Purpose: The objective of this study was to determine the effects of combining gaseous ozone and storage temperature for decontaminating and preventing the growth of A. parasiticusin peanuts.
Methods: Peanuts were inoculated with spores of A. parasiticus and exposed to ozone gases of 0 (control), 40, 60, 80, and 100 μmol for 60, 120, and 180 mins. Treated peanuts were stored at 5, 18, and 25oC, and A. parasiticuscounts and thiobarbituric acid reactive substances (TBARS, a lipid oxidation indicator) were determined during storage.
Results: The initial level of inoculated A. parasiticus in peanuts was approximately 8 log CFU/g. After ozone treatments, a decrease of >7 log CFU/g of A. parasiticus was observed for treatments with 100 μmol ozone for ≥60 mins. During storage, mold growth on these treated peanuts did not occur at 5 and 18 oC. The effective ozone treatments for reducing A. parasiticus on peanuts and preventing its growth during storage were 100 μmol ozone with a 60-min exposure time and storage temperature of ≤18oC. These treatments also did not cause significant lipid oxidation in peanuts as indicated by the TBARS levels during storage.
Significance: The results indicated that ozone treatment combining with low temperature storage could effectively eliminate A. parasiticus contamination and growth on peanuts. The method may be incorporated into peanut processing to reduce the contamination and growth of molds on peanuts.