Khalid Ibrahim Sallam

This study evaluated the concentrations of mercury (Hg), arsenic (As), lead (Pb), and cadmium (Cd) in 270 fish muscle samples comprising 90 each of flathead grey mullet ( Mugil cephalus ), gilthead bream ( Sparus aurata ), and brushtooth lizardfish ( Saurida undosquamis ) collected from the Mediterranean Sea at Damietta, Egypt. The impact of common household cooking methods (grilling and frying) on toxic metal levels and the associated human health risks was assessed in 90 fish samples comprising 30 from each fish species. Fish samples were subjected to wet digestion using a nitric-perchloric acid mixture and analyzed with the atomic absorption spectrophotometer for heavy metal determination. Mean ± SE concentrations (mg/kg wet weight) of Hg, As, Pb, and Cd were 0.05 ± 0.004, 11.69 ± 0.72, 0.895 ± 0.14, and 0.046 ± 0.005 in raw flathead grey mullet; 0.069 ± 0.005, 12.38 ± 0.45, 0.865 ± 0.13, and 0.062 ± 0.004 in raw gilthead bream; and 0.145 ± 0.011, 8.215 ± 0.50, 1.012 ± 0.13, and 0.087 ± 0.006 in raw brushtooth lizardfish, respectively. Arsenic concentrations exceeded permissible limits in all examined samples, while Pb and Cd surpassed regulatory limits in substantial proportions of the tested fish. In contrast, Hg levels remained below the recommended limit in all samples. Grilling and frying generally reduced toxic metal concentrations in the three fish species tested; however, grilling increased As levels in brushtooth lizardfish by 8.2%. Dietary exposure was evaluated by comparing estimated daily intake (EDI) with available health-based guidance values, whereas potential non-carcinogenic risk for Hg, Pb, and Cd was evaluated separately using USEPA reference-dose-based target hazard quotients (THQs). Health risk assessment revealed that estimated daily intakes of all analyzed metals were below their provisional tolerable daily intake values. Total arsenic concentrations exceeded the applicable maximum permissible level in all examined fish samples. However, arsenic-specific non-carcinogenic and carcinogenic risk estimates were not derived because total arsenic was measured without determination of its inorganic fraction. The present findings demonstrate considerable contamination of fish from the study area, particularly with As, Pb, and Cd, and highlight the need for continuous monitoring, stricter environmental controls, and effective regulatory strategies to protect public health and ensure seafood safety.

Background/Objectives: Despite the widespread use of antibiotics in animal husbandry, limited data are available on the presence of antibiotic residues in beef consumed in Egypt. Therefore, the current study aimed to determine ciprofloxacin, oxytetracycline, and sulphadimidine residues in beef marketed in Ismailia, Egypt. Methods: A total of 300 beef samples (100 each of normally slaughtered carcasses, emergency-slaughtered carcasses, and imported frozen beef cuts) were collected and analyzed for ciprofloxacin, oxytetracycline, and sulphadimidine residues using high-performance liquid chromatography (HPLC). Dietary exposure and potential health risks were assessed using the hazard quotient (HQ). Results: The findings demonstrated that 27.7% (83/300), 37.0% (111/300), and 41.7% (125/300) of beef samples examined were contaminated with ciprofloxacin, oxytetracycline, and sulphadimidine residues, respectively. The mean concentrations (µg/kg) for ciprofloxacin, oxytetracycline, and sulphadimidine were 136.7, 245.5, and 209.7 in normally slaughtered beef; 260.2, 378.6, and 301.4 in emergency-slaughtered beef; and 242.8, 261.4, and 115.7 in imported frozen beef, respectively. Notably, 13%, 26%, and 22% of the samples analyzed exceeded the maximum residue limits (MRLs) established by the European Union and the Codex Alimentarius Commission for ciprofloxacin, oxytetracycline, and sulphadimidine, respectively. Emergency-slaughtered beef exhibited higher mean concentrations of antibiotic residues and a greater proportion of samples exceeding the MRLs. The HQ values of each antibiotic residue were higher in schoolchildren than in adults, with emergency-slaughtered beef samples exhibiting the highest HQ values for all three antibiotics. Conclusions: The detection of antibiotic residues, including concentrations exceeding established MRLs, particularly in emergency-slaughtered beef, highlights the crucial importance of complying with antibiotic withdrawal periods and rationalizing their use in veterinary medicine to protect public health.

