Meat is a plentiful food source that people really appreciate, since it fulfills their nutritional requirements, particularly for proteins. Red meat is derived from animals such as cows, sheep, goats, camels, deer, and others. White meat encompasses all sorts of poultry meat, fish, and marine creatures [1,2] Furthermore, the acquisition of proteins from animal products, such as eggs and milk, involves a financial commitment that ensures the well-being of the animals and thus enhances the nutritional value of the meal. Global efforts to ensure the safety of these products primarily revolve around preventing the spread of animal-borne diseases. [3] Additionally, measures are taken to mitigate the risks of existing environmental pollution and address both immediate and long-term transmission factors, as well as potential toxic effects. Prominent risk factors for human health include mycotoxins, heavy metals, nitrates, nitrites, hormones, pesticide residues, antibiotics, dioxins, polychlorinated biphenyls, genetically modified organisms, poisonous dyes, and melamine. Meat and its derivatives are often included in the everyday diet of many individuals owing to social customs, cultural diversity, affordability, as well as the wide range of options and palatable flavors. The health advantage of meat sets it apart as a valuable component of a well-rounded diet. Meat is a convenient and abundant source of protein, minerals, and some vitamins, including B and B12. Meat is a plentiful reservoir of several essential elements.[4] Hence, it is crucial to underscore the significance of ensuring its safety for human consumption [2]. Drug residues may occur because of the therapeutic or prophylactic administration of medications to animals. The occurrence of these residues in meat and its by-products may be attributed to the improper administration of these medications [3]. The issue of negative residues in animal products has garnered significant attention from several stakeholders, including both local and international health organizations [4]. It is evident that all waste, including medications, is expelled from the body, but some of it gets trapped because it is hard to break down or eliminate efficiently. This leads to the accumulation of waste in tissues and organs for an extended period, increasing the risk of it being consumed by individuals. This poses a significant threat to public health [5]. The presence of antibiotics in beef may cause hypersensitivity and tissue damage due to inflammation and immunological response. Additionally, it can contribute to the development of antibiotic-resistant bacterial strains in the digestive system [6]. Furthermore, there is a growing trend of antibiotic use in veterinary practices across several nations [7]. By increasing the degree of animal feeding [8], a consequence is seen. Various international organizations have released many declarations about the carcinogenic impact of these substances that persist in meat intended for human consumption. Antibiotics are synthetic substances that are designed to eradicate a broad range of disease-causing microorganisms. Each antibiotic is differentiated from the others based on its chemical makeup, and specific strains of these antibiotics are cultivated and manufactured.[5] By manipulating the fundamental structure of a substance, additional chemical structures may be added or removed.[6] Some well-known substances used in veterinary medicine for therapy and increasing production levels include 6-lactams, tetracyclines, aminoglycosides, lincosamides, macrolides, pleuromutilins, and sulfonamides. In the veterinary profession, this substance is administered to animals by several methods such as intravenous, intramuscular, or subcutaneous injection, oral ingestion through feed or water, topical application on the skin, or injection into the breast or uterus.[1] Each of these approaches results in the existence of residues at the injection sites[7]. Furthermore, the use of animal waste, such as excrement, in agricultural practices as a fertilizer or as an interception, due to contamination of feed in unsanitary farms, is a significant factor contributing to their accumulation and recycling. Antibiotics tend to accumulate in the flesh of animals, particularly cows. The detrimental impact of sheep on consumer health necessitates the need for vigilant monitoring of these items.[8] Hence, the study sought to elucidate the original understanding of their existence in sheep meat and then provide practical suggestions to mitigate this occurrence by outlining methods to identify their presence. During the production phase, guidelines and protocols are established to determine the standards for antibiotic production. Emphasis is placed on adhering to withdrawal periods before the cutting phase, allowing tissues to be free from any residual contents[1].

