Prevention of toxigenic fungal growth in stored grains by carbon dioxide detection

Abstract

The growth of toxigenic fungi can adversely affect grain quality and even produce mycotoxins of food safety concern, which should be sensitively monitored and controlled during grain storage. To establish the relationship between the growth of toxigenic fungi and their carbon dioxide (CO₂) production, the pattern of CO₂ concentration changes was studied during the fungal growth in grain. The results showed the CO₂ concentrations increased exponentially (r ≥ 0.96) during the growth of toxigenic fungi Aspergillus flavus, Penicillium sp. and Aspergillus ochraceus, which was different from the linear increase of CO₂ concentration produced by the non-toxigenic xerophilic fungi Aspergillus glaucus and Aspergillus restrictus. The acceleration of CO₂ concentration was found much earlier than the growth of toxigenic fungi, which would be useful for the prevention of grain spoilage. In addition, the CO₂ concentration changes were also determined in storage containers loaded with grain of different moisture content and significant correlation (p < 0.05) was found between changes of CO₂ concentration and fungal growth as well as mycotoxin production. The nonlinear increase of CO₂ concentration in stored grains could be considered as an indication of the rapid growth of toxigenic fungi and greater risk of microbial spoilage of grains. The results can provide a valid foundation for the prevention of toxigenic fungi and mycotoxin production in stored grains through monitoring the CO₂ concentration changes.

Keywords:

• mould
• grain spoilage
• carbon dioxide
• mycotoxin

Additional information

Funding

The authors gratefully acknowledge the National Basic Research Program of China [project number 2013CB127804], the National Natural Science Foundation of China [project numbers 31271948 and 31371850] and the Doctoral Scientific Research Start-up Foundation from Henan University of Technology [grant numbers 2012BS038 and 2012BS014] for providing financial support.