The term "active packaging" describes any packaging system that performs a function in addition to holding food. More specifically, active packaging interacts with the environment surrounding the food, thereby rendering the food inside fresher, safer, or more pleasing to the consumer. More than a passive barrier between food and the environment, active packaging systems employ materials that react with oxygen, prevent increased carbon dioxide concentrations in the package, or protect the food from degradation due to light exposure or water vapor. Another form of packaging currently being developed, known as "intelligent packaging," can indicate, by changing color, the temperature at which the food has been kept, the passage of time, or evidence of food spoilage.
Among the active packaging systems currently finding use with food products are so-called oxygen scavengers. Because oxygen accelerates the spoilage of many foods, and can effect flavor and color, oxygen scavengers are used to reduce oxygen levels in the headspace of food packages. The scavengers can either be incorporated into the packaging itself or added to the packaged food in small sachets. Similarly, ethylene scavengers are being utilized to trap the ethylene that is produced by ripening fruit or vegetables. By incorporating a chemical reagent into a packaging film to "gobble up" the ethylene, or by including ethylene-scavenging sachets, the shelf life of produce can be extended.
Current Regulations Are Up to the Task
The development of nascent active packaging technologies is giving rise to questions about how they should be regulated. Do additional regulatory requirements come into play when packages actually perform a function, beyond holding and storing food, that may affect the quality of food? How should testing be conducted on a food-contact substance that changes over time?
All food-contact substances must comply with the Federal Food, Drug, and Cosmetic Act (the Act). A substance that meets the Act's "food additive" definition will be considered "unsafe" unless it is used in accordance with an applicable food additive regulation or an effective food- contact notification (FCN). A "food additive" is defined in Section 201(s) of the Act as a substance that is reasonably expected to become a component of food under the intended conditions of use. Food additives that result from incidental exposure from a package may be referred to as indirect food additives (i.e., those not added directly to the food). Statutory exemptions from the "food additive" definition are provided for substances that are "generally recognized as safe" or are used in accordance with a sanction or approval issued prior to the enactment of the Food Additives Amendment of 1958. Some food-contact substances have received specific exemptions from FDA on a case-by-case basis under the "Threshold of Regulation" rule. Food that contains an "unsafe" food additive (i.e., one that is not being used in accordance with an applicable regulation, exemption, or notification) is deemed adulterated, per se, under Section 402(a)(2)(C) of the Act.
As discussed earlier, various chemicals or scavengers can be added to packaging with the aim of reducing the spoilage rate of food, or to maintain some characteristic of the food. The Code of Federal Regulations (C.F.R.) anticipates food additive substances that may be added to packaging with the intent that they have physical and technical effects on food-contact articles (21 C.F.R. § 174.5 ("General provisions applicable to indirect food additives")). The regulation specifies that these additives shall not exceed, where no limitations are specified, amounts required to accomplish the intended physical or technical effect in the food-contact article.
Further, under the Food, Drug, and Cosmetic Act, a company is entitled to determine independently whether the use of a substance for a particular food-contact application gives rise to a food additive situation. As the food additive definition implies, a suitable regulatory status for a substance may be established based upon a determination that the substance is not reasonably expected to become a component of food-the so-called "no migration" exemption.
FDA's guidelines for migration studies are available on the Agency's website. The guidelines note that, because a food-contact substance may be used in contact with many foods with different processing conditions and shelf lives, migration data should reflect the most severe time and temperature conditions to which the food-contact substance will be exposed. Exaggerated temperature conditions represent an acceleration of what may be expected to happen to a food-contact substance over time. Thus, FDA has anticipated that a food-contact substance may have a changing effect on a package over time. In fact, as an example, the guidance cites the effect of an antioxidant in preventing oxidation degradation of a particular polymer. The "technical effect" refers to the effect on the food-contact article, not on the food. Many oxygen scavengers and the like affect the headspace surrounding the food, but do not change or adulterate the food.
Therefore, determining migration of components from a package that is designed to change over time requires no different a theoretical approach than what currently exists. However, particular attention in designing migration testing protocols must be paid to detecting byproducts which may be formed. If a properly designed and conducted study shows that a food-contact substance is not reasonably expected to become a component of food under the intended conditions of use, it is not a food additive by definition, and may be used without any prior action by, or consultation with, FDA.
If Activity Is on Food as Well as the Package ...
On the other hand, certain packaging technologies involve additives that are intended to change the quality of the food itself. For example, enzymes can be added to the inside of citrus juice packaging in order to degrade the bitter compounds in the juice. Certainly, this type of packaging, designed to effect the food itself, must be evaluated as a direct food additive. Similar technologies, including edible films and packages intended to impart food ingredients, spices, additives, or supplements directly to food, all would be evaluated not as packaging but as direct food additives.
Thus, regulatory mechanisms exist that can adequately be used to evaluate active packaging. While there are some situations that seem to complicate the regulatory picture, standard FDA analysis brings it back into focus. For example, ethanol has been shown to increase the mold-free shelf life of bread and other baked products when sprayed onto product surfaces prior to packaging. As long as the packaging additive is protecting the packaging from growing mold, which in turn discourages the growth of mold in or on food, then the packaging is not a direct additive, but should be regulated as an indirect additive. This is because the mold inhibition is due to the conditions surrounding the food, and not because of a change in the food itself. If, however, an additive is actually bestowing a technical effect in the food itself, the additive has become a direct food additive.
Oxygen in a package can also lead to nutrient loss and microbial attack. Thus, the use of oxygen scavengers may actually have an effect in the food itself-not just the headspace in the package-and may have an antimicrobial effect as well. Such materials might be applied to inhibit mold growth on packaged baked goods and cheeses, given that most molds require oxygen to grow. Further, slowing the oxidation of vegetable oils can delay rancidity of the oil. Technology is also being developed to release high levels of carbon dioxide inside of food packages, which can inhibit surface growth of microorganisms.
Further regulatory considerations must be addressed when the packaging attempts to affect microbial activity. While stopping the formation of mold on a package may simply be considered "active packaging," adding a microbiological packaging material opens a completely new regulatory requirement. Any use of an antimicrobial in or on food packaging is regulated as a food additive by FDA, regardless of whether the antimicrobial is intended to have an ongoing effect on any portion of the packaging. Such uses include production aids, materials preservatives, or uses that have a sanitizing effect.
However, while jurisdiction over the safety of antimicrobial pesticide residues used in or on food packaging materials falls under the purview of FDA, these products also must be registered with the U.S. Environmental Protection Agency (EPA), as required by the Federal Insecticide, Fungicide, and Rodenticide Act. Further, when antimicrobial activity on packaging is intended to be ongoing, EPA exercises jurisdiction over food safety issues.
As new active packaging technologies find their way into global markets, the existing U.S. regulatory structures are sufficient to stand up to the task of assuring the safety of food contained inside. The more difficult challenge lies in characterizing the effects of the additives in packaging so as to determine if they should be considered food-contact substances, direct additives, or even antimicrobials. So before your firm goes to market with aqua-if-fresh, fuchsia-if-foul, mold-resistant active packaging, careful consideration is required to determine exactly what is being done to the package and to the food, how it is being done, and why.