My set up is for electric BIAB (brew in a bag) so I use a false bottom. The problem is that I don't know if the stainless steel I use is food grade or not. Are there any great risks for my health? Should I replace it or not?
I've never heard of non-food-grade stainless steel. Some are more or less susceptible to corrosion than others, but as far as I know all stainless steels are food grade.
[...] stainless steel is a safe option when it comes to use with food and beverage, as there are no chemicals that can migrate into your food from these products.