The application of novel rotary plasma jets to inhibit the aflatoxin-producing Aspergillus flavus and the spoilage fungus, Aspergillus niger on peanuts

Abstract

The major safety risk of peanuts is contamination with aflatoxin. Cold atmospheric plasma (CAP) has been demonstrated to inactivate fungi effectively. In this study, a novel CAP device with a rotary jet system was used to inactivate the existing A. flavus and A. niger on peanuts. The initial inoculation levels were 6.39 and 5.83 log CFU/g of A. flavus and A. niger, respectively. After treatments at 180 W for 7.5 min and 200 W for 5 min, A. flavus was not detected. For A. niger, the treatments at 180 W for 10 min and 200 W for 5 min resulted in undetected population. Observation under scanning electron microscope revealed the fungal spores were evidently damaged. The growth of A. flavus and aflatoxin concentrations were significantly lower (p < 0.05) on the group treated with 200 W for 5 min than other treatment groups stored for 29 d. Oil quality indexes of the CAP-treated peanuts were maintained in the range of excellent grades. This study demonstrated CAP effectively inhibited fungal growth and toxin production without adversely affected oil quality.