Mytilus edulis galloprovincialis
Bivalve molluscs, In Italy are practically available everywhere there are rocks and wrecks. Being filterers they proliferate very well also in polluted water, for this reason it is very important to purchase only from serious sellers or make yourself informed where they come from. The Italian law is very severe about, and defines two fishing areas: the areas A ( bacteriological pure) where the mussels ca be sold directly from and the areas B , where it is necessary a purification period in depuration plants.
It is possible to buy also frozen and canned, but we find that they lose their sea perfume, that is the essence of this food.
For cleansing they must be put into fresh and salted water for at least 2 hours, then you must brush the shells with a scourer without detergent and then “de-beard” (remove the byssal thread from). In many shops it is possible to buy them already de-bearded, and avoid this boring cooking step. The only point is to cook quickly. As soon as de-bearded they must be cooked within no more than 1 hour: otherwise they will die and it will not possible to open.
They must cooked for few time, anyway you like them the cooking time must be short (5 minutes) or they become rubbery, hard and insipid. Remove the broken and unopened molluscs. Preserve always the water used for cooking: it is excellent for many recipes: filter and use for cooking the pasta, for the fish broth or make it dense for the white sauces.