Real-time CO2 monitoring for early detection of grain spoilage and mycotoxin contamination.

Background: This study aimed to compare the use of real-time CO₂, temperature (T) and relative humidity (RH) sensors as indicators of stored grain quality management, specifically for early detection of mould activity and mycotoxin contamination. Initial experiments were conducted using mini-silos containing naturally contaminated wheat grain (1.5 kg) stored at different moisture contents of 15-30% (water activity, a_w = 0.78 to 0.98), to evaluate their effects on grain respiration.

Results: Respiration rates and dry matter losses increased with grain moisture content. A larger-scale, nine-month study was then conducted using two pilot-scale silos (2.5 t; 1400 cm diameter; 2050 cm height) equipped with ATEX-compliant CO₂/RH/T sensors. A 'wet pocket' was simulated by introducing water to a localised area to mimic a water ingress event. This led to a rapid rise in CO₂ levels while T remained relatively stable. Mycotoxin analyses of the affected and unaffected regions showed a clear increase in the concentration and diversity of mycotoxins, particularly aflatoxin B1, aflatoxin B2, deoxynivalenol, deoxynivaenol-3-glucoside and moniliformin, in the wet pocket area.

Conclusion: Real-time CO₂ monitoring provided a faster and more sensitive indication of spoilage and mycotoxin risk compared to T and RH measurements. This highlights the potential for developing early-warning systems for stored grain management based predominantly on continuous CO₂ monitoring. © 2025 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.