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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Foodborne Toxin Detection and Prevention Research » Research » Publications at this Location » Publication #368090

Research Project: Biocontrol Interventions for High-Value Agricultural Commodities

Location: Foodborne Toxin Detection and Prevention Research

Title: Effect of blanching on aflatoxin contamination and cross-contamination of almonds

item Mahoney, Noreen
item Cheng, Luisa
item Palumbo, Jeffrey - Jeff

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/19/2020
Publication Date: 7/21/2020
Citation: Mahoney, N.E., Cheng, L.W., Palumbo, J.D. 2020. Effect of blanching on aflatoxin contamination and cross-contamination of almonds. Journal of Food Protection. 83(12):2187–2192.

Interpretive Summary: Blanching of almonds is performed to remove skins (pellicles) from kernels to be used in commercial baking and cooking. We examined whether aflatoxin levels of almonds, to which aflatoxin was added (spiked), were reduced by blanching. Aflatoxin in spiked almonds was reduced by 81% in kernels after blanching, and the remaining aflatoxin was recovered in pellicles (17%) and blanching water (38%). The remaining aflatoxin (25%) was "lost," probably by binding to almond components in the blanching water. Aflatoxin added to blanching water used for additional blanching could cross-contaminate uncontaminated almonds. The amount of "lost" aflatoxin bound by almond components in blanching water did not depend on water pH or blanching time. Aflatoxin reduction and "loss" by blanching of naturally contaminated almonds was more variable than in spiked nuts, suggesting a more complex interaction between aflatoxin and almond components when the nuts are contaminated naturally.

Technical Abstract: Blanching of almonds was examined for reducing aflatoxin content of contaminated nuts. Almonds with intact pellicles were spiked with aflatoxin B1 (AFB1) and blanched at 85°C. Following blanching, almond kernels and pellicles contained 19% and 17% of spiked AFB1, respectively. Blanching water contained an additional 38% of spiked AFB1. Post-blanching water spiked with AFB1 and used for subsequent blanching showed low-level cross-contamination of uncontaminated nuts (3.2% in kernels). Blanching temperature and contamination level had no significant effect on percentage of AFB1 recovered from almond kernels. AFB1 levels that were unaccounted for in mass balance of blanching components were presumed to be due to water-solubilized almond components and were independent of pH and blanching time. Blanching reduced total aflatoxins in naturally contaminated almonds by 13-76%, depending on almond quality as well as blanching time and temperature. These results indicate that the association between almond components and aflatoxin generated through mold contamination is more complex than in spiking experiments.