Abstract:
Tetracyclines (TCs) are broad spectrum antibiotics which have been commonly used in veterinary for the purpose of prevention and treatment of infectious diseases. The widespread use of TCs could lead to TCs residues in animal-producing foods. To ensure food safety for the consumers, several authorities around the world have established the maximum residue limit (MRL) for TCs. Enzyme-linked immunosorbent assay (ELISA) is considered to be a good alternative because of its simplicity, rapidity, high sensitivity and specificity. The objective of this study was to evaluate the feasibility of using a monoclonal antibody in the preparation of an ELISA test kit for tetracycline detection. Four types of ELISA were prepared and tested for their sensitivities. It was found that Ab- captured direct competitive ELISA is the most suitable method with the average inhibition concentration at 50% (IC₅₀) and limit of detection (LOD) value of 2.63 ppb and 0.19 ppb, respectively. The detection range of the prepared test kit was from 2.5 to 100 ppb. In addition, the specificity of the test kit was also tested and found to cross-reacted with antibiotics in TC group between 19-86%. However, it did not cross-reacted with other tested compounds. The developed test kit was tested on honey. It revealed the % recovery of 91.64- 99.39%. Furthermore, comparative quantification of tetracycline using the developed ELISA test kit and LC-MS-MS technique showed that these methods gave comparable results. In addition, the intra-assay and inter-assay variations of the developed test kit were also investigated and found to be 1.94-8.35% and 12.75-17.94%, respectively. These indicated that the prototype test kit can be used to accurately and efficiently determine the amount of tetracycline.