Olive Oil
Also known as extra virgin olive oil, Olivenöl, huile d'olive, olio d'oliva, aceite de oliva
Used in charcuterie mainly to exclude air rather than to season: the covering oil over a preserved product. It is liquid at cellar temperature, which is exactly why it must never be treated as a substitute for pork fat in a mix.
Olive oil appears in cured meat work in three quite different roles, and confusing them causes real problems.
The first and most important is as a covering medium. Preserved meats packed under oil, the Italian sott'olio preparations, tuna and other fish in oil, sausages stored submerged, and some fresh cheeses use the oil to exclude air from the product surface. That excludes oxygen and slows rancidity and mould, and it is a genuine preservation aid. It is also precisely why the practice carries a serious hazard, which the safety note below sets out.
The second is as a seasoning and surface treatment. A thin film of oil on a dried sausage before slicing, a rub before roasting, a marinade for a fresh sausage or a dressing for a cured meat salad. Here it is doing nothing structural.
The third is as a fat in a mix, and this is the one to be careful about. Olive oil is liquid at every temperature a curesmith works at. Pork back fat is solid and stays as discrete particles that give a salami its mosaic and its bite. Substituting a liquid oil for a solid fat does not give a leaner sausage; it gives one that cannot form a mosaic, that will leak oil under any warmth, and whose emulsion is far harder to hold. Where a traditional formula genuinely uses oil in the mix, as some Mediterranean fresh sausages do at low levels, it is a small addition for succulence and not a replacement for the fat phase.
Quality grades matter more for flavour than for function. Extra virgin is cold-pressed, carries the polyphenols that give both the peppery bitterness and a genuine antioxidant benefit, and has a low smoke point. Refined or pomace oil is neutral and cheap and is the sensible choice where the oil is a covering medium rather than a flavour. Using an expensive extra virgin as pack oil wastes both the money and the flavour, since the polyphenols degrade over storage anyway.