. mentagrophytes and T. rubrum which frequently cause acute or chronic inflammatory tinea corporis; may be considered as a valuable natural product with novel functional protection properties in cosmetics and pharmaceutical industries.

This study investigated different amino acid-based surfactants (AASs), also known as biosurfactants, including sodium N-dodecyl asparagine (AS), sodium N-dodecyl tryptophan (TS), and sodium N-dodecyl histidine (HS) for their potential anticorrosion, antibacterial, and antidermatophyte properties. The chemical and electrochemical techniques were employed to examine the copper corrosion inhibition efficacy in H2SO4 (1.0 M) solution at 298 K. The results indicated their promising corrosion inhibition efficiencies (% IEs), which varied with the biosurfactant structures and concentrations, and the concentrations of corrosive medium. Higher % IEs values were attributed to the surfactant adsorption on the copper surface and the production of a protective film. The adsorption was in agreement with Langmuir adsorption isotherm. The kinetics and mechanisms of copper corrosion and its inhibition by the examined AASs were illuminated. The surfactants behaved as mixed-kind inhibitors with minor anodic priority. The values of % IEs gained from weight loss technique at a 500 ppm of the tested surfactants were set to be 81, 83 and 88 for AS, HS and TS, respectively. The values of % IEs acquired from all the applied techniques were almost consistent which were increased in the order: TS > HS ≥ AS, establishing the validity of this study. These surfactants also exhibited strong broad-spectrum activities against pathogenic Gram-negative and Gram-positive bacteria and dermatophytes. HS exhibited the highest antimicrobial activity followed by TS, and AS. The sensitivity of pathogenic bacteria varied against tested AASs. Shigella dysenteriae and Trichophyton mantigrophytes were found to be the most sensitive pathogens. HS exhibited the highest antibacterial activity against Shigella dysenteriae, Bacillus cereus, E. coli, K. pneumoniae, and S. aureus through the formation of clear zones of 70, 50, 40, 39, and 35 mm diameters, respectively.AASs also exhibited strong antifungal activity against all the tested dermatophyte molds and fungi. HS caused the inhibition zones of 62, 57, 56, 48, and 36 mm diameters against Trichophyton mantigrophytes, Trichophyton rubrum, Candida albicans, Trichosporon cataneum, and Cryptococcus neoformans, respectively. AASs minimal lethal concentrations ranged between 16 to 128 µg/ml. HS presented the lowest value (16 µg/ml) against tested pathogens followed by TS (64 µg/ml), and AS (128 µg/ml). Therefore, AASs, especially HS, could serve as an effective alternative antimicrobial agent against food-borne pathogenic bacteria and skin infections-associated dermatophyte fungi.

Abstract:In this study processed cheese was supplemented with either fresh or dried edible mushroom (Pleurotus ostreatus Hk 35), to improve its nutritional value, functional and sensory properties, chemical composition, amino acids content, and microbiological quality. Fresh mushroom was added to cheese blend in pieces and smashed form at levels of 0, 5, 10 and 15%, while dried mushroom was added at levels of 0, 1, 1.5 and 2%. Among all processed cheese treatments obvious differences (P≤0.01) were noticed in the organoleptic scores; the highest flavor scores (37.4, 37.3) were recorded for processed cheese supplemented with 1% and 1.5% mushroom powder, respectively. Significant differences (P≤0.01) were also recorded among chemical composition of the resulted processed cheese spreads. Moisture, ash and protein recorded the highest values in processed cheese supplemented with mushrooms compared to control. Moisture content in processed cheese control was 46.26%, while ranged from 47.39 to 53.72% in cheese spread supplemented with mushrooms. There was a significant difference (P≤0.001) in ash content of processed cheese spreads; the highest ash content (5.4%) was for processed cheese spread supplemented with 2% dried mushroom. Cheese spreads that contain mushrooms was high in protein/DM (31.20-36.36%) comparing to the spread of control (30.88%). There was also a significant difference (P ≤ 0.001) in the contents of all tested minerals in processed cheeses. The highest mean values of Ca, P, Mg and Zn was observed in control and processed cheese that contain mushroom powder. Regarding the pH values; processed cheese spreads that contain mushrooms have pH values ranged from 5.39-5.78, while in control ranged from 5. 47-5.63. Microbiological investigation showed that the total viable counts and spore former bacteria was lower in processed cheese supplemented with mushrooms than in cheese control. On the other hand, an increase in lipolytic and proteolytic bacteria was noticed during storage period. No yeast and molds were detected in the first month of storage for all processed cheese treatments.