Digital Repository for Department of Food Hygiene

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)