This study investigated the prevalence, antimicrobial resistance profiles, virulence determinants, and heat tolerance of Enterococcus faecalis and Enterococcus faecium isolated from ready-to-eat (RTE) beef luncheon and sausage in Egypt. A total of 150 samples were analyzed, yielding 514 Enterococcus isolates, with contamination detected in all samples. Molecular identification revealed a predominance of E. faecium (71.2%) over E. faecalis (28.8%). High frequencies of virulence genes were detected, particularly gelE (95.7%) and ace (60.7%), indicating strong pathogenic potential. Antimicrobial susceptibility testing demonstrated widespread multidrug resistance, with high resistance rates to β-lactams, tetracycline (94%), vancomycin (62.5%), and rifampin (91%). Notably, 100% of E. faecalis and E. faecium isolates were classified as multidrug-resistant, with some strains exhibiting extensive or pandrug resistance. Vancomycin resistance genes (vanA and vanB) were detected in the majority of isolates, with vanA being predominant. Heat treatment experiments showed minimal reduction in bacterial counts after microwave heating (8.2 vs. 8.9 log₁₀ CFU/g of the control), although boiling of the cooked RTE sausage for 5 min achieved a significant (p < 0.01) but incomplete reduction in the Enterococcus count by 3.8 logs (5.1 vs. 8.9 log₁₀ CFU/g), indicating notable thermotolerance. Surviving isolates retained resistance and virulence traits. These findings highlight RTE meat products collected from Mansoura city as potential reservoirs of thermotolerant, multidrug-resistant enterococci, raising a potential public health concern and emphasizing the need for improved food safety measures and further nationwide studies. Although direct epidemiological links between foodborne isolates and clinical infections were not established, the presence of such strains raises a potential public health concern and underscores the need for improved food safety measures and further epidemiological investigations.

The widespread use of antibiotics in poultry production raises concerns about drug residues in chicken tissues and associated public health risks. Chicken tissue samples ( n = 180; 60 each from breast, thigh, and liver) were purchased from various poultry shops in Egypt and analyzed using high-performance liquid chromatography (HPLC). Residues of enrofloxacin, oxytetracycline, and sulfadimidine were detected in 51.67% (93/180), 71.67% (129/180), and 16.67% (30/180) of chicken samples, respectively. Interestingly, 54.84% (51/93) of enrofloxacin-positive samples, 55.81% (72/129) of oxytetracycline-positive samples, and 70% (21/30) of sulfadimidine-positive samples exceeded the maximum residue limits (MRLs). Among the 180 samples of each of chicken breast, thigh, and liver samples, 5% of each tissue type contained the three antibiotics tested, while 40% of chicken breasts and 50% of both thighs and liver samples contained two of the three antibiotics. HPLC analysis revealed mean concentrations of 90.4, 317.7, and 573.3 µg/kg for enrofloxacin, oxytetracycline, and sulfadimidine, respectively, in chicken breasts; 161.5, 964.1, and 47, respectively, in chicken thighs; and 1707.3, 10,625, and 3848.1, respectively, in livers. The estimated daily intake (EDI) for antibiotics analyzed in chicken tissue among consumers was between 0.012 and 0.590 µg/kg body weight/day. The Hazard quotient (HQ) values of enrofloxacin, oxytetracycline, and sulfadimidine ranged between 0.0006 and 0.050 for schoolchildren, 0.0003 and 0.022 for women, and 0.0002 and 0.021 for men, respectively. Among the different age groups of the Egyptian consumers, schoolchildren had the highest daily intake and hazard quotient values of antibiotic residues from chicken tissue. The HQ values for tested antibiotics indicated no significant health risk for either adults or children, although children showed relatively higher values. Overall, the findings highlight the need for strict antibiotic monitoring, with consideration of their withdrawal periods in the veterinary field, to ensure food safety and to protect public health.

Buffalo meat is widely consumed in Egypt; however, it may pose serious food safety risks due to microbial contamination during handling, preparation, and processing. This study investigated the prevalence and characterization of multidrug-resistant (MDR) enterotoxigenic Staphylococcus aureus in raw ground buffalo meat and ready-to-eat (RTE) kofta and liver sandwiches marketed in Mansoura, Egypt. S. aureus was detected in 62% (62/100) of raw buffalo ground meat, 41% (41/100) of RTE kofta, and 60% (60/100) of RTE liver samples, with an overall prevalence of 54.3% (163/300). All 660 isolates were confirmed as S. aureus via nuc gene detection, among which 46.8% (309/660) were mecA-positive and verified as methicillin-resistant (MRSA), and 21.8% (144/660) were vanA-positive and verified as vancomycin-resistant (VRSA). Enterotoxigenic strains were identified in 42.7% (282/660) of isolates, with the sea gene being most prevalent (67.7%; 191/282), followed by seb (58.2%; 164/282) and sec (39.7%; 112/282). The highest frequency of enterotoxigenic strains occurred in raw ground meat (47.2%), followed by kofta (45.1%) and liver (36%). Antimicrobial susceptibility testing against 15 antibiotics revealed that 7.6% (50/660) of isolates were extensively drug-resistant (XDR) with a MAR index of 0.9, while 82.9% (547/660) were MDR with MAR values between 0.3 and 0.7, indicating exposure to environments of intensive antibiotic use. The present findings highlight a high contamination level of buffalo meat products with MDR enterotoxigenic MRSA and VRSA, representing a significant public health hazard. Implementation of strict hygiene measures, wise antibiotic usage, and continuous surveillance is essential to control their dissemination through the food chain.

