Pesticide Residues in Marketed Raw Milk in El-Bayda City, Libya: A Cross-Sectional Screening Study and Analytical Quality Framework

Milk can carry pesticide residues through contaminated feed, water, pasture, or veterinary and agricultural use. This cross-sectional screening study examined 60 raw milk samples marketed in El-Bayda City, Libya (30 cow and 30 goat milk) for organophosphorus, pyrethroid, and organochlorine pesticide residues using QuEChERS extraction followed by GC–MS. Basic milk-quality parameters were also reported. Pesticide residues were detected in 26/60 samples (43.3%): organophosphorus compounds in 12/60 (20.0%), pyrethroids in 8/60 (13.3%), and organochlorines in 6/60 (10.0%). Detection frequency was 46.7% (14/30) in cow milk and 40.0% (12/30) in goat milk; the difference was not statistically significant using the reported 2×2 data (χ²=0.27, p=0.60). Samples classified as residue-detected had lower reported mean fat and protein values and higher titratable acidity than residue-free samples, but raw data were unavailable and a causal effect cannot be inferred. Four analyte means were supplied (chlorpyrifos, diazinon, cypermethrin, and DDT), but regulatory exceedance was not evaluated because the applicable residue definitions, regulatory source/date, sample-level concentrations, limits of detection and quantification, recoveries, and measurement uncertainty were not provided. The study therefore establishes a local screening signal that justifies validated quantitative surveillance rather than a compliance or health-risk conclusion. A strengthened monitoring framework is proposed, including matrix-matched calibration, recovery verification, traceable MRL selection, and linked farm-to-market sampling