Aspergillus decontamination in hazelnuts: Evaluation of atmospheric and low-pressure plasma technology

The decontamination effects of non-thermal atmospheric-pressure (AP) and low-pressure (LP) plasma systems were investigated on hazelnuts artificially contaminated with Aspergillus parasiticus and Aspergillus flavus spores. Furthermore, AP-plasma treatment conditions were also optimized. Spore reductions of 5.6 and 4.7 log cfu/g in Aspergillus parasiticus and Aspergillus flavus, respectively, were achieved after 100 W-30 min of LP-air-plasma treatment. Similarly, 5.5 and 5.4 log cfu/g of reductions in Aspergillus parasiticus and Aspergillus fiavus, respectively, were achieved after AP-air-plasma treatment at 3000 L/h of gas flow rate, frequency of 25 kHz and reference voltage of 100% (655 W) for 5-cycles (1.7 min). Deformation of spores and loss of spore integrity after plasma treatments were demonstrated with scanning electron microscope (SEM). This study showed that LP and AP plasma treatments might be an alternative method for inactivation of aflatoxin- producing fungi.