The article presented here is rooted in our doctoral research in Ethnology and Social History developed in the lagoon of Venice in 2010-2013. It is a research based on the methodology of ethnographic field research, in parallel with the bibliographic and archive research. The fieldwork was conducted between March 2010 and August 2012 with 21 informants, fishermen aged 20 to 90 years. In this article we analyze how the formation of a new food taste is a process that can be defined “cultural”. We can meet an example in the history of mussel-farming on the island of Pellestrina, an island of fishermen in the southern lagoon of Venice, where the exploitation of this mollusk as food and economic resource appears rather late in history. Our research enabled us to find some frequent allusions to the alleged toxicity of this mollusk, called in Venice peòcio, that is to say “louse”, and once considered inedible. What mechanisms have transformed today the mussels into an appreciated and great demanded food, into “traditional food”?