The presence of extensively drug-resistant and heat-resistant Enterococcus faecalis and Enterococcus faecium in ready-to-eat meat products poses a significant public health risk due to their ability to survive thermal processing, persist in the food chain, and disseminate antimicrobial resistance, thereby increasing the risk of foodborne transmission and limiting treatment options. This study evaluated the prevalence, heat-resistance, virulence, and antimicrobial resistance profile of Enterococcus isolated from ready-to-eat (RTE) meat products in Mansoura, Egypt. All (100%, 135/135) examined RTE samples (45 each of shawarma sandwiches, Hawawshi, and pastrami slices) were contaminated with Enterococcus . PCR targeting the sodA gene verified that 63.3% (171/270) of Enterococcus isolates were E . faecium and 36.7% (99/270) were E . faecalis . The gelE and ace virulent genes were detected in 71.1% and 65.2% of Enterococcus isolates, respectively. Absolute resistance (100%) of enterococcal isolates was found towards penicillin and imipenem, while 86.7%, 85.6%, and 41.9% were resistant to rifampin, vancomycin, and amoxicillin, respectively. All isolates were resistant to at least 4 antibiotics, and 96.3% were resistant to at least 6 antibiotics, with an average MAR index of 0.604. Interestingly, Enterococcus in RTE meat samples passed thermal microwave deactivation for 5 minutes, indicating a potent heat stability of this microorganism. The threat caused by virulent, heat-tolerant, vancomycin-resistant enterococci contaminating meat products highlights the risk associated with these pathogens. This emphasizes the urgent need for preventive measures and global strategies to control these emerging foodborne threats.

This study aimed to determine the toxic metal contents in thinlip grey mullet, sardines, and sand smelt, as well as the impact of cooking on the metal levels and their potential harmful effects on public health. Two hundred forty fish samples, comprising 80 each of the three identified species, were collected from the Mediterranean Sea at Damietta coast, Egypt and analyzed for arsenic, mercury, lead, and cadmium contents, which were detected at mean ± SE concentrations (mg/kg) of 2.29 ± 0.22, 0.119 ± 0.019, 0.651 ± 0.131, and 0.042 ± 0.007 in thinlip grey mullet; 1.68 ± 0.18, 0.098 ± 0.018, 1.011 ± 0.169, and 0.049 ± 0.008 in sardine; and 1.87 ± 0.16, 0.055 ± 0.057, 0.965 ± 0.186, and 0.052 ± 0.009 in sand smelt, respectively. Alarmingly, 100% of fish samples exceeded the permissible limit for As, while Hg levels were within the safe limits for all tested samples. Frying and grilling significantly reduced the metal levels. The target hazard quotient, total target hazard quotient in all tested fish samples, exceeded their approved limits for arsenic and lead, while the assessment of the cancer risk values for arsenic in all tested fish species surpassed the cancer slope factor, indicating potential public health risks associated with consuming such fish. This study highlights the need for strict control measures to limit contamination of aquatic resources, especially by arsenic and lead, and to ensure the safety of seafood for human consumption, protecting public health and reducing the risk of fish contamination.

