Is Finished Article Testing Required When No End Test is Specified?
When an end test is not required for a specific polymer (i.e., polypropylene, polyethylene, olefin) in a food-contact article (i.e., 21 CFR 177.1520), could a manufacturer considers this article as FDA APPROVED without tests on the finished article? Or, must the finished article always be tested? If testing is required, where are the established test conditions?
First, please note that the U.S. Food and Drug Administration (FDA) has stated that it "objects strongly" to the phrase "Approved by FDA" in connection with the marketing or labeling of a product that has been processed through the food additives regulations (see Compliance Policy Guide (CPG) Section 500.300). Rather, a firm may state that it is selling a regulated food additive, or that a substance is either in compliance with the food additive provisions of the Federal Food, Drug, and Cosmetic Act or is cleared by FDA for its intended use.
The answer to your first two questions would depend on the specific polymer, the overall composition of the finished food-contact article, and—in some cases—the intended conditions of use. In general, the "mixture doctrine," permits manufacturers to physically blend substances that are separately cleared by FDA for the intended use. Under this doctrine, such blends require no further FDA clearance provided that each substance in the mixture complies with any limitations applicable to the substance in its respective regulation, and that no chemical reactions occur between the combined substances.
It is important to note that any limitations (i.e., extractives limitations) relating to the individual components of a mixture are properly applied to the relevant individual components rather than to the mixture. However, limitations relating to end-use application of the mixture (i.e., food-type or temperature limitations, or extractable limitations on the finished food-contact article), must be applied to the mixture as a whole. Additionally, the mixture is subject to the most restrictive end-use limitations applicable to any of the components.
In the case of olefin polymers, Title 21 of the Code of Federal Regulations (C.F.R.) Section 177.1520(f) specifically states that "olefin polymers identified in and complying with this section, when used as components of the food-contact surface of any article that is the subject of a regulation in parts 174, 175, 176, 177, 178, and Sec. 179.45 of this chapter, shall comply with any specifications and limitations prescribed by such regulation for the article in the finished form in which it is to contact food." The regulations on carboxyl modified polyethylene resins includes end-test requirements that must be conducted under the conditions of time and temperature characterizing the conditions of their intended use (see 12 C.F.R. 177.160(b)).
You also asked about where to find established test conditions. If a substance is specifically listed in a food additive regulation and testing is needed to determine compliance with the regulation, the compliance testing must be performed strictly as set forth in the regulation. For example, the analytical methods for determining whether olefin polymers conform to the required specifications are found in section 177.1520(d). The regulation on carboxyl modified polyethylene resins specifies that the total extractives of the finished food-contact article should be determined by the analytical methods described in section 176.170(d). Although section 176.170 is a regulation pertaining only to paper and paperboard food packaging, it is often referenced in other regulations, with respect to analytical testing.
Finally, even if a polymer is listed in part 177 and complies with all applicable specifications and limitations, the good manufacturing practices (GMP) requirements applicable to food-contact materials (found in Section 174.5) state that all packaging materials must be "of a purity suitable for [their] intended use." This "suitable purity" requirement means that any unavoidable residues or impurities that may migrate to food must be present at such low levels as to not render the food adulterated (i.e., harmful to human health or having an off taste or odor). Please consult legal counsel to determine your specific legal obligations.