7 Pa. Code § 59a.339
The product contact surfaces of dump hoppers, screens and mixers which are used in the process of transferring dry products from bulk containers to fillers for small packages or containers must be of stainless steel or equally corrosion resistant material and designed to prevent contamination. Parts must be accessible for cleaning. The dump hoppers must be of a height above floor level to prevent foreign material or spilled product from entering the hopper.
This section cited in 7 Pa. Code § 59a.326 (relating to equipment and utensils).