Chemical or physical analyses are not sufficient to judge the quality of a product, but nor is tasting.
The origin of the product must be understood (In which area did it originate: in the mountains or plains? In an urban or isolated zone? In a humid or arid climate? In a well-defined or vast area?). The communities must be consulted (Is the product known by everyone or by a small number of people? Is it considered a high-value product, destined for festivals and ceremonies, or a poor-man's food?). Processing techniques must be understood (Is it a raw or pasteurized milk cheese? Is the curd cooked, uncooked stretched? Is the cheese fresh or aged?), as well as conservation methods (Is it smoked, wrapped in straw, etc?)
Then of course, we taste to evaluate organoleptic aspects. A product is interesting if it is complex, meaning if it evolves in the mouth, offering perceptions that change and last. A dull product will offer brief perceptions and finish on the nose and palate as it began, with the same characteristics. Tasting can identify potential defects (notes of rancidity, excessive acidity, etc.), identify the main organoleptic characteristics (aroma, taste, consistency), understand if there is equilibrium and harmony between the various taste and smell components, and if the product expresses its territory and typology well. At times an element that seems a defect is actually typical for that area, for the local tastes or for the typology. For example, bitterness in goat's cheese is a defect, but it is a typical characteristic of some alpine cow's cheeses.
In summary, Slow Food's definition of the quality of a food product is a story.