7 Pa. Code § 1.544
(b) When such restricted product is shipped from one official establishment to another official establishment in the same railroad car or other means of conveyance with other product, such restricted product shall be packed in individual closed containers and the containers shall be sealed in accordance with § 1.333(g) (relating to treatment by refrigerating), and marked “Pa. passed for cooking” or “pork product
degrees F. days refrigeration” or “beef passed for refrigeration,” as the case may be. In addition, a “Pa. Retained” tag shall be securely affixed to each container of product passed for cooking and of beef passed for refrigeration. The means of conveyance shall not be sealed unless at least 25% of the other product in the vehicle is unmarked.
This section cited in 7 Pa. Code § 1.141 (relating to general requirements); and 7 Pa. Code § 1.231 (relating to marking of outside containers—general).