Studied surveys.

in Lebanon the prevalence of penicillin residues in the meat samples was 21.3%, though none was above the maximum residue level.[9] In another study to survey the percentage of antibiotic residues in lamb and mutton meat in the city of Erbil. In the period from July to December 2018, . The total percentage of antibiotic residue was 10.4% and 13.2%. The highest infection rate was detected in December, 22.2%. It was found that heat treatment and cooking for 45 minutes leads to the conversion of antibiotic residues into residues that are completely inactive against the deadly bacteria.[10]In the city of Dohuk, residues of multiple antibiotics were found in (77.27%) of the examined carcasses. The study attributed that local sheep meat sold in Dohuk Governorate generally contains antibiotic residues. The slaughtered animals may have been treated with veterinary medications and the appropriate withdrawal period was not observed before slaughter. [8]  In Ankara, Turkey.beef meat samples were examined randomly from local markets for analysis. Extraction and determination of quinolones were made by ELISA procedure. (45.7%) of meat samples  were positive for quinolones, respective.This study indicated that some beef meat sold in Ankara contains residues of quinolone antibiotics.[1] In Ethiopia About 48% of the edible tissues had oxytetracycline residue levels above the recommende dmaximum residue limits. This suggests that proper withdrawal periods were not respected before slaughter ofthe animals [11]

Sample collection

A total of 200 thigh sheep muscle  samples from carcasses of random age were collected from slaughter houses and malls in different retail markets in mosul city, during the period from September 2023 to June 2024. The collected samples were placed in separate plastic bags and transported to Medical Lab Tech Department Alnoor University. 

Preparation of the spore suspension

Spores suspension of Bacillus subtilis was prepared at desired concentration according to standard methods[2]. Briefly, Heavy inoculums of B. subtilis were introduced to the surface of a Nutrient agar plate (HiMedia, India). The plates were incubated at 30°C for 10 days to induce sporulation. After the incubation period, colonies were harvested into 10 mL of sterile normal saline and heated at 70°C for 10 minutes to kill the vegetative cells. The heated suspension was centrifuged at 3000 rpm for 10 minutes. The clear supernatant was discarded. Another 10 mL of sterile saline were added to wash off debris of vegetative cells. The mixture was concentrated at the same speed and duration. The process was repeated twice to obtain a pure suspension of endospores. Suspension turbidity was adjusted to match 0.5 McFarland standard solutions (≈1.5 × 108 CFU/mL).

Preparation of test plates

MullerHinton agar was prepared as recommended by the manufacturing company (HiMedia, India). After cooling to approximately 45°C, inoculum of 0.1 mL of spore suspension was introduced to each 100 mL of the agar before solidification. The molten agar was poured into petridishes and allowed to solidify at room temperature. Plates were used at the same day of preparation or held at refrigerator and used within one week.

Detection of antibiotic residues in samples

A previously published technique[2] was adapted for the detection of antibiotic residues in sheep samples. A discshaped meat sample of 2 mm in thickness and 8 mm in diameter was considered as suspicious one, and a zone less than 1 mm was considered as a negative result. The zone size around each positive sample was measured using Vernier caliper. Since no zone appeared in control samples, zones diameters of samples were recorded for evaluation.

Occurrence of antibiotic residues in beef samples

Out of 30 raw beef samples, 4 (13.3%) were positive for the presence of antibiotic residues (Inhibition zones diameter ranged from 2 mm to 8 mm). Table 1

Changes in rate of antibiotic residues during study period

The change in occurrence rate of antibiotic residues was monitored through study period. The highest rate of residues detection was observed in spring; April (24.1%) and March (24.1), while the lowest rate was found in February (14.2%). Table 2 summarizes the detection rates in temporal scale.

Table 1

Table 2. Relationship between months and occurrence of antibiotic residu.

The meat industry is a globally common industry that is rapidly evolving. On the other hand, it suffers from numerous risks, one of them antibiotics accumulation  in marketed meat.These compounds are essential components in agriculture and animal husbandry, but their usage pattern is expected to be high, exceeding 38.33%.[12] Regarding red meats (beef and lamb), the average acidity and fat content are higher than average in white meats, even though the protein content in white meats is higher than in red meats.[4] Furthermore, beef and lamb contain tightly packed muscle fibers, while poultry contains loosely packed fibers.[13] For this reason, our study focused on the residues of antibiotics in sheep meat in the city of Mosul as one of the examples of red meat. Another reason for our study is that many researchers in different regions of Iraq have addressed the study of their presence rates, while lacking updated information in Mosul. There is also a need to understand the latest scientific developments in this field to develop solutions to avoid their risks[1,2,8].

