Assessment of Tetracycline Residues in Broiler Chicken Meat Sold at Mwanakwerekwe and Darajani Markets in Zanzibar

Introduction: The increased use of antibiotics in livestock production, particularly poultry, has prompted serious public health concerns due to the possibility of antibiotic residues in the food supply chain. This study examined the levels of tetracycline residues in broiler chicken meat samples including liver, small intestine, and thigh muscle tissues collected from two major markets in Zanzibar namely, Mwanakwerekwe and Darajani. An enzyme-linked immunosorbent assay test was used to detect tetracycline residues in 90 broiler chicken samples from the two markets. Results: Tetracycline residues were detected in 91% (29) of liver samples, 72% (23) of small intestine samples, and 100% (26) of thigh muscle samples. The liver samples from Mwanakwerekwe and Darajani showed the highest tetracycline concentrations of 2413.8 μg/kg and 1375.7 μg/kg, respectively. The small intestine samples from Darajani market had the highest concentrations of 2867 μg/kg and 124.2 μg/kg from Mwanakwerekwe market. Thigh muscle samples showed lower but substantial quantities of tetracycline residues, with the highest concentration of 1600 μg/kg. Compared to the Codex Alimentarius Commission’s Maximum Residue levels (MRLs) of 600 μg/kg for liver samples and 1200 μg/kg for muscles. Overall, 69% of all samples exceeded the tolerated levels, especially liver and thigh muscle tissues. Small intestines had no reference standard from the Codex Alimentarius Commission (CAC) MRLs because it is not considered as a consumable part of a chicken. Furthermore, the investigation discovered that all samples exceeded the Acceptable Daily Intake (ADI) of 0 - 30 μg/kg for tetracycline residues, suggesting a public health concern to consumers. Conclusion: The findings highlight the need for urgent control measures and better monitoring of antibiotic usage in poultry production to ensure food safety and public health are safeguarded. The results also emphasize the necessity of strengthening antimicrobial stewardship programs through education and awareness to farmers and consumers on the potential risks of antibiotic residues in the food supply chain. The high levels of tetracycline residues in broiler chicken meat sold at Zanzibar’s markets demand immediate regulatory action to successfully implement MRLs and ADIs from the required authorities.