Section 53.5 - Disinfection or destruction of materials(a) In order to prevent the spread of disease, materials contaminated by or exposed to disease shall be disinfected: Provided, however, That in all cases in which the cost of disinfection would exceed the value of the materials or disinfection would be impracticable for any reason, the materials shall be destroyed, after appraisal as provided in § 53.3 .(b) The disinfection or destruction of materials under this section shall be under the supervision of an APHIS employee who shall prepare and transmit to the Administrator a certificate identifying all materials which are destroyed, showing the disposition thereof.28 FR 5935, June 13, 1963, as amended at 56 FR 51974, Oct. 17, 1991