Among the processors of PDO "Queijo de Nisa" two different types of cheese dairies were identified : one type including micro and artisanal units and the other type including small firms with industrial equipment. This contribution tries to answer the question "For what reasons is cheese without typicity produced by the units with industrial equipment ?". The action associates the local managers of PDO and researchers, including the authors of this paper, and the conclusion presented results from a joint reflection on the scope of an action - research model. It is adopted the point of view of plurality of rationality in management actions in the field of Protected Designation of Origin.