TECHNICAL ADVISOR'S REPORT TO THE FOOD, DRUG, AND COSMETIC PACKAGING MATERIALS COMMITTEE*

FDA's Use Conditions Classification Systems

December 6, 2002

Lester Borodinsky, Ph.D.

Ladies and Gentlemen:

It is a great pleasure for me to be with you once again in the role of the Committee's Technical Advisor. This report will describe one of the current technical issues we are dealing with in establishing satisfactory regulatory positions for plastic food-contact materials. Specifically, there is often a need to establish compliance of components of food-contact articles on the basis of the conditions under which the articles will be in contact with food. The difference between one use condition and another may be critical, because different use conditions usually have different testing requirements and limitations on the condition of use may have an impact on how, or even with which foods, the packaging material can be used. While the Food and Drug Administration (FDA) has set forth definitions of conditions of use and stipulated their specific testing requirements, the definitions of the conditions of use are very general and often lead to more questions than answers. Since the ways in which FDA has related actual use conditions to generalizations for conditions of use varies from situation to situation, case-by-case considerations usually are needed when interpreting regulatory clearances with regard to conditions of use. The purpose of this report is to highlight some of the more confusing aspects of FDA's conditions of use and to provide some concepts to consider when categorizing actual use conditions.

As you all realize, all actual use conditions are not identical - usually, the conditions needed for packing food or processing packaged foods are dependent on the foods being packaged and the demands of the time and temperature needed to develop a sterile (enough) environment for the packaged food. Not only do these different processing conditions permit the food to be conditioned properly, they also enable the food to exert differing extractive capabilities with regard to components of food-contact materials because of the differing temperatures and lengths of time. As you know, because of these differences in extractive capabilities, the Food and Drug Administration (FDA) has developed its compliance stratagem for many food-contact substances to account for the difference in potential extractability due to the difference in the time and temperature. However, the Agency has recognized that it would be impractical to impose limits on specific foods or applications (although FDA has, on occasion, employed such limitations) and, instead, relies on general groupings of conditions of use that seem to be the most commonly encountered in actual use. This report will examine the food classification systems employed by FDA.

FDA'S USE CONDITIONS CLASSIFICATION SYSTEMS

FDA has developed several different classification schemes for use conditions. Although these varying classifications are used by FDA for diverse reasons, they are all useful for consideration here since they each shed light on how FDA has used and continues to use different systems under different circumstances. It is critical to recognize that the appropriate use condition system to employ may vary from situation to situation; the specific requirements for each situation will be dictated by the language of the regulatory clearance. Some examples of regulatory language will be considered later on; first, a review of the FDA use condition classification systems.1

Conditions of Use Enumerated in 21 C.F.R. § 176.170

Section 176.170 lists the components that FDA has cleared for use in the manufacture of paper and paperboard in contact with aqueous and fatty foods. Although this regulation is not directly relevant for most substances used as components of other types of food packaging, many of FDA's regulations for indirect food additives or Food Contact Notifications (FCN) for food-contact substances refer to Table 2 in Section 176.170(c), which enumerates eight Conditions of Use.2

The reason that the agency continues to cross-reference this tabulation of Conditions of Use is that FDA finds it more convenient to refer to an established reference consistently rather than to create a set of use conditions limitations each time a new food additive listing is promulgated or an FCN is allowed to become effective. It is important to recognize that the main purpose of Table 2 of Section 176.170(c) is not actually to define use conditions but rather to set forth compliance testing conditions for paper food-contact articles when used under varied conditions of use. In addition, while not directly related to Conditions of Use classifications, below is FDA's companion Table 1 in 176.170(c), a table that sets forth a system for categorizing different types of food, again by groupings.

As can be seen from the Conditions of Use classification in Section 176.170(c), Table 2, the Conditions of Use are arrayed essentially in a hierarchy of conditions from the most severe, Condition of Use A to the least severe, Condition of Use G; the exception to the absolute hierarchy is Condition of Use H, which is a more severe use condition than its immediate predecessor, Condition of Use G.

