The influence of modified atmospheres and their interaction with water activity on the radial growth and fumonisin B1 production of Fusarium verticillioides and F. proliferatum on corn. Part I: The effect of initial headspace carbon dioxide concentration

The effect of modified atmospheres on the growth and fumonisin B1 production of Fusarium verticillioides and Fusarium proliferatum on corn is presented in a series of two papers. In this, the first part, the effect of initial headspace (IH) carbon dioxide concentration and its interaction with water activity (aw) on growth and fumonisin B1 production was evaluated. It was observed that at all aw values studied, increase in the IH CO2 concentration generally resulted in a decrease in the colony growth rate (g, mm day− 1) and maximum colony diameter (Dmax, mm) and an increase in the lag phase duration (λ, day). Although both aw and IH CO2 concentration had significant and synergistic effects on g, aw had the largest effect. As little as 10% IH CO2 completely inhibited the production of fumonisin B1 by F. verticillioides. F. proliferatum was more resistant and required 40, 30 and 10% IH CO2 at aw 0.984, 0.951 and 0.930, respectively, to completely inhibit fumonisin B1 production. These results demonstrate that modified atmospheres containing high CO2 levels could potentially be employed for the protection of corn from fungal spoilage and mycotoxin contamination during the post-harvest period.