'Salame d'oca', or goose salami, is a specialty of Lomellina, the Pavia Province area whose borders are marked by the Po, Ticino and Sesia rivers, and where goose raising is a very ancient activity, due the widespread availability of natural fresh water springs and the presence of abundant tender grasses. The city of Mortara, for which this peculiar sausage is named, is the historical and geographical centre of Lomellina. The 'salame d'oca' tradition is rooted in distant times. It is believed that goose salami was inspired, at least in part, by the numerous Jewish communities of Lomellina which, when Ludovico il Moro ruled the region, asked local sausage makers for goose salami and fried fat scraps, as a kosher alternative to pork products prohibited by their religion. There are several different theories regarding the origin of modern goose salami, which combines goose meat with pork. The most likely one is that non-Jewish clients found goose meat, by itself, insufficiently tasty, and the master sausage makers of Mortara decided to add pork to the recipe. This theory is supported by the authoritative opinion of the classic Italian cuisine master Pellegrino Artusi. In his 1891 treatise 'Science in the kitchen and the art of eating well', Artusi described the preparation of a similar goose sausage in Lomellina.

The wording 'Salame d'oca di Mortara' and 'Indicazione Geografica Protetta' must appear on the products' packaging. The product's unique logo, always side-by-side with the Protected Geographic Designation, must be on the label. The logo consists of an oval light-blue seal inside which are a green map of Lomellina, a white goose, the Abbey of St. Albino and two yellow rice spikes.