Low-temperature damp corn storage with and without chemical preservatives
Freshly harvested corn was stored from November 1997 to May 1998 and from October 1998 to May 1999. The initial moisture contents (w.b.) were 25% (1997) and 21% (1998). 1997 corn was stored without chemical treatments at 0°C, 5°C, 10°C and 15°C. Damp corn stored at 0°C for up to 160 days caused no change in mycotoxin levels and did not show visible mold growth or spoilage. Corn stored at 5°C exhibited gradual deterioration and increased zearalenone level after 50 days. Corn stored at 10 and 15°C showed rapid deterioration with very significant mold growth and spoilage. Trichothecenes and fumonisin mycotoxins were detected at low levels in fresh corn, but these compounds did not appear to either increase or decrease with storage. The 1998 corn was stored with chemical preservatives potassium sorbate (PS) and sodium hexametaphosphate (SHMP) at 0.5% and 1.0% concentration (w/w)) at 0°C and 5°C. Stored corn showed no change in mycotoxin levels for zearalenone, trichothecenes and fumonisins, whether treated with preservatives or untreated. PS and SHMP affected CO2 evolution rate in incubated samples, an indicator of mold respiration. PS showed more efficacy than SHMP.