7 Pa. Code § 59a.336
Newly installed sifters used for dry milk and dry milk products must meet the current 3-A Sanitary Standards for Sifters for Dry Products. Other sifters must be constructed of stainless steel or other equally noncorrosive material and must be of sanitary construction and accessible for cleaning and inspection. The mesh size of sifter screen used for various dry dairy products must be those recommended in the appendix of the referenced 3-A Sanitary Standard.
This section cited in 7 Pa. Code § 59a.326 (relating to equipment and utensils).