GB/T 39558-2020

This standard specifies the "A"-"not A" test methodology for sensory analysis, used to determine whether a perceptible difference exists between two products, particularly when one is a known reference (A) and the other is a variant or unknown sample. It is applied in the food industry for quality control, product development, and shelf-life testing, such as evaluating subtle changes in flavor, texture, or aroma between a standard product and a modified version. The method is also relevant in contexts like packaging material assessment or ingredient substitution where a trained panel must identify deviations from a fixed reference.