importance to industry but specific to a class of product or reflective of current scientific procedure, FDA provides advisory opinions—statements of policy and interpretation of its position on such issues. FDA has formalized the procedure by regulation (21 CFR §10.85; FDA, 1979, FDA, 1981).

The first advisory opinions were issued during the early 1940s as excerpts from trade correspondence, generally known as Ta. However, after passage of the Administrative Procedure Act in 1946, such policy statements were required to be published in the Federal Register, and the TC system was discontinued (Levinson, c. 1952), although a number of TCs remain in effect today as advisory opinions [21 CFR §10.85(d)(2)]. The TC system was followed by a system called "Statements of Policy and Interpretation," which were published in the Federal Register and codified. (The remnants of this system can be found in 21 CFR Part 1, Subpart B.) In recent years, FDA increasingly has used general statements of policy in the form of advisory opinions (in response to industry requests) or guidelines developed on its own initiative to indicate its position in instances in which regulations are not appropriate. For example, FDA developed guidelines to provide guidance on conducting safety studies of new food additive products requiring premarket approval; this guidance (known as the Red Book ) must be revised continuously to reflect contemporary scientific methods and thus is not amenable to issuance as regulations. Another example is The Fish List, which defines more than 100 species of fish for labeling purposes. Such guidelines provide a "safe harbor" for industry, because they are binding on FDA until revoked. They are not binding on industry; nevertheless, if followed by a company, they provide assurance that the conduct of the company is acceptable to FDA. The preambles to regulations and formal notices published by FDA in the Federal Register also carry advisory opinion status. The advisory opinion process is defined in 21 CFR §10.85.

As part of their day-to-day activities, FDA officials frequently are asked to make speeches, write articles for publication, or informally discuss current agency activities at public meetings. Such statements are eagerly sought and provide valuable insights into emerging policies. Investigators and compliance officers also are often confronted with situations in which they must discuss their views on FDA policy.

Such advice must be accepted for what it is: an informal communication that represents the best judgment of an employee at a given point in time but that does not constitute an official FDA advisory opinion. Except in cases in which the written advice is provided and issued under the provisions