Control of n-nitrosodimethylamine in malt through the use of liquid/ gaseous sulphur dioxide.

O'Brien, T.J., Lukes, B.K. and Scanlan, R.A.

Abstract
The burning of sulphur in the malt kiln has proved to be effective for control of N-nitrosodimethylamine (NDMA) in the manufacture of barley malt. Since sulphur dioxide (sulphur dioxide) is the major product of combustion of elemental sulphur, direct injection of liquid/gaseous sulphur dioxide offers the same benefits as burning sulphur with the added advantage of precision control. Installation of sulphur dioxide injection system including storage evaporators, flow meters, recorders, and low level alarms has enabled accurate control of sulphur dioxide application. Treating the malt when it is most receptive to sulphur dioxide, through a staggered rate of application to whole malt produced in one, two and three deck kilns has resulted in NDMA levels from nondetectable to 5 ug/kg.
Keywords: kilning malt nitrosamine sulphur dioxide sulphuring