Ochratoxin a Detection in Coffee: Matrix Inteferences and Implications for Food Safety Monitoring

The accurate monitoring of Ochratoxin A (OTA) in coffee, a globally traded commodity, is paramount for public health. However, the chemical complexity of the coffee matrix presents a significant challenge to analytical accuracy. This study systematically investigated the impact of six key coffee components, caffeine, caffeine, caffeic acid, chlorogenic acid, cafestol, acrylamide, and melanoidins, on OTA detection using two established methods: immunoaffinity cleanup coupled with HPLC-FLD and a commercial Lateral Flow Immunoassay (LFIA). The results reveal a pronounced method-dependency in matrix interference. In HPLC-FLD, caffeine and caffeic acid caused significant, concentration-dependent reductions in OTA recovery (to ~65-70%). Conversely, LFIA performance was most compromised by chlorogenic acid and melanoidins, which decreased recoveries to 48.5% and 35.7%, respectively. Molecular docking simulations indicated that stable non-covalent interactions (hydrogen bonding and π–π stacking) between OTA and specific interferents can sequester the toxin and hinder antibody recognition. Analysis of commercial Brazilian coffees confirmed these interferences, with notable discrepancies in OTA levels between methods. These findings demonstrate that matrix effects are not uniform but are dictated by the analytical platform's underlying principle. Consequently, this work underscores the necessity of matrix-specific validation for both conventional and rapid methods to ensure reliable OTA monitoring and robust food safety protection.