Here's the draft guidance on the topic from 2016............and since this popped up first on google, guessing the FINAL has not yet been published
https://www.fda.gov/...y/UCM499201.pdf
C. Labeling (§ 507.28(b)) When the human food by-products for use as animal food are distributed, labeling that identifies the product by the common or usual name must be affixed to or accompany it. (§ 507.28(b)). Labeling could be included on the invoice or bill of lading, for example. Our Compliance Policy Guide Sec. 665.100 discusses common or usual names for animal food ingredients, including the use of the ingredient definitions in the AAFCO Official Publication. 6 There are also industry and other regulatory resources that may assist facilities in determining the common or usual name of the animal food, such as the foods listed in the USDA National Nutrient Database for Standard Reference.
7 D. Shipping containers and bulk vehicles (§ 507.28©) When the facility is responsible for transporting the human food by-products for use as animal food itself or arranges with a third-party to transport the animal food, the shipping containers (for example, totes, drums, and tubs) and bulk vehicles used to distribute the animal food must be examined prior to use to protect against the contamination of animal food from the container or vehicle. (§ 507.28©). When the facility is the shipper, we expect facility personnel involved in the process of loading the product into the shipping container or vehicle to be aware of the condition of the shipping container or vehicle, and consider whether its condition would contaminate the human food byproducts for use as animal food. Depending on the circumstances, this examination could include looking at the shipping container or vehicle to observe whether there are any residues in it that may contaminate the human food by-product for use as animal food. When a visual 6 FDA, Compliance Policy Guide 665.100 Common or Usual Names for Animal Feed Ingredients, http://www.fda.gov/I...l/ucm074687.htm. 7 USDA, National Nutrient Database for Standard Reference, http://ndb.nal.usda.gov/ Contains Nonbinding Recommendations Draft – Not for Implementation 10 inspection is not practical, we would expect the facility to know what the shipping container or vehicle had previously been used for and because of that, whether the container needed to be cleaned prior to use to protect the human food by-product for use as animal food from contamination. This does not mean that the shipping container must be cleaned prior to each use in all situations. The regulations do not require the facility to examine the shipping container or bulk vehicle when the customer arranges for the transportation of the animal food, including when the customer arranges for a third-party to pick up the animal food. However, if facility personnel are onsite and available, it would be good practice for the facility to examine the customer's shipping container or bulk vehicle to confirm that the shipping container or bulk vehicle will not lead to the contamination of the human food by-products for use as animal food.