Conditions of Use Described in Other Clearances

While the Conditions of Use in Table 2 of Section 176.170(c) are the most commonly referenced use conditions, there are other ways in which FDA has limited use conditions. For example, Section 177.1520 ("Olefin polymers"), delimits the use of polyethylene and olefin copolymers on the basis of whether or not the polymers can be used in "articles used for packing or holding food during cooking;" neither this regulation nor others define the term "cooking."

In other instances, more specific limitations are emplaced. For example, Section 177.1312 ("Ethylene-carbon monoxide copolymers") limits the subject polymers to use "as food-contact materials at temperatures not to exceed 121°C (250°F)." Another example is the limitation on the use of nylon 6/12 under Section 177.1395 ("Laminate structures for use at temperature between 120°F and 250°F"), which permits the resin only for use with nonalcoholic foods at temperature not to exceed 100°C (212°F)." In addition, another example of a use condition that does not fit either the Conditions of Use A through H convention or reference to a specific temperature of use may be found in Section 176.170 - "Petroleum alicyclic hydrocarbon resins, or the hydrogenated product thereof" may be used in the bulk packaging of inter alia iced meat, fish, and poultry.

Yet another "unusual" condition of use is one of the limitations for a substance cleared via the threshold of regulation (Section 170.39 ("Threshold of regulation for substances used in food-contact articles").3 Specifically, threshold of regulation "file" number 99-020 permits the identified colorants under "(1) Conditions of Use F and G; (Table 2, 21 CFR 176.170) and (2) Condition of Use E for storage times of one hour or less."

Thus, FDA has employed different descriptions of use conditions for regulatory purposes without a consolidated way of aligning the different systems with each other. This lack of overlap is most noticeable when considering the Conditions of Use set forth in Section 176.170(c), Table 2 in conjunction with the cooking/non-cooking distinction for polyolefins in Section 177.1520. For example, a question may arise regarding how to properly characterize the permitted use of a mixture of a polyolefin and an additive, where the polyolefin has the limitation of "non-cooking" and the additive has a Condition of Use C limitation - which of these two limitations is more restrictive? Because of such "discrepancies," questions have occurred regarding these classifications since their inception in the early 1960s. FDA has, from time to time on request, issued interpretive opinion letters on such matters, as discussed below.

It is our understanding that the reference in FDA's regulations to "holding food during cooking" corresponds generally to conditions of use A and B in Table 2 of Section 176.170(c). In most cases, cooking applications involve conditions in which the food contacts the package or article at temperatures of 100°C or higher for an extended period of time. Since Condition of Use B permits the use of a substance in contact with food at temperatures of up to 100°C (i.e., the boiling point of water), we generally consider this clearance to include cooking. Thus, item 3.1a's clearance of specific olefin copolymers for use in articles that contact food "except for articles used for packing or holding food during cooking" covers all other conditions of use (C and below).

Our conclusion that conditions of use A and B cover "cooking?" in the container and, hence, that conditions of use C and below do not draws additional support from FDA's statements in a February 18, 1987 letter from Gerad L. McCowin, then Director of FDA's Division of Food and Color Additives. Specifically, Mr. McCowin states that "...we concur with you that microwave heating of food in the container (made from polymeric materials cleared for use in all food-contact applications other than holding food during cooking, i.e., conditions of use C-G listed in Table 2 of ? 175.300(d)), does not constitute holding food during cooking.'" (Emphasis added.) Although this letter was written in the context of microwave reheating, the clear implication from the cited language is that FDA considers conditions of use A and B to represent cooking.4 As discussed above, it is possible for some application involving maximum temperatures below 100°C to constitute "cooking." However, we would expect FDA to characterize conditions of use C-G generally as not involving "holding food during cooking," in accordance with Mr. McCowin's letter

Conditions of Use Identified in Testing "Recommendations"

FDA has issued a guidance document entitled "Guidance for Industry: Preparation of Food Contact Notifications and Food Additive Petitions for Food Contact Substances: Chemistry Recommendations," (April 2002), for use in collecting the necessary data for clearing the new use of a food-contact substance. One important data area is that of the possible migration of components of the food-contact article to food. The "Chemistry Recommendations" include a discussion of the factors that need to be considered in performing migration studies, including the recommended time and temperature conditions for a food-simulating migration test. To correlate actual use conditions with test conditions, FDA has defaulted primarily to reference to the Conditions of Use in Table 2 of Section 176.170(c) with corresponding time and temperature test conditions - much like the hierarchy of actual Conditions of Use A through H, the test conditions likewise follow a comparable progression. FDA has correlated the testing for Condition of Use A through H, as follows:

The test solutions should be analyzed at the end of an appropriate initial period (usually 2 hours or 30 minutes, as noted above), and again after 24, 96 and 240 hours.

