ISO 10399:2017规定了确定两种产品样品之间是否存在可感知的感官差异或相似性的程序。该方法是一个强制选择程序。该方法适用于单个感觉属性或多个属性中是否存在差异。 该方法在统计上比三角测试（在ISO 4120中描述）效率低，但评估员更容易执行。 即使差异的性质是未知的（即，它既不确定样本之间的差异的大小也不确定方向，也没有任何关于差异的属性的指示），该方法是适用的。该方法只适用于产品相当均匀的情况。 该方法是有效的 a）确定 要么是可察觉的差异结果（双重三重测试差异），要么 当例如在配料，加工，包装，处理或储存方面发生改变时，不会导致可察觉的差异（相似性的双重三重测试），以及 b）挑选，培训和监督评估人员。 描述了两种形式的方法: - 恒定参考技术，当评估人员熟悉一种产品时（例如来自正常生产的样品）; - 平衡 - 参考技术，当一个产品不是比另一个更为熟悉时使用。

ISO 10399:2017 specifies a procedure for determining whether a perceptible sensory difference or similarity exists between samples of two products. The method is a forced-choice procedure. The method is applicable whether a difference exists in a single sensory attribute or in several attributes. The method is statistically less efficient than the triangle test (described in ISO 4120) but is easier to perform by the assessors. The method is applicable even when the nature of the difference is unknown (i.e. it determines neither the size nor the direction of difference between samples, nor is there any indication of the attribute(s) responsible for the difference). The method is applicable only if the products are fairly homogeneous. The method is effective for a) determining that either a perceptible difference results (duo-trio testing for difference), or a perceptible difference does not result (duo-trio testing for similarity) when, for example, a change is made in ingredients, processing, packaging, handling or storage, and b) for selecting, training and monitoring assessors. Two forms of the method are described: - the constant-reference technique, used when one product is familiar to the assessors (e.g. a sample from regular production); - the balanced-reference technique, used when one product is not more familiar than the other.