Development of direct competitive enzyme immunoassay kit for the detection of streptomycin residues in chicken meat and feed (Pembangunan kit kompetitif enzim immunoassai secara langsung untuk mengesan sisa streptomisin di dalam daging ayam dan makanan ayam)

The development of a direct competitive ELISA method for the detection of streptomycin in chicken meat, organ and feed was studied. Comparative study between these methods and the imported commercial kits for detecting streptomycin was also described. Meat (muscle) spiked with streptomycin standard (50 and 100 ppb) was used to demonstrate the sensitivity of the method. The anti-streptomycin antibody titer obtained was 1:51,200. The linear concentration ranges for streptomycin standard curve were calibrated from 0 –100 ppb for both developed and the imported commercial kits methods. The immunoglobulin G (IgG) for streptomycin was found to be cross-reacted with two derivatives tested, dihydrostreptomycin and dihydroxystreptomycin. A 1% non-fat dry milk was chosen as the best blocking agent used to prevent nonspecific binding. In the recovery studies, 50 ppb and 100 ppb streptomycin levels gave high recoveries (90 – 98%) for both methods. The streptomycin levels in fresh meat, organ and feed were also determined. The imported commercial kits method could detect streptomycin at 151 ppb/g in muscle, 441 ppb/g in kidney, 553 ppb/g in liver and 51 000 ppb/g in feed. The streptomycin levels in muscle, kidney, liver and feed were not significantly different from the results determined by the developed ELISA kit. The developed ELISA method could detect concentration of 0 –128 ppb of streptomycin in meat sample and could be used to assay samples of meat, organ and chicken feed directly without tedious sample extractions. It can be used as a simple, quick method of antibiotic screening to rank bulk samples for further analysis and was comparable with the imported commercial kit. Keywords: enzyme immunoassay; streptomycin; chicken meat