FDA remarks that testing using Condition of Use C test conditions covers Conditions of Use C through G ("Frozen storage (no thermal treatment in the container)") and not C through H ("Frozen or refrigerated storage: Ready-prepared foods intended to be reheated in container at time of use"). This is not a change in interpretation, but a matter of clarification, as FDA has for some time been issuing clearances for Conditions of Use C through G when testing is performed using the recommended conditions for Condition of Use C.6

In recognition that the above "simple" view of Conditions of Use may not fit all intended use conditions, FDA also recommends other test conditions for use conditions that do not appear to fit the above paradigm; these are noted below, with some comments or observations.

FDA notes that articles intended for repeated use should be tested for 240 hours at the highest intended temperature of use. The test solutions should be analyzed for migration of the food-contact substance after 8, 72, and 240 hours.

For uncoated and pigment-coated paper and paperboard with latex binders, FDA indicates that these papers are intended for contact with food at temperatures less than 40°C for short periods of time. Consequently, the recommended migration test conditions are 24 hours at 40°C. It is important to recognize that this is an implied limitation - FDA's indication that "these papers are intended for contact with food at temperatures less than 40°C for short periods of time" has resulted in FDA imposing (on occasion) a limitation of room temperature use (i.e., Condition of Use E and below). This is, in effect, a recent imposition of restrictions where such limitations have not been placed in the past - the guidance document does not indicate that testing using the recommended test conditions will result in a Condition of Use limitation and it is our observation that testing has been performed using 40°C for 24 hours for uncoated and pigment-coated paper since 1988 (and possibly further back) without the imposition of Conditions of Use limitations. Nonetheless, FDA has, on occasions, concluded that the testing as set forth in the "Chemistry Recommendations" - 40°C for 24 hours - would be adequate to cover only Conditions of Use E (and below). This is an important factor, as there are some uses, albeit few in number, of uncoated and pigment-coated paper and paperboard that are used under conditions more severe than room temperature use.

With regard to adhesives, FDA notes that , in previous chemistry guidance documents for indirect additives, migration tests were not recommended for adhesives intended for use at room temperature or below and in accordance with 21 CFR 175.105 ("Adhesives"). This recommendation was based on consideration of Section 175.105 (a)(2) which specifies that the adhesive is either separated from food by a functional barrier, or the quantity of adhesive that contacts aqueous and fatty food is limited to the trace amount at seams and edges. For this reason, if a notifier/petitioner proposes to use an adhesive or adhesive component in accordance with the limitations of Section 175.105, migration levels for the substances generally will be assumed by FDA to be no greater than 50 ppb. FDA adds, that if the assumptions of Section 175.105 cannot be supported, data or calculations should be submitted to model the intended use of any adhesive component. If a notifier/petitioner wishes to perform migration testing, multilaminate samples should be fabricated with the maximum anticipated amount of the adhesive component and with the minimum thickness of the food-contact layer. The migration protocol corresponds to condition of use E.

