CORESTA Sub-Group TSNA in Air-Cured and Fire-Cured Tobacco
(Established as TSNA Task Force in 2002)

Chair:  Andy Bailey, University of Kentucky

6 original objectives with subcommittees assigned to address each objective

Objectives:

1)  Create survey of critical farmer practices

       Subcommittee Chair:  George Scott, Universal Leaf

       Objective 1 status:  completed

Survey submitted to Scientific Commission

2)  Conduct collaborative study to investigate standard deviation of moisture content of    marketing packages

       Subcommittee Chair: 

       Objective 2 status:  dropped

Initial moisture content of marketing package not as important as storage      environment of marketing package.

3)  Develop standardized nornicotine screening protocol so that baseline levels of nornicotine are comparable in tobacco seed varieties used by investigators

Subcommittee Chair:  Anne Jack, University of Kentucky

Objective 3 status:  completed

Agreed that Univ. of KY screening protocol could be used without adding "LC" to variety name, provided that acknowledge was made that this protocol was used.  If "LC" is added to name, Univ. of KY protocol must be used.

4)  Develop a collaborative study which uses HOBO data loggers or similar instrumentation to collect curing conditions and possible impact on TSNA levels for tobaccos of diverse origins and curing environments.  Attempt to standardize placement of equipment.

Subcommittee Chair:  vacant

Objective 4 status:  completed

Cooperative study conducted in 2008 and 2009 by Virginia Tech and University of Tennessee (coordinated by Danny Peek, Virginia Tech).  Study directly compared the influence of growing and curing environments and compared environmental data from HOBO meters placed on tier rails between tobacco and within tobacco during air-curing of burley.  Results of experiment indicated that growing environment Iin addition to curing environment) also impacts TSNA formation.  Results also suggested that at low temperatures during curing, relative humidity has lesser influence on TSNA.  Results also showed that when evaluating TSNA across many environments, there is too much variability to confirm that higher relative humidity and higher temperature always results in higher TSNA.

Collaborative experiment did not directly compare placement of metering equipment.  However, it is the opinion of the TSNA subgroup that:

• At least 1 meter should be placed in the top and bottom tiers of barn
• When tobacco is not all housed in the barn at the same time, meters should be placed in tobacco at each time of housing
• Meters should be placed within the tobacco, hung from the center of stick at same level on plant where sample will be collected
• Meters should be calibrated each year ideally to ensure accuracy (particularly RH)

5)  Develop protocol for sample collection and handling of post-cure tobacco for TSNA analysis

Subcommittee Chair:  Marlene Adams, R.J. Reynolds Tobacco Co.

Objective 5 status:  Protocol near completion after re-evaluation

Parameters suggested for sampling protocol:

• Moisture content at sampling should be <18% for burley, 20-25% for dark tobacco.
• Number of leaves per sample for plant sampling should be 30 leaves per sample from 30 different plants, or as many leaves as possible, with no leaves collected from outside plants on stick.  Leaves sampled should be the 4th leaf from the top of each plant, with the same leaf sampled within each study. 
• For bale sampling, suggest 2 samples of at least 0.7 kg per sample from each 25 kg bale.
• Whole leaf or lamina only can be used for analysis, as long as a homogeneous ground sample is analyzed. Separation of lamina and midrib suggested for burley, may not be separated for dark and oriental.
• Freeze drying of sample recommended, or air drying with low humidity/dehumidifier.
• Maximum temperatures for air drying samples should be no more than 30 C.
• Minimum temperature for storing ground samples need not be lower than -18 C.
• At -18 C, storage time for ground samples is not critical.  At temperatures higher than -18 C, sample storage time should be as short as possible.

6)  Review issues of post-cured storage and ventilation parameters.

Subcommittee Chair:  Lowell Bush, University of Kentucky

Objective 6 status:  Review and report completed