Reliability of subjective odor quantification using the refined cloth swatch olfactometric technique

The cloth swatch olfactometric technique uses cloth flannel swatches to absorb odors for presentation to a trained human sensory panel. This study examined the reliability of the refined cloth swatch technique used to facilitate the subjective quantification of odor intensity and offensiveness of swine facility wastewater treated in subsurface-flow constructed wetlands. Reliability was based on the consistency of ratings assigned by panelists to odor sample replicate pairs. Seven out of eight panelists assigned the same or slightly different odor intensity and offensiveness level ratings for at least 75 percent of the trials. Two panelists were 100 percent consistent throughout all trials. The distribution of the differences between odor ratings assigned to replicate pairs indicated those differences of ±0 and ±1 accounted for approximately 80 percent of the total odor tests. The right-skewed distribution of odor intensity and offensiveness level differences indicated that the human sensory panel used consistent judging criteria. .The cloth swatch olfactometric technique used by human sensory panelists yielded highly consistent results indicating that odor intensity and offensiveness level rating data obtained using the refined cloth swatch technique was reliable to use for various odor analyses.