With regard to contact limited to dry food with no free surface fat or oil, FDA indicates that migration testing is not recommended, although FDA notes that studies have shown migration of certain adjuvants into dry foods (e.g., low molecular weight adjuvants in contact with porous or powdered foods). FDA does not give details, but the presumption is that FDA does not recommend actual experimental studies because there is little expectation of migration of most food-contact substances to contacted dry food. At the recently held FDA Workshop on FCNs (October 15, 2002), Dr. Michael VanderVeer, a review Chemist at FDA, noted that migration levels for the substances generally will be assumed by FDA to be no greater than 50 ppb; this would be in accord with the FDA practice for adhesives (noted above). With regard to laminates and coextrusions, FDA observes that components of multilayer structures used above room temperature are the subject of two regulations - one that covers laminates used in the temperature range 120°F (49°C)-250°F (121°C) (21 CFR 177.1395) and the other that covers laminate structures used at temperatures of 250°F (121°C) and above (21 CFR 177.1390). Where non-food-contact layers are not separated from food by barriers preventing migration during expected use (or where the use of the non-food-contact layer material is not otherwise permitted), an appropriate FDA status must be established. FDA indicates that the test protocols noted above for Conditions of Use A through H may be appropriate for evaluating the level of migration from non-food-contact layers of some laminate structures. End uses that differ considerably from those considered in this guidance, however, should be the subject of special protocol development in consultation with FDA.

For boil-in-bag applications, FDA indicates that testing performed in accordance with the recommended Condition of Use C protocol would suffice.

With regard to testing for cooking or reheating food, FDA has struck off in a different direction by recommending testing conditions that are quite different that the Conditions of Use A through H conditions noted above - separate testing is recommended for dual-ovenable trays, microwave containers, and microwave heat-susceptor packaging.7

For dual ovenable trays use (conventional and microwave), FDA recommends that migration testing be performed at the maximum intended conventional oven cooking temperature for the longest intended cooking time, using a food oil, or a fatty-food simulant such as Miglyol 812. For microwave-only containers, FDA does not have a specific recommendation - instead, FDA's advice is to consult with FDA on any planned testing protocol prior to initiating migration testing. For microwave susceptor testing, FDA recommends that migration studies be conducted using a susceptor package in a microwave oven in a manner similar to that outlined in the article by Begley and Hollifield. 8

Comments

We find FDA's recommendations for migration testing to simulate cooking or reheating food, the last subject noted above, to be curious in light of the Agency's other recommended testing as well as the opinions that FDA has provided on related areas, especially considering literature data on the matter. Specifically, with regard to testing for microwave-only containers, we believe that it is sufficient to perform testing for 30 minutes at 100°C to adequately simulate the intended use. This belief is based on the known behavior of plastics in microwave ovens, namely, that plastics per se generally do not absorb significant amounts of microwave energy and, consequently, the plastics per se do not get heated in a microwave oven. Instead, it is the food that absorbs microwave energy and it is the temperature of the food that increases; in this way, the food heats the package. As most food has an appreciable water content, we would not expect the temperature of food to significantly exceed the boiling point of water when food is heated in a microwave oven. This is consistent with the February 18, 1987 McCowin letter noted above. Furthermore, it is consistent with FDA's recommendation, as noted above, that coverage for boil-in-bag applications may be achieved via testing using the recommended conditions for Condition of Use C; the high temperature phase of Condition of Use C is 30 minutes at 100°C.

One question that arises is - how hot does food get in a microwave oven? To answer this question we have turned to research performed by the United Kingdom's Ministry of Agriculture, Fisheries, and Food (MAFF)9. The research involved two types of microwave food-contact article - home-use ovenware and articles for pre-packaged foods. With regard to the first type of articles (housewares), measurements of the maximum temperature achieved at the food/container interface showed that most foods are predominantly aqueous and the final temperatures achieved did not significantly exceed 100°C. There were three notable exceptions - foods with high fat content (bacon) or high sugar content (meringue) ultimately reached temperatures on the order of 150°C. However, these seem to be the exception rather than the rule as the maximum temperature reached by other foods generally considered to be fatty foods, such as pate and chicken, did not appreciably exceed 100°C. For temperature testing of pre-packaged foods, these, too, generally did not significantly exceed 100°C, exceptions being pasta and sauce reaching 121°C and beef and rice reaching 114°C (other fatty foods did not significantly exceed 100°C).

Based on the foregoing, we believe it is reasonable to simulate microwave heating or cooking via testing for 30 minutes at 100°C, especially considering that this type of testing is properly conducted by pre-heating the solvent before decanting into the test cell (as recommended by FDA for Condition of Use C testing). In this way, the temperature of the test system will be close to or at 100°C for the entire duration of the test period and, consequently, will be an exaggeration of the actual temperature of the food in a microwave oven over the entire heating/cooking period as the temperatures achieved by food heated in a microwave experiences a gradient from room temperature even much lower temperature (such as frozen conditions).

