The effect of using peracetic acid in the processing terminal to reduce microbial contamination of pistachio

Purpose: Pistachio is a crusial agricultural product in Iran, but its contamination with various micro-organisms can cause problems in production, consumption, and export. Peracetic acid is an antimicrobial substance that can eliminate a wide range of micro-organisms quickly. This study aimed to evaluate the effectiveness of peracetic acid in reducing microbial contamination of pistachios in processing terminals. Research method: Harvested pistachios were treated with concentrations of ۰ (control), ۱, and ۲% peracetic acid at the washing basin of the terminal. Then microbial growth, bacterial and fungal population, lipid percentage, and peroxide number of pistachio kernels were evaluated at ۰ and ۶ months after treatment. Findings: The results showed that both ۱ and ۲% peracetic acid inhibited bacterial and fungal growth by about ۱۰۰% and reduced microbial flora growth by more than ۹۰%. As there was no significant difference between ۱ and ۲% peracetic acid, the final recommendation is to use ۱% concentration. After ۶ months, the contamination level increased by about ۵%, possibly due to storage conditions and contamination in subsequent stages. Different concentrations of peracetic acid did not have a significant effect on lipid percentage or peroxide number of pistachio kernels. Research limitations: As the treatment time with peracetic acid in the washing basin is uncontrollable, this factor has been eliminated in this research. Originality/Value: The study confirms the importance of using peracetic acid in the terminals to reduce and control pistachio contamination without producing harmful by-products. Economic evaluation also showed that using ۱% peracetic acid for disinfecting pistachios in processing terminals is cost-effective.

Keywords:

Disinfectant , Lipid percentage , Microbial flora , Peroxide value