Taking as its point of departure the falsification of wine in France between 1871 and 1914, the article analyses the origins of such modern notions as "natural product", "branding", and "quality" with regard to food. With the development of synthetic chemistry, it is the very definition of an agricultural product that is in crisis; a wine can now be entirely factory-made. The interest in the well-being of the consumer and the modern forms of state intervention in the economy have grown in response to this phenomenon. The article nevertheless shows how, in fact, public healthcare remains subordinate to the objective of guaranteeing "loyal" relations between producers and merchants. The search for an institutional definition of wine permits the exclusion of certain practices and thus excludes a margin of the competitors on the market. It is for this reason that the economic and legal role of the expertise is so important. Such expertise acts simultaneously as an instrument of legitimisation of decisions adopted and as a coordinator between economic players. The recourse to expertise nevertheless modifies the balance in the relationship between legislative, juridical and executive power, to the advantage of the last one mentioned in this list.