Foreign animal casings imported into the United States without certification may be forwarded in customs custody to a USDA-approved facility for disinfection under APHIS supervision and release by the United States Customs authorities, provided that, before being transported over land in the United States, each and every container of such casings shall be disinfected by the application of a solution of sodium hydroxide prepared as follows:

Sodium hydroxide (Lye) prepared in a fresh solution in the proportion of not less than 1 pound avoirdupois of sodium hydroxide of not less than 95 percent purity to 6 gallons of water, or one 131/2-ounce can to 5 gallons of water. 2

2 Due to the extreme caustic nature of sodium hydroxide solution, and of sodium carbonate solution to a lesser degree, precautionary measures such as the wearing of rubber gloves, boots, raincoat and goggles should be observed. An acid solution such as vinegar shall be kept readily available in case any of the sodium hydroxide solution should come in contact with the body.

This solution shall be thoroughly applied to all exterior surfaces of the containers and be allowed to remain for at least thirty minutes to accomplish disinfection. The containers should then be washed with water to remove the caustic soda which otherwise might cause injury to the handlers of the packages.

When uncertified foreign casings are removed from the original shipping containers these containers shall be destroyed by burning or promptly and thoroughly disinfected both inside and out with the solution and in the manner above prescribed. If these containers are to be re-used it is important that they be thoroughly washed both inside and out with water after disinfection has been completed, and in order to insure against the injurious effect of caustic soda remaining in the wood it is advisable to allow the containers to stand for not less than six hours filled with water.

The salt removed from all original shipping containers of uncertified foreign animal casings shall be immediately dissolved in water and heated to boiling, or disposed of as provided in paragraph (c)(1) or (2) of this section as follows:

Dissolve the salt in the proportion of 90 pounds of salt to 100 gallons of water. Add 23/4 gallons of C. P. hydrochloric acid containing not less than 35 percent actual HCl; mix thoroughly and allow the solution to stand for at least thirty minutes. The finished solution must contain not less than 1 percent actual hydrochloric acid. (This solution may be utilized in the disinfection of casings as prescribed in § 96.13.)

Dissolve the salt in the proportion of 90 pounds of salt to 100 gallons of water. Add 20 pounds of 95 percent to 98 percent sodium hydroxide (commercial “76 percent caustic soda”) and stir until solution is complete; and allow it to stand for at least 30 minutes. (This solution may be utilized in the disinfection of casing containers as prescribed in paragraphs (a)(2) and (b) of this section.

It is best to employ flaked caustic soda and not the variety which is very finely powdered. The fine powder is irritating and injurious to workers if it becomes suspended in the air. Containers of caustic soda should be kept tightly closed as the product deteriorates from contact with the air.