Transfer and processing fate of pesticide residues from feed to milk and dairy products: Kinetics, transformation and precision control.

Pesticide residues in dairy products present a growing food safety concern, as residues originating from feed, water, soil, and veterinary applications of pesticide-active compounds may enter the dairy chain, undergo metabolic or processing-induced transformations, and partition among milk and dairy products. Unlike plant-derived foods, milk is a structurally heterogeneous matrix in which fat globules, proteins, phospholipid-rich interfacial layers, and an aqueous phase create distinct microenvironments that influence residue partitioning and analytical recovery. This critical narrative review examines the fate of pesticide residues across the dairy value chain, integrating feed-to-milk transfer, deposition in animal body, processing factors, mass-balance approaches, transformation products, analytical advances, and decontamination technologies within a food-chemistry framework. Across the available evidence, pesticide transfer along the dairy value chain is governed by the physicochemical properties of the pesticide, the composition of the dairy matrix, and the processing conditions. Under the specific mild pasteurization conditions examined in dairy studies, many residues show limited concentration change, whereas cream separation, coagulation, fermentation and water loss can redistribute or enrich selected compounds in particular product fractions. Consequently, a decline in parent-residue concentration should not be interpreted as degradation or detoxification without consideration of product yield, fraction-specific mass balance, transformation products and analytical recovery. Recent targeted MS/MS, high-resolution mass spectrometry and suspect-screening approaches have improved quantification of current-use pesticides, polar residues and metabolites in dairy products; however, the characterization of transformation-product and the availability of matrix-resolved mass-balance data remain limited. Upstream prevention, risk-based feed control and matrix-specific monitoring therefore remain central to residue management, while biological, enzymatic and oxidative interventions require direct validation in the intended dairy matrix. To organize such evidence, this review proposes a six-gate decision framework encompassing validated quantification of parent-residue, yield-corrected mass balance, characterization of transformation-products, assessment of residual-toxicity, preservation of dairy quality, and industrial feasibility. This framework provides a structured basis for evaluating pesticide-residue fate and intervention effectiveness beyond apparent reductions in parent compounds, thereby supporting robust risk assessment and safer dairy.