Validation of a residue analysis method for streptomycin and tetracycline and their food safety evaluation in pomegranate (Punica granatum L.).

A single-step methanol extraction based method was developed and validated for simultaneous estimation of the residues of streptomycin and tetracycline group compounds in pomegranate fruits by LC-MS/MS. The limits of quantification for all target compounds were ≤0.005 mg kg(-1) with recoveries (%) at fortification levels of 0.005, 0.01, and 0.05 mg kg(-1) being within 90-116% (RSD ≤ 9%) and interday precision RSD ≤ 12% at 0.01 mg kg(-1). A field experiment on the dissipation of streptomycin and tetracycline (including 4-epimers) residues in pomegranate fruits with regards to field applications of the commercial formulation Streptocycline SP (streptomycin sulfate 90% + tetracycline hydrochloride 10%) at 200 and 400 g a.i. ha(-1) indicated preharvest intervals of 45 and 55 days for streptomycin and 12 and 15 days for tetracycline, respectively. The study will be useful in promoting effective residue monitoring and ensuring safe use of these antibiotics in managing bacterial diseases of pomegranate.