This is not always the case, see https://www.quechoisir.org/actualite-jambon-cuit-que-valent-les-jambons-sans-conservateurs-n44900/ https://www.quechoisir.org/a

This is not always the case, see https://www.quechoisir.org/actualite-jambon-cuit-que-valent-les-jambons-sans-conservateurs-n44900/ https://www.quechoisir.org/actualite-jambon-cuit-que-valent-... (in French). Summary: a test of no-nitrate ham confirmed the claim. The test is done by one of the best known consumers magazine.