Foreign animal casings offered for importation into the United States without certification may be disinfected, as prescribed in this section, under the supervision of an APHIS inspector for use as food containers, as an alternative for foreign certification.

(a) Disinfect the casings in a solution made as follows: Dissolve 90 pounds common salt in 100 gallons water and mix. Add 2 3/4 gallons (10.35 liters) C. P. hydrochloric acid containing not less than 35 percent actual HCl and mix thoroughly. The finished solution must contain not less than 1 percent actual hydrochloric acid.

(b) Containers of the disinfectant solution may be either of wood or of metal, but the interior surfaces must be protected by means of an acid resistant coating.

(c) Not more than 175 pounds casings shall be treated with each 100 gallons of the solution. After the treatment of 175 pounds of casings, or at the end of the day if less than 175 pounds of casings are disinfected in any one day, the solution shall be discarded unless means are provided for accurately determining the loss of strength. In event means for accurately determining loss of strength are provided it will be permissible to restore the strength of the solution with fresh acid and use it repeatedly.

(d) Shake as much of the adherent salt as possible from the casings and weigh them. Bundles must be separated but individual hanks need not be untied. Place the casings in the disinfecting solution a few hanks at a time with vigorous agitation to insure the fullest possible contact of the solution with them. Then keep the casings completely submerged in the solution for not less than three-fourths of an hour.

(e) Remove the casings from the solution, rinse them with water, and place them in a solution containing 8 1/2 pounds of sodium bicarbonate in each 100 gallons of water. 100 gallons of this solution is sufficient for 175 pounds of casings. Keep the casings in this solution for 30 minutes, moving them about frequently and vigorously so as to insure complete contact of the solution with the casings. After this neutralization, remove the casings from the sodium bicarbonate solution and wash them to remove the excess of bicarbonate.