Postharvest mitigation of pesticide residues in black pepper (Piper nigrum L.): Mechanisms, processing efficacy, quality trade-offs, and future perspectives

Black pepper ( Piper nigrum L.) is an economically important export commodity, but pesticide residues may compromise food safety and market access under increasingly stringent maximum residue limits. Residue mitigation is particularly challenging because the wrinkled surface, wax-containing tissues, low moisture content, and hydrophobic constituents of dried peppercorns may promote pesticide retention and restrict treatment accessibility. This review critically evaluates conventional postharvest operations, including washing, drying, steam treatment, and storage, alongside emerging technologies such as ozone, cold plasma, plasma-activated water, ultrasound-assisted washing, and advanced oxidation processes. Particular attention is given to treatment mechanisms, pesticide physicochemical properties, residue location, process conditions, evidence strength, transformation-product formation, and effects on piperine, essential-oil yield and composition, color, aroma, and antioxidant properties. Although several emerging oxidative and mass-transfer-enhancing technologies are mechanistically promising, direct evidence for black pepper remains scarce, and removal efficiencies obtained from other commodities cannot be quantitatively extrapolated without matrix-specific validation. Future research should prioritize field-incurred residues, pesticide-specific processing factors and degradation kinetics, residue mass balance, transformation-product identification and toxicological assessment, and pilot-scale validation. Effective strategies must balance residue mitigation, microbial safety, quality preservation, resource efficiency, and economic feasibility.