Stainless Steel
I saw this post and though its old I thought I'd respond anyway. Stainless steel is the primary material used in food, beverage and pharmeceutical applications that require tanks, piping or other product contact surfaces because it is very sanitary. It is easy to clean and does not leach any components into the product. It is extremely corrosion resistant (hence the name) and is not coated. It is polished to different grades. The higher the grade, the less pourous the surface is and the more sanitary it becomes. You can tell if your part has any ferrous metal in it by simply seeing if a magnet will attach. The downside is that it is relatively expensive and somewhat difficult to work without the proper tools.