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Relationship of Shelled Corn Fungal Susceptibility to Carbon Dioxide Evolution and Kernel Attributes¹

¹Purdue College of Agriculture Research Publication 2007-18114. ²Agricultural and Biological Engineering, Dept. Purdue University, W. Lafayette, IN 47907-2093. ³Corresponding author. E-mail: strosh@ecn.purdue.edu ⁴Retired from the Grain Marketing and Production Research Center, Manhattan, KS.

Fifty-one samples of shelled corn were rewetted to 21% wb moisture content (MC) and evaluated for susceptibility to fungal invasion using ergosterol measurements and a test kit that measures carbon dioxide (CO₂) evolution. The sample attributes measured were percent germination, electrolyte leakage after soaking in deionized water, percent fines, and percent kernel infection. The difference in ergosterol content before and after incubation at 24°C was used as the standard measure of fungal growth. Differences in CO₂ evolution among the samples were consistent with expectations for fungal growth based on storage history. The coefficients of determination (r²) for the linear regression of ergosterol difference with CO₂ kit readings were 0.46–0.60. All were statistically significant (α = 0.001) and r² values were slightly greater when four high-oil corn samples were removed. These results indicate that the CO₂ test can be used to assess fungal susceptibility of rewetted shelled corn, which may also be indicative of its susceptibility before rewetting. The linear regressions of kernel attributes with ergosterol difference (48 < n < 51) that were statistically significant included percent germination, r² = 0.49 (α = 0.001); electrolyte leakage, r² = 0.27 (α = 0.001); and percent fines determined with a 4.76-mm sieve, r² = 0.12 (α = 0.05).