Evaluating the combined toxicity of Penicillium mycotoxins in absorption, metabolism, and excretion systems.

Abstract

Penicillium mycotoxins, including ochratoxin A (OTA), citrinin (CIT), and cyclopiazonic acid (CPZ), frequently co-occur in food commodities, contributing to chronic low-level dietary exposure. However, current risk assessments often consider these toxins individually, overlooking potential interaction effects. This study evaluated the individual and combined cytotoxicity of OTA, CIT, and CPZ using human cell models representing key barriers of absorption (gastric and intestinal), metabolism (hepatic) and excretion (renal). The combination index-isobologram method was applied to characterize interaction dynamics. Ochratoxin A exhibited the highest toxicity across all cell types, followed by CPZ and CIT. Binary mixtures revealed strong synergistic interactions, particularly OTA:CPZ in liver cells and OTA:CIT in liver and kidney cells. Ternary mixtures primarily affected kidneys. High dose reduction index (DRI) values were observed at low inhibition levels, reaching 21.82-fold, indicating enhanced toxicity potential at dietary-relevant concentrations. Synergism was most pronounced at low inhibition levels (IC 10 ), representative of chronic dietary exposure, emphasizing the risk of real-world co-exposure. These results demonstrate that low-dose synergic interactions among Penicillium mycotoxins may enhance toxic risk under realistic exposure scenarios. Incorporating mixture effects into food safety risk assessment frameworks is therefore essential to better reflect chronic human exposure conditions. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.