Asmaa Badr Moustafa Badr Tahoun

Background: Bacillus cereus and Yersinia enterocolitica are implicated in foodborne diseases (FBD) which have major effects on human health, therefore it is considered as universal public-health disorders. Essential oils and essential oils Nano emulsions have a sufficient antibacterial performance against a variety of bacteria especially multi-drug resistant bacteria. Probiotics showed several health benefits via moderating the GIT microbiota and their metabolites. Aim: The study was designed for evaluating the biocontrol ability of cinnamon essential oil Nano emulsion and probiotics as natural antibacterial additives and reveal their bactericidal mechanism. Methods: 250 random samples (50 raw milk, 50 rice pudding, 50 kariesh cheese, 50 yoghurt and 50 ice cream) were purchased separately from different areas in Mansoura city, Egypt and exposed to bacteriological analysis. Results: Bacillus cereus was found with the highest mean value of 66x107 ± 1.3x108 CFU/g in raw milk and the lowest mean value of 28x107 ± 2.6x107 CFU/g in kariesh cheese while Yersinia enterocolitica were found in 64% of the total inspected samples with the highest incidence (84%) in yoghurt. The toxinogenic potential of the tested pathogens have been evaluated by multiplex PCR pointing nhe A and ces genes for Bacillus cereus isolates while targeting in Y. enterocolitica 16s rRNA, and YST gene. Different concentrations (0.17%, 0.25%, 0.5%, 0.8%, 1%, 1.5%, and 2%) of cinnamon oil Nano emulsion were employed in this study. CEO (Cinnamon essential oil) Nano emulsion had the highest reduction rate at a concentration of 1.5% in case of Bacillus cereus and 2% in case of Y. enterocolitica. Among different types of probiotics, the best one which showed inhibitory potential against Bacillus cereus and Y. enterocolitica was L. plantarum. Conclusion: L. plantarum and CEO Nano emulsion at a concentration of 2% have the highest reduction rate against Y. enterocolitica while, L. plantarum and CEO Nano emulsion at a concentration of 1.5% have the best antibacterial effect against Bacillus cereus. In conclusion, more attention is required for both safety and quality in dairy products through application of natural additives as essential oils and probiotics.

Salmonella enterica is one of the most common causes of foodborne illness worldwide. Contaminated poultry products, especially meat and eggs are the main sources of human salmonellosis. Thus, the aim of the present study was to determine prevalence, antimicrobial resistance profiles, virulence, and resistance genes of Salmonella Enteritidis (S. enteritidis) and Salmonella Typhimurium (S. Typhimurium) isolated from laying hens, table eggs, and humans, in Sharkia Governorate, Egypt. The antimicrobial activity of Biosynthesized Silver Nanoparticles (AgNPs) was also evaluated. Salmonella spp. were found in 19.3% of tested samples with laying hens having the highest isolation rate (33.1%). S. Enteritidis) (5.8%), and S. Typhimurium (2.8%) were the dominant serotypes. All isolates were ampicillin resistant (100%); however, none of the isolates were meropenem resistant. Multidrug-resistant (MDR) was detected in 83.8% of the isolates with a multiple antibiotic resistance index of 0.21 to 0.57. Most isolates (81.1%) had at least three virulence genes (sopB, stn, and hilA) and none of the isolates harbored the pefA gene; four resistance genes (blaTEM, tetA, nfsA, and nfsB) were detected in 56.8% of the examined isolates. The AgNPs biosynthesized by Aspergillus niveus exhibit an absorption peak at 420 nm with an average size of 27 nm. AgNPs had a minimum inhibitory concentration of 5 µg/mL against S. enteritidis and S. typhimurium isolates and a minimum bactericidal concentration of 6 and 8 µg/mL against S. enteritidis and S. typhimurium isolates, respectively. The bacterial growth and gene expression of S. enteritidis and S. typhimurium isolates treated with AgNPs were gradually decreased as storage time was increased. In conclusion, this study indicates that S. enteritidis and S. typhimurium isolated from laying hens, table eggs, and humans exhibits resistance to multiple antimicrobial classes. The biosynthesized AgNPs showed potential antimicrobial activity against MDR S. enteritidis and S. typhimurium isolates. However, studies to assess the antimicrobial effectiveness of the biosynthesized AgNPs in laying hen farms are warranted.

