Impact of storage structures on peanut quality: Insect pests and aflatoxin risks in peanuts

In the United States, commercial bulk storage of peanuts mainly occurs in conventional metal warehouses (CMWs) and flat storage facilities (FSFs). It is unknown to the extent these structures foster conditions that promote storage insect pests, Aspergillus growth, and aflatoxin formation, which threaten peanut quality and safety. This study evaluated the distribution and abundance of storage insect pests, damage variables, ambient storage conditions, and aflatoxin residues in peanuts stored in different facilities (CMW: 5 and FSF: 13) at buying points in northeastern, southeastern, and southwestern Georgia. Peanuts were sampled monthly from December, 2022-July, 2023. Storgard II Sticky traps, Dome traps, and WB Probe traps baited with kairomones were also used to monitor insect pressure inside and outside the warehouses. An affinity chromatographic assay was used to determine total aflatoxin levels in peanuts. Liposcelis spp., Cryptolestes ferrugineus, Tribolium castaneum, Plodia interpunctella, Lachesilla pedicularia, Cadra cautella, Ahasverus advena, and Ephestia elutella accounted for ~85.73% of total insects captured. The diversity of insects captured in sieved-peanut samples and traps was similar in CMW and FSF, however, temperature and r.h. varied. Insect-damaged kernels, weight loss, discolored kernels, loose-shelled kernels, moisture content, and aflatoxin ranges across the sampling months were 3.02–11.45%, 1.11–3.60%, 2.11–11.20%, 1.56–4.91%, 6.89–8.85%, and 0.43–27.59 ppb, respectively. A significant (P< 0.05) positive linear correlation was found between peanut aflatoxin levels and most studied variables. This study underscores the necessity for effective monitoring strategies in commercial warehouses to ensure a safe and high-quality peanut supply while maintaining the economic viability of peanut storage operations.