Potassium nitrate (the main ingredient of gunpowder) has historically been used as a preservative, particularly for curing meat. Some people might still use it, but these days sodium nitrite is more common.

It's just occurred to me that humans likely found out that KNO3 acted as a preservative/curing agent when gunpowder got accidentally mixed with food provisions. I can imagine on board some old war galleon or with army materiel that gunpowder accidentally spilt on foodstuffs and someone discovered its preserving properties.

Does anyone know if this happened (it seems a plausible idea to me)?

It’s what gives certain meats looked corned beef that distinct “pink” color.

KNO3 and nitrites are still used to cure meats, in salami etc. The argument these days is that nitrates/nitrites used for such purposes are potentially carcinogenic.

>KNO3 and nitrites are still used to cure meats, in salami etc.

What? That's absurd. Food processors would never do such a thing. They only use the finest cultured celery powder (filled with "all natural" sodium nitrite).

Makes sense, in fact it seems the ingredients are all still individually in use as food additives, if rarely.