Ground meat is highly perishable and has a short shelf life due to microbial contamination with food spoilage bacteria along with foodborne pathogens, which increases the risk of food poisoning. Controlling microbial growth by using chemical or synthetic food additives or preservatives is of great health concern. Natural, plant-derived antimicrobial food additives are safer alternatives. Therefore, the main objective of this study was to evaluate the antimicrobial efficacy of different forms and concentrations of clove against food spoilage and foodborne pathogens and to determine their ability to enhance sensory quality and extend the shelf life of buffalo meatballs during refrigerated storage. Clove oil (0.25, 0.50, and 1.0 g/kg), clove extract (0.5, 1.0, and 1.5 g/kg), and clove powder (2.5, 5.0, and 7.5 g/kg) were assessed against aerobic plate counts (APCs), psychotropic counts (PCs), and foodborne pathogens such as Staphylococcus aureus, Salmonella enterica serovar Typhimurium, and Escherichia coli O157:H7, artificially inoculated in buffalo meatballs. Clove oil, clove extract, and clove powder treatments showed a significant (p < 0.01) reduction in the counts of S. aureus, S. enterica serovar Typhimurium, and E. coli O157:H7 compared to control samples. Among all tested forms and concentrations of clove, clove oil at 1.0 g/kg proved to be the most effective against the tested pathogens, as by the end of storage (day 12), it achieved 5.3 and 5.56 log reductions in S. aureus and S. enterica serovar Typhimurium, respectively, along with complete reduction in E. coli O157:H7, followed by clove extract at 1.5 g/kg, which produced 4.2, 4.92, and 7.01 log reductions in the corresponding three foodborne pathogens. The results showed that different concentrations of clove oil and extract treatments applied effectively improved the sensory attributes (flavor, tenderness, juiciness, and overall acceptability) of buffalo meatballs, while the sensory properties of clove powder were considered unacceptable, as it alters the taste and smell of meat. The ground buffalo meat treated with different concentrations of clove oil, clove extract, and clove powder significantly reduced the growth of APCs and PCs during refrigerated storage, resulting in 1.5 to 2.6 log reductions with a prolonged shelf life ranging from 9 to 12 days. Overall effects on shelf life and meat quality showed that all clove forms significantly slowed microbial growth and extended the shelf life of buffalo meatballs to 9–12 days, in contrast to 6 days or less for the control. The findings indicate that clove oil and clove extract are promising natural preservatives capable of improving microbial safety, maintaining sensory attributes, and enhancing the overall quality of buffalo meatballs during refrigerated storage.

Heavy metals like lead, cadmium, and mercury can accumulate in meat and organ tissues, posing significant food safety and health risks. In the current study, 315 frozen imported bovine samples (105 each of muscle, liver, and kidney) collected from local markets in Sohag governorate, Egypt, were analyzed by atomic absorption spectrophotometry for the determination of mercury (Hg), lead (Pb), and cadmium (Cd) concentrations. The metals determined were investigated for their potential public health hazards in humans. The mean ± SE concentrations of Hg, Pb, and Cd in beef were 0.312 ± 0.058, 0.684 ± 0.105, and 0.030 ± 0.005, respectively, while the corresponding values in liver samples were 0.273 ± 0.054, 0.763 ± 0.106, and 0.056 ± 0.007, respectively, and in kidney samples were 0.167 ± 0.04, 0.716 ± 0.119, and 0.073 ± 0.014, respectively. Beef samples contained the highest Hg level, while liver samples contained the highest level of Pb, and kidney samples contained the highest level of Cd. More than half of the samples tested exceeded the permissible limits set by International and local food agencies for Hg and Pb; exactly, 62.9, 60, and 54.3% of muscle, liver, and kidney samples, respectively, exceeded the maximum limits of Pb, while 54.3 and 57.1% of muscle and liver samples exceeded the limit of Hg. In contrast, none of the tested liver or kidney samples exceeded the limit of Cd, although only 22.9% of the beef samples exceeded their maximal limit. Although the human health risks estimated in the current study for consuming the contaminated samples were low, high proportions of samples exceeded the permissible limit, and therefore, continuous monitoring of heavy metal residues in food, especially of animal origin, is of great significance.

In this study, Shiga toxin-producing E. coli (STEC) were detected in 64% of all tested buffalo meat samples, distributed as 62% of buffalo meat chops and 66% of ground buffalo meat. Six serotypes (O55:H7, O111:H8, O145, O157:H7, O26:H11, and O103:H2) were identified, of which, O55:H7 (37.26%) and O111:H8 (21.29%) were the most predominant. The eaeA, stx1, stx2, and EHEC-hlyA were detected by multiplex PCR in all E. coli isolates at different percentages, and multiple virulence patterns with stx2/stx1/eae were the most prevalent pattern indicating that the serotypes will be more virulent in pathogenesis. The isolates showed high resistance rates against Erythromycin (100%), Clindamycin (86.7%), Nalidixic acid (84.4%), Cefepime (73.4%), and Ampicillin (62.7%), Cefazolin (53.2%) and Tetracycline (51.7%) and most of the isolates (73%) were classified as multi-drug resistant (MDR). For the first time, we identified a high frequency of Cefotaxime-resistant (28.5%) and Colistin-resistant (16.3%) E. coli from buffalo meat and this becomes a huge problem because Cefotaxime and colistin are typically used as a last resort to treat complex infections caused by multidrug-resistant Gram-negative bacilli. The emergence of virulent and multidrug-resistant E. coli strains in food seriously threatens human health. This highlights the need for antimicrobial stewardship programs in developing countries like Egypt to minimize the spread and emergence of these strains and prevent their dissemination to humans.