Multiple antibiotic residue profiling of chicken eggs using Liquid Chromatography-tandem Mass Spectrometry

The current study aimed at the standardization and validation of a comprehensive multi-residue analytical method for detection of five antibiotics of 03 different classes viz. Spectinomycin sulphate, Chlortetracycline hydrochloride, Oxytetracycline hydrochloride, Erythromycin and Tylosin tartarate in chicken eggs. The egg samples were extracted using acetonitrile: water along with Na₂EDTA facilitated with clean-up using Oasis HLB cartridge. The extract was centrifuged, dried and reconstituted for final analysis applying the standardized Liquid Chromatography-tandem Mass Spectrometry (LC-MS/MS). The validation study was conducted in accordance with SANTE/11312/2021 guidelines wherein parameters evaluated included coefficient of regression (r²) ≥ 0.99, LOD and LOQ, average recovery percentage at three fortification levels (10, 30 and 60 μg/kg) and RSD< 20%, which were found within acceptable limits. Five antibiotics were successfully detected in all the 100 egg samples analyzed (One egg sample comprised of six eggs from same source) collected from local retail shops, supermarkets, backyard poultry and poultry farms in and around Mumbai city. The study revealed that Chlortetracycline hydrochloride and Oxytetracycline hydrochloride were detected in two and one samples from retail shops (6.66%), and supermarket (3.33%), respectively. Similarly, amongst backyard poultry samples tested, two samples were found positive for Spectinomycin sulphate (8.00%). No residues were detected in poultry farm samples. The mean concentrations of antibiotic residues were far below the prescribed Maximum Residue Limit (MRL) by various legislative agencies for all the samples. The study demonstrates the suitability of the developed method for analysis of multiclass antibiotic residue in eggs in order to ensure optimum food safety.