Reduction in fungal viability, mycotoxicity, and cytotoxicity in green coffee beans treated with plasma nitric oxide water.

Coffee ranks among the world's most consumed beverages, yet fungal contamination and associated mycotoxins (ochratoxin A (OTA)) remain major safety concerns. This study evaluated cold plasma generated nitric oxide continuously dissolved in water (plasma NO water, P-NOW) as a nonthermal approach for simultaneous fungal inactivation and OTA detoxification for green coffee beans (GCBs). A 15-min P-NOW treatment achieved >2 log reductions in Aspergillus species accompanied by strong inhibition of mycelial growth after 120 h. Fluorescence imaging and flow cytometry confirmed compromised membrane integrity and elevated intracellular reactive nitrogen species, indicating nitrosative stress-mediated fungal inactivation. Simultaneously, P-NOW treatment induced a 30-48% reduction in OTA levels. LC-MS-QTOF analysis confirmed the cleavage of the OTA amide bond into non-toxic metabolites, ochratoxin α and L-phenylalanine. Crucially, post-treatment cytotoxicity assays using MRC-5 and MDCK cell lines showed a marked recovery in cell viability (up to 94%), confirming the safety of the degradation products. Throughout the process, essential quality markers such as caffeine, total phenolics, and flavonoids remained preserved. These results demonstrate that P-NOW treatment is a residue-free, scalable technology capable of mitigating microbiological and chemical risks without compromising product integrity. Integrating P-NOW treatment into wet coffee processing offers a robust, environmentally compatible approach for enhancing the postharvest safety of high-value commodities.