The situation for food cooked in a conventional oven is not as clear. While the food also will achieve maximum temperatures based primarily on the nature of the food components (i.e., fatty vs aqueous) the difference between conventional cooking and microwave oven use is that the package is heated from the outside (the heated air in the oven) at temperatures higher than the food achieves - cooking in an oven set at 350°F (177°C) means that the package experiences a gradient of 177°C at the outside (air side) and the food temperature on inside (food side). For this reason, it is not as apparent what single temperature is most appropriate to use to simulate such conventional oven cooking. It would be useful to be able to turn to one or more migration studies designed to compare directly the results of migration to foods cooked in a conventional oven and migration to food simulants under conditions that correspond to "ordinary" test conditions, e.g., 2 hours at 121°C. In this way, if the results of such comparative testing are favorable, it would be possible to justify reliance on results from the recommended Condition of Use A migration testing as applicable for all foreseeable applications.

Prepared by Dr. Lester Borodinsky, Keller and Heckman LLP, for the December 5-6, 2002 meeting of The Society of the Plastics Industry, Inc.'s (SPI) Food, Drug, and Cosmetic Packaging Materials Committee, Scottsdale, Arizona, DoubleTree La Posada Resort.

1 Condition of use can be used to describe a wide variety of permitted uses that include not only those conditions relating to the time and temperature of contact, but also descriptions of types of food, upper (or even lower) quantitative limits on level of use off a substance, size or thickness of container/article restrictions, or points of use in the production of a food-contact material or article. The intention in this report is to focus solely on use conditions relating to time and temperature of use

2 21 C.F.R. § 175.300, which lists the components of coatings for metal substrates that FDA has cleared, is another regulation that contains a list of Conditions of Use. The Conditions of Use in Section 175.300 are essentially identical to those in Section 176.170. Since FDA invariably uses the Conditions of Use in Section 176.170 for general reference rather than the Conditions of Use listed in Section 175.300, we have, likewise, listed here the Conditions of Use in Section 176.170.

3 FDA maintains an inventory of threshold of regulation clearances on its website.

4 Although Mr. McCain's letter does not refer to Condition of Use H, "frozen or refrigerated storage; Ready-prepared foods intended to be reheated in container at time of use," we view the letter as supporting the conclusion that Condition of Use H does not represent cooking.

5 FDA notes that the 10 day period at 40°C should be extended to 30 days for testing involving polymers used at temperatures below their glass transition temperatures; polyethylene terephthalate (PET) and polystyrene are cited as examples.

6 While FDA has for some time been issuing clearances for Conditions of Use C through G when testing is performed using the recommended conditions for Condition of Use C, we note here that FDA has been quite inconsistent on this matter. For example while most groups of Conditions of Use have, in fact, been C-G or, where applicable, A-H or B-H (at least lately), there are many instances where FDA has grouped together C-H (likely the cause of FDA including the note regarding C-G), as well as B-G, D-H and even at least one instance of E-H. While there may be data-related reasons for such "excursions" from the intent of the note regarding Condition of Use C testing in the latest version of the Chemistry guidelines, we believe that FDA's interpretations have "wandered" from time to time.

7 FDA indicates that applications involving the heating and cooking of food at temperatures exceeding 121°C (250°F) are not included under Conditions of Use A-H.

8 Begley, T. H. and Hollifield, H. C., "Application of a polytetrafluoroethylene single-sided migration cell for measuring migration through microwave susceptor films," American Chemical Society Symposium Series 473: Food and Packaging Interactions II, Chapter 5, 53-66, 1991.

9 Castle, L., Jickells, S. M., Gilbert, J., and Harrison, N., "Migration testing of plastics and microwave-active materials for high temperature food-use applications," Food Additives and Contaminants, Vol. 7, 779-796, 1990.

More About SPI:   Vision and Mission . Membership . Business Units . Regional Offices . News and Publications . Calendar of Events . Terms and Conditions of Use