The manufacturer of Tuff Cloth answered this question in a similar thread some months ago.
Tuff Cloth is not approved for use in food service because obtaining those approvals is expensive and the market is very small. Also, the application method, a cloth that is used again and again, isn't overly sanitary for food service. But, there's nothing in Tuff Cloth that's poisonous or anything. If you're engaged in professional food service, it's probably best not to use Tuff Cloth since it isn't legally approved. But, for your own use, it's fine.
Chuck