How widespread and concerning is Ochratoxin A in wheat and flour? A systematic review and meta-analysis

Ochratoxin A (OTA), a highly toxic and thermally stable mycotoxin, poses a significant challenge to global food safety, particularly in wheat, a staple of human diets. This systematic review and meta-analysis investigated OTA contamination in wheat and flour across climatic zones and geographic regions between 2000 and 2023. This study found that, with reference to the Köppen-Geiger climate classification, the Arid zone emerged as the most affected, with a contamination rate of 53% (95% CI: 35–70%), followed by the Temperate zone at 30% (95% CI: 20–42%) and the Continental zone at 21% (95% CI: 10–33%). Minimal prevalence was observed in the Polar and Tropical zones. Regionally, Asia and Africa, largely situated within the Arid zone, reported the highest prevalence rates of 44% (95% CI: 30–59%) and 31% (95% CI: 15–50%), respectively. A notable disparity was found between wheat forms, with flour showing higher OTA contamination rates (41%, 95% CI: 29–54%) compared to whole grain (27%, 95% CI: 19–36%), attributed to increased mould growth during processing and inadequate storage conditions. Simulated average OTA concentrations in wheat and flour were deemed largely safe. However, values in flour approached regulatory limits, with 93.1% of samples meeting EU thresholds (5 μg/kg for grains, 3 μg/kg for flour). This study highlights the need for heightened vigilance in high-risk regions to ensure the safety of wheat-based food supplies and protect public health globally, emphasising the importance of stringent storage and processing practices to mitigate OTA contamination.