As odor produced by livestock production systems became an increasing concern of the public and resulted in many complaints, the need to determined odor threshold concentration with reliable and rapid methods has also increased. As malodorous compounds from livestock production are numerous and complex to analyze, olfactometry is still the best method to scale the human sensory response to odor. A new automated triangular forced-choice olfactometer was developed according to ASTM Standard and evaluated. This olfactometer features 15 dilution levels and testing of most odor samples can completed in less then 10 minutes by 4 panelists. To obtained accurate results with olfactometry, it is important to give enough attention to panel selection and training, to selection of sampling bags, to the storage of the samples and to the calibration of the olfactometer. Testing on sampling bag showed that Tedlar bags are more reliable than PVC bags due to the lowest permeability of Tedlar and that samples in those bags can be stored to up to a week with little changes in the results. If the odor analysis are done within a few hours (less than 4) polyethylene bags, which less expensive, can be used.

The testing of the sample bags is interesting because it gives more information about the aging of the sample and help choosing the best sample bags according to the delay before sampling analysis. For the olfactometer, some descriptions are given but they are very brief.