Aspergillus flavus is the main xerophylic species in stored peanuts often resulting in contamination with aflatoxins (AFs) and cyclopiazonic acid (CPA). This study evaluated the relationship between storage of shelled peanuts under interacting abiotic conditions on (a) the temporal colonisation kinetics and cumulative respiration rates, (b) quantified the effect on dry matter losses (DMLs) and (c) quantify accumulation of aflatoxin B1 (AFB1) and CPA. Both naturally contaminated and inoculated peanuts with A. flavus conidia were stored for 7-days under different water activity (aw; 0.77-0.95) and temperature levels (20-35°C). Gas Chromatography (GC-TCD) was used to measure the temporal respiration rates (R) and the total accumulated CO2 production. Mycotoxin contamination was quantified at the end of the storage period by LC-MS/MS. There was an increase in the temporal CO2 production rates in wetter and warmer conditions in all treatments, with the highest respiration in the 0.95 aw treatments of stored peanuts + A. flavus inoculum at 30°C (2474 mg CO2 kg-1 h-1). The DMLs were modelled to produce contour maps of the environmental conditions resulting in maximum/minimum losses. Maximum mycotoxin contamination was always at 0.95 aw although optimal temperatures were different for AFB1 and CPA. Thus, 30-35°C was optimum for CPA and 25-30°C for AFs. A significant positive correlation (Spearman p<0.0001) were found between Log10AFB1 and Log10DML in both naturally contaminated stored peanuts (r 2 =0.7744) and that inoculated with A. flavus (r 2 =0.8464). Small dry matter losses (0.56%) resulted in AFB1 contamination above the EU legislative limits. Real time CO2 monitoring is a powerful tool to provide an early indication of biological activity, our results shower a correlation with high CO2 production fungal growth and mycotoxin accumulation. These results provide valuable information for the creation of a database for the development of a postharvest decision support system for determining relative risks of contamination with these mycotoxins in stored shelled peanuts. Highlights (3 to 5/ 85 character per bullet point including spaces)  Higher optimum temperature for A. flavus growth (30-35°C) than for AFB1 production (25-30°C)  Optimum cyclopiazonic acid production was at (30-35°C), with none at 0.90 aw  Dry matter losses varied from 0.3-17% at 0.90-0.95 aw in stored peanuts depending on the temperature.

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