الفهرس 
cover englishOnly 14 pages are availabe for public view
 |  | from | 264 |  |  |
| | | from | 264 | | |
Abstract
In the present study, fifty raw camel milk samples were randomly collected from six Egyptian Governorates and analyzed for isolation of Lactobacillus species. Isolates were identified using biochemical, morphological and molecular tools. Twenty two isolates (44%) were belonged to Lactobacillus species namely; 9 Lactobacillus plantarum, 7 L. acidophilus, 2 L. casei sub spp. pseudoplantarum, 2 L. fermentum, 1 L. brevis and 1 L. paracasei with a percentage of (18%), (14%), (4%), (4%) (2%) and (2%) respectively. Five isolates (10%) were identified as Clostiridium baratii, 6 isolates (12%) were identified as Atopobium vaginae, while 17 isolates (34%) were unidentified.
Determination of the antimicrobial properties of Lactobacillus species were conducted against several pathogenic microorganisms using four food borne bacteria; two Gram-positive bacteria Staphylococcus aureus and Listeria monocytogenes and two Gram-negative bacteria namely; Salmonella Typhimurium, Escherichia coli as well as one mould species; Aspergillus flavus. Results showed that L. plantarum was the most effective inhibitory organism, which can be used a probiotic with antibacterial and antifungal activities. All Lactobacillus plantarum isolates were subjected to polymerase chain reaction (PCR); the results proved that all L. plantarum isolates have recA gene as well as bacteriocin encoding genes (plantaricin E/F genes).
The antimicrobial activity of bacteriocin producing Lactobacillus spp. (L. plantarum, L. acidophilus, L. fermentum and L. casei sub spp. pseudoplantarum) and camel milk (desert and local farms) were compared with that of sodium benzoate in vitro against the above-mentioned pathogenic microorganisms. Results showed that desert camel milk possesses the highest antimicrobial activities against different pathogenic micro-organisms followed by bacteriocin producing L. plantarum. The preservation efficacy of bacteriocin producing L. plantarum in apple juice was evaluated and compared with that of sodium benzoate under different storage conditions (at room temperature and 4oC). The biopreservative effect of bacteriocin producing L. plantarum showed better results compared chemical preservative. The efficacy of different volumes of bacteriocin producing L. plantarum on aflatoxins production in Czapek’s Dox liquid media infected by (106 spores/mL) was determined by (HPLC). The result showed that the bacteriocin biodegradation rate for aflatoxins (B1, B2, G1 and G2) at volume of 2 ml was inhibited by (92%, 95%, 93% and 0%) respectively.