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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Produce Safety and Microbiology Research » Research » Publications at this Location » Publication #394851

Research Project: Elucidating the Factors that Determine the Ecology of Human Pathogens in Foods

Location: Produce Safety and Microbiology Research

Title: Reduction of Aspergillus flavus and aflatoxin AFB1 on almond kernels using gaseous chlorine dioxide fumigation

item RANE, BHARGAVI - Washington State University
item Lacombe, Alison
item GUAN, JIEWEN - Washington State University
item LUCERO, LILLIAN - Former ARS Employee
item BRIDGES, DAVID - University Of California, Davis
item SABLANI, SHYAM - Washington State University
item TANG, JUMING - Washington State University
item Wu, Vivian

Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/5/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary: Almonds are a popular edible tree nut and offer numerous essential nutrients, and are primarily produced in California. A significant concern of the almond industry is product losses due to mold growth and subsequent toxin production under critical environmental conditions like high temperature and humidity. Therefore, this study focused on using gaseous ClO2 to reduce aflatoxin-producing A. flavus mold spores and toxin contamination on raw almond kernels. After treating 100 g of almonds inoculated with A. flavus, up to 99.6% of mold reduction and 84.4% of aflatoxin B1 reduction were obtained. There is little to no effect of the treatment observed on the kernels. The results indicate that gaseous ClO2 can be used by the almond industry as a dry and nonthermal treatment to enhance food safety and reduce economic loss.

Technical Abstract: The almond industry suffers product losses caused by mold growth and toxin contamination. Gaseous chlorine dioxide (ClO2) has the potential for postharvest reduction of mycotoxic Aspergillus flavus. In this study, almonds inoculated with A. flavus mold spores were fumigated with gaseous ClO2 for 1, 2, 3, 8, 12, and 24 h using a dry precursor sachet batch method. The headspace concentration ranged from 0.5-2.4 mg/L, depending on initial dosing and time. At its highest concentration, gaseous ClO2 demonstrated an 84.4% degradation efficiency of aflatoxin B1 (AFB1) with a reduction of 2.4 log CFU/g of A. flavus on almond kernels. Additionally, suppression of AFB1 continued after one-month storage at 4oC. No significant oxidative effect and color difference ('E) was observed on the treated kernels. The almond industry can apply gaseous ClO2 technology to reduce mold contamination and product losses.