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Formation and Reduction of Tobacco-specific N-nitrosamines (TSNA) in Dark Tobaccos
W. A. Bailey
Department of Plant and Soil Sciences
Tobacco specific N-Nitrosamines (TSNA) are carcinogenic substances that have been identified in tobacco products. This project evaluates current levels of TSNA in dark tobaccos as well as the effects of common dark tobacco production practices such as nitrogen fertility, topping, harvesting, and housing methods on TSNA formation. This project also evaluates the effect of preharvest antioxidant applications on TSNA formation in dark tobacco.
2009 Project Description
EXPERIMENTS: Four field experiments were conducted in 2009 to address the formation of TSNA in dark fire-cured tobacco. One experiment addressed the effect of preharvest applications of ferulic acid (known antioxidant) in combination with different alcohols on TSNA levels in dark fire-cured tobacco. Another experiment that was conducted at 2 locations involved the use of ethephon as a yellowing/ripening agent applied to dark tobacco prior to harvest in an effort to reduce the amount of time for possible bacterial and resulting TSNA accumulation between tobacco housing and first firing in the curing barn. A third experiment involved evaluation of 'pale yellow' dark tobacco genotypes that genetically begin to yellow in the field prior to harvest, possibly also allowing a reduction in the amount of time between tobacco housing and first firing to possibly reduce bacterial growth and possible TSNA accumulation.
EVENTS: Two field days were conducted in 2009 (Princeton, KY and Springfield, TN) that included topics related to TSNA formation in tobacco and information was presented from project experiments. Three grower meetings that specifically addressed TSNA formation in dark tobaccos from information obtained from this project were also conducted in 2009. Two extension agent trainings (1 for Kentucky agents and 1 for Tennessee agents) were also conducted in 2009 and addressed TSNA formation in dark tobaccos and included information obtained from this project. One additional training that addressed TSNA formation was also held specifically for industry representatives. One professional scientific meeting was attended in 2009 where information was presented from data collected from this project.
Results and dissemination of information from this project thus far has resulted in a change in the level of knowledge for growers and industry representatives, and changes in action relating to dark tobacco marketing periods and storage has occurred for the industry. Changes in grower production practices regarding seed selection, nitrogen use patterns, housing density, fire-curing methods and market preparation continued in 2009. Dark tobacco buying companies continue to use information from this project in their buying decisions as well as for use in their own educational programs for growers.
Bailey, A. 2009. Report on activities of CORESTA subgroup TSNA in air-cured and fire-cured tobacco. Proceedings of 2009 Meeting of CORESTA Agro-Phyto Group, October 3-5, 2009, Rovinj, Croatia.
A. Bailey. 2009. Two cures instead of one. Southeast Farm Press (in press).