المستودع الرقمي لـكلية الطب البيطري

Thirty samples of Mozzarella cheese (15 made traditionally from raw milk in Tripoli city (Libya) and other 15 imported samples sold in markets related to different brand names) were examined bacteriologically for their total bacterial count, psychrophilic count, coliform count (MPN/g), presumptive Staphylococcus aureus count, as well as enterococci count. Higher counts were found in locally manufactured Mozzarella cheese. Salmonellae were absent in all examined samples for both types, while Escherichia coli were isolated from 3 samples (20%) of locally made samples. According to the suggested Libyan Standards of such samples, most of examined locally manufactured Mozzarella cheese samples were found unacceptable.
Hesham Taher Naas(1-2007)

The objective of this study was to determine the antimicrobial activity of proteolytic, meat-tenderizing enzymes (papain and bromelain) against E. coli and L. monocytogenes at three different temperatures (5, 25 and 35°C). Two overnight cultures of E. coli JM109 and L. monocytogenes were separately suspended in 1% peptone water and exposed to a proteolytic enzyme (papain or bromelain) at three different temperatures. Bromelain concentrations (4 mg/ml) and (1 mg/ml) tested at 25°C against E. coli and L. monocytogenes, respectively, were the most effective concentrations tested reducing populations by 3.37 and 5.7 log CFU/ml after 48 h, respectively. Papain levels of (0.0625 mg/ml) and (0.5 mg/ml) were the most effective concentration tested at 25°C against E. coli and L. monocytogenes, respectively, reducing populations by 4.94 and 6.58log CFU/ml after 48h, respectively. Interestingly, the lower papain concentration tested (0.0625 mg/ml) was more effective than the higher concentration (0.5 mg/ml) against E. coli at all three temperatures. As expected, the temperature was directly related to enzyme efficacy against both E. coli and L. monocytogenes.
Hesham Taher Naas(1-2013)

Background: This study was conducted to investigate the presence of Bacillus cereus in meat, meat products, and some seafood in Libya. Materials and Methods: One 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 using polymerase chain reaction (PCR) and partial sequencing of 16S rDNA techniques. Results: Of 131 samples, only 38 (29%) isolates were found to be B. cereus based on their cultural characteristics on Mannitol Egg‑Yolk Polymyxin (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 using PCR and partial sequencing of 16S rDNA technique and confirmed to be B. cereus. The confirmed B. cereus strains were tested for their antibiotic sensitivity profiles and showed a high percentage of multiresistance phenotype. Conclusions: The results provide a 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.
Hesham Taher Naas(6-2018)

This study determined the efficacy of actinidin and papain on reducing Listeria monocytogenes and three mixed strains of Escherichia coli O157:H7 populations on beef. The average reduction of E. coli O157:H7 was greater than that of L. monocytogenes and higher concentrations of either protease yielded greater reduction in bacterial populations. For instance, actinidin at 700 mg/ml significantly (p ≤ 0.05) reduced the population of L. monocytogenes by 1.49 log cfu/ml meat rinse after 3 h at 25 & 35 °C, and by 1.45 log cfu/ml rinse after 24 h at 5 °C, while the same actinidin concentration significantly reduced the populations of three mixed strains of E. coli O157:H7 by 1.81 log cfu/ml rinse after 3 h at 25 & 35 °C, and 1.94 log cfu/ml rinse after 24 h at 5 °C. These findings suggest that, in addition to improving the sensory attributes of beef, proteolytic enzymes can enhance meat safety when stored at suitable temperatures.
Hesham Taher Naas(12-2013)

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Abdulwahab Kammon(1-2022)

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Abdulwahab Kammon(1-2010)

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Abdulwahab Kammon(1-2010)

The hepatotoxicity and nephrotoxicity of chlorpyrifos (CPF) and imidacloprid (IMC) insecticides were experimentally studied in layer chickens, taking into account the patho-biochemical alterations. The LD50 values estimated were 41 mg/kg bw and 104.1 mg/kg bw for CPF and IMC, respectively. The plasma cholineesterase enzyme was severely inhibited in chickens given a single dose of CPF at a rate of 55 mg/kg bw via oral gavage, while it remained unchanged in chickens given IMC at rate of 139 mg/kg bw via similar route. The activities of liver function enzymes viz. AKP, ALT and AST were significantly increased in chickens of CPF and IMC groups. Uric acid level was significantly increased and cholesterol level was only significantly reduced in the plasma of chickens administrated CPF. Plasma glucose values in chickens given CPF as well as in chickens given IMC were significantly increased at (P
Abdulwahab Kammon(1-2010)