(a) Carcasses, parts thereof, meat and meat food products (other than rendered animal fats) that have been treated in accordance with the provisions of this subdivision shall be considered denatured for the purposes of the regulations in this Part, except as otherwise provided in Part 314 of this Title for articles condemned at official establishments.

1. (1) The following agents are prescribed for denaturing carcasses, parts thereof, meat or meat food products which are affected with any condition that would result in their condemnation and disposal under Part 314 of this Title if they were at an official establishment: crude carbolic acid; cresylic disinfectant, a formula consisting of one part FD&C green no. 3 coloring, 40 parts water, 40 parts liquid detergent and 40 parts oil of citronella, or other proprietary substance approved by the commissioner in specific cases.
2. (2) Except as provided in paragraph (3), (4) and (5) of this subdivision, the following agents are prescribed for denaturing other carcasses, parts thereof, meat and meat food products, for which denaturing is required by this Part: FD&C green no. 3 coloring; FD&C blue no. 1 coloring; FD&C blue no. 2 coloring; FD&C violet no. 1 coloring; finely powdered charcoal; or other proprietary substance approved by the commissioner in specific cases.
3. (3) Tripe may be denatured by dipping it in a six percent solution of tannic acid for one minute followed by immersion in a water bath, then immersing it for one minute in a solution of.022 percent FD&C yellow no. 5 coloring;
4. (4) Meat may be denatured by dipping it in a solution of.0625 percent tannic acid, followed by immersion in a water bath, then dipping it in a solution of.0625 percent ferric acid; and
5. (5) When meat, meat by-products, or meat food products are in ground form, four percent weight of coarsely ground hard bone, which shall be in pieces no smaller than the opening size specified for no. 5 mesh in the standards issued by the United States Bureau of Standards or six percent by weight of coarsely ground hard bone, which shall be in pieces no smaller than the opening size specified for no. 8 mesh in said standards, uniformly incorporated with the product may be used in lieu of the agents prescribed in paragraph (2) of this subdivision.
6. (6) Before the denaturing agents are applied to articles in pieces more than four inches in any dimension, the pieces shall be freely slashed or sectioned. (If the articles are in pieces not more than four inches in any dimension, slashing or sectioning will not be necessary). The application of any of the denaturing agents listed in paragraph (1) or (2) of this subdivision to the outer surface of molds or blocks of boneless meat, meat by-products, or meat food products shall not be adequate. The denaturing agent must be mixed intimately with all of the material to be denatured, and must be applied in such quantity and manner that it cannot easily and readily be removed by washing or soaking. A sufficient amount of the appropriate agent shall be used to give the material a distinctive color, odor, or taste so that such material cannot be confused with an article of human food.