Patent ID: 6895974

Claim:
A method for preparing cured Virginia tobacco that has a TSNA content below 2 ppm, based on the dry weight of cured tobacco, comprising the steps of: providing a barn with an air circulation device and a heat exchange unit; putting harvested green Virginia tobacco in the barn; producing heated air and nitric oxide gases through the act of burning a propane or diesel fuel in the heat exchange unit; preventing substantially all of the nitric oxide gases from contacting the harvested tobacco and from causing a chemical reaction therewith; circulating the heated air with the aid of the air circulation device, through the barn for at least about 120 hours in the absence of substantially all of the nitric oxide gases to produce cured tobacco while preventing formation of TSNA in the cured tobacco that would otherwise be formed by the chemical reaction; ascertaining the nitric oxide content in the barn while the heated air is being circulated there through: and determining that the TSNA content of the cured tobacco is below 2 ppm.