Comparing the Accuracy of Three Odour Analysis Techniques Used in Europe, North America, Australia, New Zealand and Asia

There are currently several different methods for dynamic olfactometry analysis that are universally used. In Europe, Australia, New Zealand and North America, the Triangular Forced Choice Method, the Binary Forced Choice Method, and the Yes/No Choice Method are commonly used for dynamic olfactometry analysis. They are supported by the European Standard: EN13725: 2003, the USA ASTM E679-04: 2011 standard, and the Australian/ New Zealand AS/NZS4323: 2001 Standard. All of these methods use a decreasing dilution series designed to determine an odour detection threshold value. In China, Japan, and much of South East Asia, an increasing dilution series is used for odour evaluations that are described in the “Odor Index Regulation and Triangular Odor Bag Method” and the document: GB/T14675-93 guideline. The Triangular Forced Choice Method is believed to be statistically the most accurate method, however the downside of this method is the length of time it takes to perform analysis. The long analyses time may incur possible fatigue from panelists who are evaluating samples. Over time, this may result in less accurate results. Also, with this method, there are usually less samples analyzed per odour panel session or day. The objective of this paper is to conduct a comprehensive quantitative comparison of the three most commonly used methods for dynamic olfactometry odour analysis. The results obtained from this study are based on analysis using the same type of olfactometer and the same group of panelists, in order to minimize any deviation caused by other factors than the test methods. This study compared a decreasing dilution series to the increasing dilution series methods. A modified Japanese method was used for this study where standard Triangular Forced Choice Method was conducted in the increasing dilution series.