EVALUATION OF CORRELATION BETWEEN WITHIN-BARN CURING ENVIRONMENT AND TSNA ACCUMULATION IN DARK AIR-CURED TOBACCO

Significant variability in cured leaf tobacco-specific nitrosamine (TSNA) content is commonly observed when sampling within dark air-curing barns. This variability may be due to inconsistency in the curing environment within different areas of the barn. A study was initiated in 2012 through support from a CORESTA Study Grant to evaluate if leaf TSNA content is related to microenvironmental conditions in the barn. Seed screened for low conversion of nicotine to nornicotine (sc) and high converter (HC) selections of TR Madole dark tobacco were cured in barns near Princeton and Lexington, Kentucky in 2012 and 2013. Temperature and relative humidity were measured with data loggers placed at 27 locations within each barn for the duration of curing. TSNA content was determined from 20-leaf samples collected from each selection at each of the 27 locations within each barn. There were no significant effects of individual data logger placement in either variety selection on hours above 24°C temperature, hours above 80% relative humidity, or TSNA; therefore, we investigated these data within 3-dimensional aspects of tier, room, and bent within each barn. There were various effects of tier, room, and bent on temperature, relative humidity, and TSNA; but limited significant relationships between temperature, relative humidity, and TSNA.