Cheese is considered as a healthy and complete nutrient that supports part of the human needs with protein, minerals, and vitamins. This study was conducted to examine the mold growth in four cheese types including Kariesh, Feta, Domiati, and Rumy retailed in Zagazig city, Egypt. In addition, isolation and identification of the different mold genera was further screened. Furthermore, the proteolytic and lipolytic abilities of the identified molds were screened. Rumy cheese samples followed by Kariesh cheese samples showed the highest total mold count. The prevalent mold genera were Aspergillus spp., Penicillium spp., Cladosporium spp., and Fusarium spp. Identification of the Aspergillus isolates revealed five species, namely, A. niger, A. flavus, A. fumigatous. A. ochraceous, and A. versicolor. The detected molds had clear in-vitro lipolytic and proteolytic activities. The public health significance of the isolated molds was discussed. Therefore, strict hygienic measures should be adopted during all manufacture steps of these kinds of cheese.

Residual content of lead (Pb), cadmium (Cd), copper (Cu), and zinc (Zn) in the retailed meat and dairy products in Egypt was estimated. Calculation of estimated weekly intake (EWI) and health risks was followed. Results revealed detection of tested metals in all samples at variable concentrations with higher Pb and Cd than maximum permissible limits. However, the calculated EWI did not exceed the provisional tolerable weekly intake established by the World Health Organization. Furthermore, calculation of the hazard ratio and index for mixed metal contaminants did not exceed one, indication that products consumption would not pose adverse effects on consumers.

Cheese is regarded as an essential dairy product that cover part of the human needs with vitamins and minerals. However, cheese is also implicated in many food poisonings outbreaks worldwide. This study conducted to estimate coliforms and E. coli, and to investigate the occurrence of shigatoxigenic E. coli in four cheese types mostly consumed in Zagazig city, Egypt. In addition, detection of coding genes for shiga toxins (stx1, and stx2) was further screened using PCR. Besides, antimicrobial susceptibility of the isolated E. coli was further examined. The obtained results revealed that Kariesh cheese had the highest coliforms and E. coli counts, followed by Rumy, Domiati, and Feta cheeses, respectively. The isolation rates of E. coli were 52%, 24%, 20%, and 8% in Kariesh, Rumy, Domiati and Feta cheeses, respectively. The identified E. coli serotypes were E. coli O55:H7, E. coli O86:H11, E. coli O78:H-, E. coli O111:H4, E. coli O127:H6, and E. coli O26:H11. The expression of shiga toxin-coding genes indicated that E. coli O55:H7 harbored only stx1, E. coli O111:H4, and E. coli O86:H11 harbored only stx2, E. coli O78:H-, and E. coli O26:H11 harbored both stx1, and stx2; however, E. coli O127:H6 did not express any of the tested genes. Antimicrobial sensitivity testing revealed multidrug resistance profiles, particularly among E. coli O86:H11, E. coli O78:H-, and E. coli O26:H11. Therefore, strict hygienic measures should be adopted during all manufacture steps of these kinds of cheese.

The objective of the present study was to estimate the seroprevalence of Brucella spp. in humans and cattle at Sharkia Governorate, Egypt. In addition, identification of Brucella spp. in milk samples by PCR and culture with the evaluation of the risk factors associated with Brucella spp. seroprevalence in humans were carried out. Overall, the seroprevalence of Brucella antibodies in the examined cattle was 23.8%, while in human participants it was 21%. The examination of 205 milk samples using PCR revealed that 6.3% were positive for B. abortus biovar 1 and the results were confirmed by culture methods. Multivariate logistic regression revealed that consumption of unpasteurized dairy products, occupational contact with animals, and knowledge about the disease are risk factors associated with infection in humans. This study documented the endemic status of brucellosis in Egypt. Hygienic measures and increased awareness about the disease are recommended to minimize the spread of infection from animals to humans.