Effect of ozone gassing time and stirring duration on peroxide value, microbial decontamination, aflatoxin detoxification and sensorial characteristics of dried pistachios

Aflatoxin contamination in agricultural products such as pistachios threatens human health. Ozone has intense antimicrobial activity against microorganisms. The effect of ozone-treated time (3,4 and 5 h) and stirring time (10, 15 and 20 min) on microbial, aflatoxin content, peroxide value, and sensory properties of aflatoxin contaminated pistachios were investigated in this study. The microbial test results also show a significant reduction of microbial load in ozone-treated samples. According to the results, ozone gas caused a significant reduction in aflatoxin levels in pistachio kernels. Aflatoxins B1, B2, G1, G2 and total which was 33.5, 1.5, 0.06, 0. 31 and 35.13 ppb in the control sample, reached 0 ppb after 5 h of ozone-treatment (15 or 20 min). The results show that the longer the ozone gas is gasified, the higher the peroxide value. The lowest and highest peroxide value was observed in the control and the ozone-treated sample for 5 h (stirring the samples every 20 min), respectively. All peroxide values were below the allowable limit (1 meq/kg). The results of sensory evaluation show that ozonation did not have a negative effect on the falvor, texture, and color score of pistachios, but only had a significant effect on the aroma of pistachios that were ozone-treated for 5 h. According to results, 3 h of ozonation and stirring of pistachios every 20 min is recommended as the best treatment for reducing microbial load, aflatoxin content, peroxide value and maintaining the sensory properties of dried pistachios.