A prevalent bacterial intestinal infection with severe economic damage is salmonellosis. Our study was carried out to diagnose Salmonella from chickens and calves, to determine its resistance to antimicrobials’ phenotypic and genotypic characterization of integrons and β lactamase genes in the multidrug resistance of different Salmonella serotypes, and to detect the genetic relationship between Salmonella isolates collected from different origins using an ERIC PCR. In total, 200 samples from diseased chicken and diarrheic calves were obtained from 50 various farms from Kafr El-sheikh, Egypt. Salmonella poultry isolates were characterized as S. Typhimurium (3/8), S. Enteritidis (3/8), and S. Kentucky (2/8), but Salmonella isolates from cattle were S. Enteritidis (1/2) and S. Kentucky (1/2). When antibiotic susceptibility testing was completed on all of the isolates, it showed that there was multidrug resistance present (MDR). A PCR was applied for identifying the accompanying class 1 integrons and ESBLs from MDR Salmonella isolates (two isolates of S. Kentucky were divided as one from calf and one from poultry). Our results detected blaTEM and class 1 integron, but were negative for bla IMP, bla VIM, and bla SHV. An ERIC PCR was conducted for understanding the clonal relation between various β-lactamase-producing MDR Salmonella isolates. The same four previously mentioned isolates were also tested. The two isolates of S. Enteritidis isolated from poultry and calves had 100% similarity despite indicating that there were interactions between broilers and calves living on the same farm that caused infection from the same Salmonella strains, while the other two isolates of S. Kentucky showed only 33% serovarities.

This study aims to detect Clostridium botulinum and its control using natural leaf extracts of Citrus limon, Citrus sinensis, and Citrus unshiu in Egyptian fish products, e.g., canned tuna, canned sardine, canned mackerel, fesikh, moloha, and renga, as well the application of C. limon in tuna. Moreover, the antibacterial activity of the C. limon leaf extract was also estimated. In the water extract, ascorbic acid, total flavonoid content (TFC), and total phenolic content (TPC) were determined by volumetric, aluminum chloride, and Folin–Ciocalteu approaches, respectively. The antioxidant ability of the extract was analyzed in vitro via free radical scavenging (DPPH) and Ferric reducing assays. The results showed variability in the distribution of the total number of positive C. botulinum in fish samples from three different governorates under study, which were (24) Alexandria, (16) Beheira, and (17) Gharbia, out of the 120 tested samples in each governorate. Additionally, the findings revealed that all three Citrus extracts contain an appropriate number of secondary metabolites, with a sustainable presence of saponin and tannins in the C. limon extract. Furthermore, all Citrus extracts inhibited bacterial growth by increasing the inhibition zone, with C. limon being the best extract (25 mm) compared to C. sinensis and C. unshiu. The overall results showed the high antioxidant and anti-Clostridium powers (p < 0.05) of C. limon leaf extract, indicating its preservative activity in fishery products during storage. Finally, C. limon leaf extract can fight off C. botulinum and is considered a promising natural preservation candidate in ensuring safe and fresh fishery products.

Padina pavonica, Hormophysa cuneiformis, and Corallina officinalis are three types of algae that are assumed to be used as antibacterial agents. Our study’s goal was to look into algal extracts’ potential to be used as food preservative agents and to evaluate their ability to inhibit pathogenic bacteria in several meat products (pastirma, beef burger, luncheon, minced meat, and kofta) from the local markets in Alexandria, Egypt. By testing their antibacterial activity, results demonstrated that Padina pavonica showed the highest antibacterial activity towards Bacillus cereus, Staphylococcus aureus, Escherichia coli, Streptococcus pyogenes, Salmonella spp., and Klebsiella pneumoniae. Padina pavonica extract also possesses most phenolic and flavonoid content overall. It has 24 mg gallic acid equivalent/g and 7.04 mg catechol equivalent/g, respectively. Moreover, the algae extracts were tested for their antioxidant activity, and the findings were measured using ascorbic acid as a benchmark. The IC₅₀ of ascorbic acid was found to be 25.09 μg/mL, while Padina pavonica exhibited an IC₅₀ value of 267.49 μg/mL, Corallina officinalis 305.01 μg/mL, and Hormophysa cuneiformis 325.23 μg/mL. In this study, Padina pavonica extract was utilized in three different concentrations (Treatment 1 g/100 g, Treatment 2 g/100 g, and Treatment 3 g/100 g) on beef burger as a model. The results showed that as the concentration of the extract increased, the bacterial inhibition increased over time. Bacillus cereus was found to be the most susceptible to the extract, while Streptococcus pyogenes was the least. In addition, Padina pavonica was confirmed to be a safe compound through cytotoxicity testing. After conducting a sensory evaluation test, it was confirmed that Padina pavonica in meat products proved to be a satisfactory product.

