The effect of sodium hydroxide and urea on some storage properties of moist grain

Abstract

SummaryStorage of high moisture grain treated with NaOH in various concentrations and with and without urea showed that while untreated moist grain (17–26% moisture) deteriorated during storage, grain treated with urea and with various concentrations of NaOH had few bacteria and fungal propagules, and was considered safe for feeding. When the grain was treated with NaOH at 35 g/kg air dry weight, there were less than 102·6bacteria and fungal propagules/g. Similar results were obtained when grain was stored in large batches in an open shed, although at 20 g NaOH/kg grain there was some deterioration after 6 months.Mouldy grain treated with NaOH showed an immediate decrease in both fungal propagules and bacteria from about 108to 104/g.The possibility of using urea to preserve grain was examined in a 5 months storage trial with urea concentrations varying from 0 to 20 g/kg. With 5 g urea/kg grain there was an immediate decrease in the numbers of bacteria and fungal propagules and the results suggest that 10 g/kg would be safe for storage.The mechanisms of the preservation effects of NaOH and urea are discussed.