27 CFR § 5.66 - Comparative advertising.
(a) General. Comparative advertising shall not be disparaging of a competitor's product.
(b) Taste tests.
(1) Taste test results may be used in advertisements comparing competitors' products unless they are disparaging, deceptive, or likely to mislead the consumer.
(2) The taste test procedure used shall meet scientifically accepted procedures. An example of a scientifically accepted procedure is outlined in the Manual on Sensory Testing Methods, ASTM Special Technical Publication 434, published by the American Society for Testing and Materials, 1916 Race Street, Philadelphia, Pennsylvania 19103, ASTM, 1968, Library of Congress Catalog Card Number 68-15545.