The invention pertains to a method, a system and a component for systematically and automatically controlling a product, whose preservation in a distribution circuit depends on temperature, in particular a product subjected to a cold chain. The method includes: affixing, on the product, a marker including elements, in particular the bars of a bar code, intended to be identified by automatic processing units, fixing a component on the product. The component includes at least one part including a mask intended for masking the elements of the marker, at least temporarily, without modifying them, when (i) the temperature of the product exceeds a specific temperature threshold or (ii) when the preservation conditions differ from a specific reference level, in particular characterized by the exceeding of a specific temperature threshold for a longer duration than a specific duration or by the exceeding of a specific preservation duration.