I just came back from the shop in my village where they were selling bacon made on the local farm. Having recently read this article I checked the ingredients:

I just came back from the shop in my village where they were selling bacon made on the local farm. Having recently read this article I checked the ingredients: Preservatives (E250, E252). A quick search told me that E250 is Sodium nitrite, and 252 is potassium nitrate (saltpetre). Apparently the whole range 240-259 is for nitrates.