Mediterranean mussels (Mytilus galloprovincialis) are edible mussels known as "pidoči" or "pedoči" in the Slovenian Primorje region and "dagnje" in Dalmatia.
In nature, mussels live in the intertidal zone where they attach themselves to a solid object such as a wall, pier, column, buoy or anything else that offers suitable conditions for life. Mussels feed on plankton that they filter from the water.
Mussels cultivated at mussel farms live in highly controlled conditions. They are attached to a system of ropes and nets suspended from floats that are organised into neat mussel farming fields. The location for a mussel farm is carefully selected: it should be quite far from the shore in a very clean part of the sea with just the right sea currents. Because cultivated mussels are constantly submerged and therefore enjoy better living conditions, they are of much better quality than wild mussels. Farmed mussels also have more meat compared to wild mussels of the same size.
The edible, meaty part of the mussel is protected by two dark blue, inedible shells. On one end of the mussel there is a tuft of inedible fibres (byssal threads), which some cookbooks refer to as the beard or tail; the mussel uses these fibres to attach itself to a solid surface.
Mussels can be enjoyed the whole year round, although you will find that they are slightly emptier in late autumn and spring when it's time for reproduction.
The commercial size of mussels starts a 5 cm, while the optimum size is around 7 cm, regardless of how the mussels are going to be cooked. Obviously smaller mussels can also be used and will be very tasty as long as they are prepared correctly. The interesting thing is that the largest mussels don't necessarily contain the most meat. Smaller mussels can be cooked "buzara" style (with olive oil, wine, garlic, breadcrumbs and fresh herbs) or used in soups, salads and risottos, while larger mussels can be used for roasting, frying or grilling.
After they have been harvested, mussels should be stored in a refrigerator or other cold space (e.g. on the floor in the pantry, garage or bathroom – a cold surface of stone or ceramic) at a temperature of +4 to +6 °C. In these conditions, they can survive and thus remain suitable for consumption for 3 to 5 days. Mussels should never be stored in water; no matter how big the container, they would use all of the oxygen in the water within just a few hours and die. Only live mussels can be used for cooking; this is also why they shouldn't be stored in the freezer unless they have been thermally processed first.
The shells of live mussels are tightly closed or slightly open but close immediately if touched. If open shells fail to close even when you press harder on them, it means that the mussel inside is dead and should be discarded. Similarly, discard any mussel that fails to open when cooked.
The main prerequisite for preparing a healthy and tasty dish is to buy fresh, good quality mussels. They should be alive, well washed, with unbroken and clean shells free of mud, sand or any major plant cover. Smaller growths (barnacles, tube worms) and remains of byssal threads are not harmful.
In addition to the above, mussels should be clearly marked with the place of production, producer, veterinary number and date of production. If a seller can't produce a declaration for the mussels, it's best not to buy them. This way, you can be sure that you will always get fresh mussels that meet the veterinary and food standards.