Campylobacter jejuni is a Gram-negative bacterium which is considered as the most reported cause of foodborne infection, especially for poultry species. The object of this work is to evaluate the occurrence of C. jejuni in chicken meat as well its control via three types of sorghum extracts (white sorghum (WS), yellow sorghum (YS), and red sorghum (RS)); antibacterial activity, antioxidant power, and cytotoxicity of sorghum extracts were also assessed. It was found that C. jejuni is very abundant in chicken meat, especially breast and thigh. WS extract showed more effectiveness than both yellow and red ones. Lyophilized WS extract offered high total phenolic compounds (TPCs) and total flavonoid compounds (TFCs) of 64.2 ± 0.8 mg gallic acid equivalent (GAE/g) and 33.9 ± 0.4 mg catechol equivalent (CE)/g, respectively. Concerning the antibacterial and antioxidant activities, WS showed high and significant antibacterial activity (p < 0.001); hence, WS displayed a minimum inhibitory concentration (MIC) of 6.25%, and revealed an inhibition zone of 7.8 ± 0.3 mm; it also showed an IC₅₀ at a concentration of 34.6 μg/mL. In our study, different samples of chicken fillet were collected and inoculated with pathogenic C. jejuni and stored at 4 °C. Inoculated samples were treated with lyophilized WS extract at (2%, 4%, and 6%), the 2% treatment showed a full reduction in C. jejuni on the 10th day, the 4% treatment showed a full reduction in C. jejuni on the 8th day, while the 6% treatment showed a full reduction in C. jejuni on the 6th day. Additionally, 2%, 4%, and 6% WS extracts were applied on un-inoculated grilled chicken fillet, which enhanced its sensory attributes. In sum, WS extract is a promising natural preservative for chicken meat with accepted sensory evaluation results thanks to its high antibacterial and antioxidant potentials.

The study aimed to assess the possibility of molecular typing utilizing a gene exclusive to M. gallisepticum (MG) that encodes a phase-variable putative adhesion protein (PvpA). Based on size differences and nucleotide divergence of the C-terminus-encoding region, the pvpA PCR-RFLP assay was utilized to distinguish between vaccine F strains and M. gallisepticum isolates. The study found a high M. gallisepticum infection rate (66.6%, 100%, and 75.75%) in layer, broiler breeder, and broiler flocks, respectively, and a pvpA PCR-RFLP clarified that isolations were closely related to the vaccine F strain. The three M. gallisepticum isolates and the F-vaccine were evaluated for their pathogenicity and ability to spread in infected and in-contact chickens utilizing clinical symptoms, air sac lesions, PCR, and serological testing at 14 and 28 days after the experimental infection. Isolates sampled at the same time, in the same geographic area, and causing similar pathologic effects under field conditions revealed identical RFLP patterns and were closely situated in the phylogenetic development tree. The study found that in-contact birds in both vaccinated and infected groups showed positive PCR results at 14 days post-infection, indicating shedding and lateral transmission, and the immunity to M. gallisepticum field isolates and vaccination against the M. gallisepticum F strain was weak until 35 days post-infection. The study suggests that a pvpA PCR-RFLP assay can efficiently differentiate vaccine strains from field isolates, eliminating the need for culture isolation, and can also aid in the molecular epidemiology of M. gallisepticum epidemics by using sequence analysis or RFLP.