Inactivation of aflatoxigenic fungi (Aspergillus spp.) on granular food model, maize, in an atmospheric pressure fluidized bed plasma system

• Aspergillus flavus and Aspergillus parasiticus spores were significantly inhibited.
• The inactivation efficacy was investigated using varying parameters.
• The native microbial flora of the maize grains was totally inactivated.
• The reduction was maintained with no occurrence of regrowth during the storage.
• The damage caused on Aspergillus spp. spore cells was demonstrated by using SEM.

Atmospheric plasma provides the advantages of high microbial inactivation that can be performed under ambient conditions; therefore, it is regarded as a potential alternative to traditional food preservation methods. The present work presents the results of a critical study conducted on the efficiency of a non-thermal atmospheric pressure fluidized bed plasma (APFBP) system used for decontamination of maize. Maize grains that were artificially contaminated with Aspergillus flavus and Aspergillus parasiticus spores were treated in APFBP system for 1–5 min at two differently designed fluidized bed reactors with air and nitrogen. Results indicate maximum significant reductions of 5.48 and 5.20 log (cfu/g) in Aspergillus flavus and A. parasiticus after 5 min air plasma treatment. The native microbial flora of the maize grains decreased to more than 3 log after 3 min APFBP treatment, and no viable cells were counted. During the storage of plasma treated maize samples at 25 °C for 30 days, the Aspergillus spp. spores log reduction was maintained with no occurrence of re-growth. Overall, this study shows that plasma treatment has a fungicidal effect on A. flavus and A. parasiticus spores associated with alterations in spore surface morphology and loss of spore integrity. APFBP can inactivate aflatoxigenic spores on maize grains and could be optimized to improve the safety and quality of produce.