Effect of Grain Moisture Content on the Occurrence of Aflatoxin in Stored Ear Maize

Abstract

To study the effect of moisture content on the contamination of aflatoxin in stored ear maize, the experiment was conducted at Nakhon Sawan field Crops Research Center during early June October 1995 and 1996. Split plot design was employed with 3 replications. Main plots consisted of 2 maize varieties with different maturity Nakhon Sawan 1 (medium maturity) and CP-DK 888 (late maturity). Four levels of moisture content of ear maize at harvesing time (31, 28,25 abd 23%) were sub plots. Ear maize were stored in the storage under ambient conditions for 60 days. Samples for aflatoxin analysis were taken at 0, 15, 30 and 60 days during storage. The results showed that the storage of ear maize with the initial moisture content lower than 25% or the harvesting time longer than 120 and 128 days after planting in Nakhon Sawan 1 and CP 888 varieties respectively reduced the aflatoxin contamination. The aflatoxin levels at recommended harvesting were lower than 20 and 50 ppb for 30 and 60 days respectively. In high moisture ear maize (25-33%), the saving storage period from aflatoxin contamination (lower than 20 ppb) was 15 days after harvesting.