‎Our current study has concluded that slaughtered sheep meat intended for human consumption contains residues of antibiotics.[14] This study, which spanned from September 2023 to June 2024, revealed that 17% of the total 200 samples tested were found to contain antibiotic residues. This is a concerning percentage, as it has a negative impact on human health and increases the risk of contracting diseases due to the development of bacterial resistance against these antibiotics.[6] Consumers are at risk of serious illnesses, including infection with the MERSA in addition to hyper sensitivity reaction .[6]Comparing with other researchers, the percentage was found to be similar to what Al-Mashhadani found in his study in the Erbil region, where he mentioned that the accumulation rate in Erbil reached 13%.[2] Similarly, Dohuk also found a different percentage. researchers in Ethiopia and Lebanon[1,11,14.15].Their percentage was much higher than what appeared in our study. This can be attributed to the lack of proper pre-slaughter period commitment by breeders in areas with high accumulation rates or to the intensive and inappropriate use of antibiotics by farmers. A Sudanese study [15]  also revealed that the percentage of positive samples varied between %10 and %19 during the study period, with the highest proportions observed in May and the lowest in November. These findings are consistent with those reported by researcher [2]. Regarding the distribution of accumulation rates by month, researchers found that the highest rate was 24% in the summer, which aligns with this study.[16] The World Health Organization (WHO) recognizes that antimicrobial resistance is a global problem, and measures must be taken to prevent the spread of resistant bacterial species and practices that contribute to resistance development [17].The remnants of antibiotics in sheep meat samples did not differ from those in cattle, which reached 13.3%. This is an approximate percentage, and these results are consistent with an Egyptian study that found residues of oxytetracycline (OTC) in 10% of tested imported beef samples. In addition, another Egyptian report indicates that 16% of the raw meat tested was contaminated with antibiotics [19-22].Our study results were compared to data from studies that focused on detecting antibiotic residues in meat in Erbil during the year 2019, and showed a similarity between the results. In  April only 11% and lower percentage  in Jan &February but there is rise in our percentage in  May &Jun , this indicate the differentiation of the climate  during animal management between the  this cities.

1. Enhanced Monitoring and Regulation:

2. Establish stricter regulations and monitoring systems for antibiotic use in livestock to ensure compliance with recommended pre-slaughter withdrawal periods.

3. Implement regular screening programs for antibiotic residues in meat products to ensure food safety.

4. Develop educational campaigns to inform farmers about the risks of excessive and inappropriate antibiotic use and the importance of adhering to withdrawal periods.

5. Raise consumer awareness about the potential health risks associated with antibiotic residues in meat.

6. Promote the use of alternative methods for disease prevention and growth promotion in livestock, such as probiotics, prebiotics, and vaccines, to reduce reliance on antibiotics.

7. Encourage the adoption of best practices in animal husbandry, including improved hygiene and biosecurity measures, to minimize the need for antibiotics.

8. Conduct longitudinal studies to track changes in antibiotic residue levels in meat over time and identify factors contributing to seasonal variations.

9. Investigate the effectiveness of different intervention strategies in reducing antibiotic residues in meat and their impact on antimicrobial resistance.

10. Foster collaboration between regional and international research institutions to share data, methodologies, and best practices for controlling antibiotic residues in meat.

Participate in global initiatives aimed at addressing antimicrobial resistance and promoting sustainable agricultural practices.

The authors declare that they have no conflict of interest

No funding sources

The study was approved by the Department of Medical Laboratory Techniques,AL Noor University Mosul, Iraq.

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2. Al-mashhadany et al.; "Detection of antibiotic residues among raw beef in Erbil City (Iraq) and impact of temperature on antibiotic remains" 8.1 (2019) Pp1–6, https://doi.org/10.4081/ijfs.2019.7953.

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11. Agmas et al.; "Antimicrobial residue occurrence and its public health risk of beef meat in Debre Tabor and Bahir Dar, Northwest Ethiopia" 11.7 (2018) Pp902–8, https://doi.org/10.14202/vetworld.2018.902-908.

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17. Manyi-Loh et al.; "Antibiotic Use in Agriculture and Its Consequential Resistance in Environmental Sources: Potential Public Health Implications" 23.4 (2018) Pp795, https://doi.org/10.3390/molecules23040795.

18. Abdel-Mohsein et al.; "Tetracycline Residues in Intensive Broiler Farms in Upper Egypt: Hazards and Risks" 5.3 (2015) Pp48-58.

19. El Atabani et al.; "Oxytetracycline residues in marketed Frozen beef livers at Sharkia, Egypt" 26.1 (2015) Pp104–12.

20. Agmas et al.; "Antimicrobial residue occurrence and its public health risk of beef meat in Debre Tabor and Bahir Dar, Northwest Ethiopia" 11 (2018) Pp902, https://doi.org/10.14202/vetworld.2018.902-908.

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