Administration of antibiotics or hormones to broiler chickens for therapeutic and performance-enhancing purposes may lead to deposit of residuals in their carcasses. This could be a potential human health hazard upon exposure to these residues. The objective of this study was to detect residue levels of tetracycline, streptomycin, sulfamethazine, chloramphenicol, trenbolon, estradiol-17ß, and testosterone in broiler chicken meat commonly marketed in the Sultanate of Oman. The Enzyme-Linked Immunosorbent Assay technique was used to detect residues in 128 broiler chicken breast muscles, representing various poultry processing companies from six countries representing four continents. Generally, samples contained various levels of residues of different antibiotic and hormones. Tetracycline levels ranged between 35 and 56 ng/kg (mean 45.9); streptomycin ranged between 30 and 155 ng/kg (mean 100.0); sulfamethazine levels ranged between 0.079 and 5.60 ng/kg (mean 1.07); trenbolon ranged between 0.70 and 3.12 ng/kg (mean 1.67); estradiol 17-ß ranged from 0.06 to 2.00 ng/kg (mean 0.70); chloramphenicol ranged from 5.00 to 74.00 ng/kg (mean 14.38); and testosterone ranged from 4 to 70 ng/kg (mean 25.53). There were significant differences in residue levels of antibiotics and hormones between the companies and countries. There were significant differences in antibiotic and anabolic agents' residues with the exception of trenbolon between continents. This study indicated that broiler chicken meat products available in the local market contained various levels of residues of several antibiotic and anabolic agents. Although levels of some of these residues did not exceed the maximum allowable limits, they still poise a human health hazard.
There has been an increasing awareness of the widespread drug therapy and the possibility of residues in meat and consequently the potential human health hazards associated with exposure to these residues. Many of these are now classified as carcinogenic, toxic and allergenic, which interfere with human natural physiological functions. The Enzyme-linked Immunosorbent Assay (ELISA) is one of the sophisticate techniques to detect residuals based on enzyme-labeled reagents. Therefore, investigations using ELISA technique to monitor residues of various drugs in meat products should be applicable to insure the safety of animal food products for human consumption.