The combination of seed dimensions, moisture content, and color were used to indicate microbial spoilage.
Increased water availability in cottonseed stored over time resulted in higher aflatoxin concentrations.
Cottonseed with high microbial levels and aflatoxin could be sorted and removed by size and true density.
Higher aflatoxin levels were correlated to lower true density.
Abstract. Aspergillus flavus is a common field and stored grain fungus that infects cottonseed and other protein-rich grains and oilseeds. This fungus produces aflatoxin, a toxic and carcinogenic mycotoxin, which is initially found in the field and then proliferates during storage as A. flavus metabolizes. When consumed, cottonseed contaminated with aflatoxin has an associated health risk for dairy and beef cattle and poses a cancer threat to humans. There is a need to separate and clean batches of cottonseed before processing. The objective of this study was to determine the key physical properties of contaminated and non-contaminated (healthy) cottonseed. Healthy fuzzy cottonseed (350 g) and cottonseed contaminated with 150 ppb of aflatoxin (350 g), with an initial moisture content of 8.3% dry basis, were stored at 25C and 85% relative humidity for 21 days. The properties of the healthy and contaminated fuzzy cottonseed after the 21-day storage period that were characterized included sphericity, surface area, individual seed mass, projected area, color, and volume. The presence of aflatoxin and fungus showed significant effects on the density (<1.3 g cm-3), dimensions (<9.8, 5.6, and 4.9 mm for major, intermediate, and minor diameters, respectively), surface area (<368.4 mm2), projected area (<56.7 mm2), and volume (<0.08 cm3) of fuzzy cottonseed. The results of this study provide measurements of physical properties that relate to separating cottonseed contaminated with aflatoxin and fungus during storage and before processing. Keywords: Aflatoxin, Aspergillus flavus, Fuzzy cottonseed, Physical properties, Storage, Surface area, True density.