In this study, antibacterial, antioxidant and phenolic compounds of raisin extracts was evaluated. Different solvent extraction methods were utilized to extract phenolic compounds from raisin. The phenolic compounds of raisin extracts was determined using HPLC and three compounds were found, catechin, quercetin and rutin. The antibacterial activity of the acetonic extract was tested against four bacterial pathogens viz. Staphylococcus aureus, Pseudomonas aeroginosa, Salmonella typhimurium and Escherichia coli using both disk diffusion and minimum inhibitory concentration (MIC) methods. The acetonic extract exhibited the highest activity against Staphylococcus aureus with zone of inhibition of 14mm and the MIC of 25 mg/ml. However, there was a little activity against E. coli and S. typhimurium. The methanolic extract showed good antioxidant activity as indicated by 2,2-diphenyl-1-picrylhydrazyl free radical assay (DPPH). In conclusion, raisin contains potent phenolic compounds and their application might function as promising natural preservative and antimicrobial agents in food industry and also good antioxidant food that helps to minimize the risk of degenerative diseases. arabic
Yousef M Abouzeed, Ahmed MO Et Al. (12-2018)

Background: This study was conducted to investigate the presence of Bacillus cereus in meat, meat products and some seafood in Libya. Materials and Methods: A hundred and thirty one samples were collected from different geographic localities in Libya. The samples were subjected to microbiological analysis for enumeration and isolation of B. cereus by conventional cultural, biochemical and molecular identification by using PCR and partial sequencing of 16S rDNA techniques. Results: Out of 131 samples, only 38 (29%) isolates were found to be B. cereus based on their cultural characteristics on MYP medium, that included 30% beef, 38.2% beef products (minced, burger, kabab and sausage), 31.8% camel meat and 48% chicken products (burger, sausage, kabab and liver). However, B. cereus was not detected from mutton and seafood samples. Seventeen isolates were subjected to molecular identification by using PCR and partial sequencing of 16S rDNA technique and confirmed to be B. cereus. The confirmed B. cereus strains tested for their antibiotic sensitivity profiles and showed high percentage of multi-resistance phenotype. Conclusions: The results provide better understanding of B. cereus isolated from food of animal origin in Libya and suggest that meat and meat products might play an important role in the spreading of B. cereus through the food chain with antimicrobial resistance characteristics.
Salah M.Azwai(1-2018)

Abstract: This study was carried out to detect different coliforms members with special reference to the occurrence of the pathogenic Escherichia coli existing in raw cow`s milk and some dairy products. 105 samples (35 raw milk, 35 fermented milk, and 35 ricotta cheeses) were randomly collected from different markets in Tripoli-city /Libya. In this study, two methods for coliform counting were used. The first one was the most probable number technique MPN using liquid Lauryl Sulphate Tryptone broth (LST) with a three-tube series and the second method was the plate count method using violet red bile lactose agar VRBA. Also different techniques were used to find comparative results by using the BD phoenix system, the VITEK® 2 Compact system and KB003Hi25™ Enterobacteriaceae Identification Kit methods for coliform counts in raw milk, fermented milk and ricotta chesses. The coliform bacteria were positive in all 35 (100%) samples of both raw milk and fermented milk, while 33 (94.3%) samples out of 35of ricotta cheese by using MPN-technique. Whereas, Coliform bacteria were positive in 25 (71.4%) samples of raw milk, 34 (97.1%) samples of fermented milk and in 22 (62.9%) samples of ricotta cheese by using VRBA-technique. However, the fecal Coliform bacteria were recorded in 30 (85.7%) samples of raw milk, 32 (91.4%) samples of fermented milk and in 24 (68.6%) samples of ricotta by the used MPN-technique. Whereas, fecal Coliform bacteria were detected in 11 (31.4%) samples of raw milk, 19 (54.3%) samples of fermented milk and in only 9 (25.7%) samples of ricotta cheese by the VRBA-technique. Moreover, the most commonly identified important pathogenic bacteria Gram-negative isolated the highest overall incidence rate was for Escherichia coli 117(58.5%) and Klebsiella pneumonia spp pneumonia 47(23.5%) out of 200 randomly selected from 900 isolates. These findings results revealed that a high number of bacteria, which provide an evidence for the lack of milk hygiene either during milking or transporting and storages Statistical analyses revealed significant T-test at level P
خديجة مختار التواتي (2015)