Peanut Aflatoxin: Impact of Postharvest Insect Infestation and Storage Systems

Effective postharvest management is crucial for the U.S. peanut industry, given the humid-subtropical climate that promotes insect pests, <i>Aspergillus</i> mold, and aflatoxin contamination in peanut-producing states. This study surveyed five conventional metal warehouses (CMWs) and thirteen flat storage facilities (FSFs) in northeastern, southeastern, and southwestern Georgia, USA, from December 2022 to July 2023. Peanuts were sampled monthly to assess the temporal abundance and diversity of storage insect pests, damage variables, and aflatoxin levels in farmers' stock peanuts. A monoclonal antibody-based affinity chromatographic assay determined the total aflatoxin levels in samples. The most common insect species, accounting for ~85.73 of the total captured, included <i>Cryptolestes ferrugineus</i>, <i>Tribolium castaneum</i>, <i>Ahasverus advena</i>, <i>Plodia interpunctella</i>, <i>Cadra cautella</i>, <i>Ephestia elutella, Liposcelis</i> spp., and <i>Lachesilla pedicularia</i>. Insect populations peaked in June and July, with similar diversity trends across CMWs and FSFs. Insect-damaged kernels, weight loss, discolored kernels, loose-shelled kernels, moisture content, and aflatoxin levels ranged from 3.02 to 11.45%, 1.11 to 3.60%, 2.11 to 11.20%, 1.56 to 4.91%, 6.89 to 8.85%, and 0.43 to 27.59 ppb, respectively. The high prevalence of insect pests, their damage capabilities, and the aflatoxin levels of infested peanuts highlight the need for an improved IPM strategy in warehouses to ensure safe and sustainable peanut storage in the USA.