Although FDA issued some regulations prior to 1938, their legal status and enforceability were frequently challenged. The express rulemaking authority of the 1938 Act, however, began to alter industry's attitude toward and acceptance of the agency's regulations, although the substantive character of the regulations continued to be challenged from time to time (Pfeifer, 1984). Passage of the Administrative Procedure Act in 1946 established the basic framework of rulemaking for all government agencies, including FDA (Mintz and Miller, 1991). The agency, however, did not immediately turn to rulemaking as its principal means of setting implementation policy under FDCA. Thus, by the early 1970s, FDA and many other Federal agencies were subjected to criticism by the Administrative Conference of the United States for not establishing policies through rulemaking (Hamilton, 1972). In response to that criticism, agencies began to expand their use of regulations as a means of enunciating policy.

During this same period, new and innovative approaches to regulate food labeling were being proposed. Many recommendations from the final report of the White House Conference on Food, Nutrition, and Health (WHC, 1969) formed the basis for FDA's proposing new regulations on nutrient content labeling and alternative regulatory approaches for other aspects of food labeling (i.e., the common or usual name regulation instead of the establishment of standards of identity; 21 CFR Part 102; FDA, 1972; FDA, 1973).

The promulgation of rules has now become the principal means by which FDA implements its regulatory programs. During the past two decades, its regulations have become increasingly detailed in their requirements and the preambles to the regulations have become more extensive in their discussion of the agency's rationale and plans for enforcement. Regulations are now used to set standards for or otherwise define products, require specific labeling, establish procedures or define good manufacturing practices for the industry, or establish administrative processes for use by the public or the agency itself (Pfeifer, 1984). FDA's rationale in part is that by publicly establishing rules, responsible firms will comply, thus contributing to efficient enforcement of FDCA (Hutt and Merrill, 1991).

The process of promulgating regulations is burdensome and time-consuming. Therefore, regulations ordinarily speak to matters that are not transient or subject to frequent change. To address matters that are of