The U.S. Food and Drug Administration (FDA) has not issued any specific regulations on food packaging for microwave use. However, any package used in a food contact applications must be suitable for the intended use under FDA's good manufacturing practices (GMP) regulation found in Title 21 of the Code of Federal Regulations (CFR), Section 174.5 ("General provisions applicable to indirect food additives").

While FDA has not issued specific regulations concerning microwaveable food packaging, the intended use of a product is an important factor in establishing official FDA clearance of food contact substances under the Food Contact Notification (FCN) program. (To view a PackagingLaw.com article on the best approach to obtain FDA clearance for a food contact substance, click here.) Until April of 2006, FDA recognized the following temperature Conditions of Use: A ("High temperature heat-sterilized (e.g., over 212°F)"); B ("Boiling water sterilized"); C ("Hot filled or pasteurized above 150°F"); D ("Hot filled or pasteurized below 150°F"), E "(Room temperature filled and stored (no thermal treatment in the container)"); F ("Refrigerated storage (no thermal treatment in the container)"); G ("Frozen storage (no thermal treatment in the container)"); and H ("Frozen or refrigerated storage: Ready-prepared foods intended to be reheated in container at time of use").

In April of 2006, FDA modified its Conditions of Use to include Conditions of Use I ("Irradiation") and J ("Cooking at temperatures exceeding 250°F"), the latter of which is applicable to microwave heat susceptor materials. The following year, in December 2007, FDA updated its chemistry guidance for preparing FCN submissions. The new chemistry guidance includes specific protocols on testing for dual ovenable, microwaveable, and microwave heat susceptor materials.

Generally speaking, though, a clearance for Condition of Use A or B would permit use under standard microwave cooking temperatures (not susceptor); Conditions of Use C would permit use with microwave reheating applications (not susceptor). As for susceptor microwave applications, Condition of Use J would most likely be required.

The addition of the new Conditions of Use, especially J, could result in concerns about how they affect existing and future FDA clearances of food contact materials. For more information about this issue, you might wish to speak with an attorney at Keller and Heckman LLP.

In response to your question about customer requests for assurance that a packaging is safe for microwave use, it is not unusual for customers to ask for assurances of regulatory compliance for food-contact materials. In general, suppliers can provide assurance that a food package complies with applicable regulations and relevant quality specifications. For more information on different types of assurance that a food packaging manufacturer can provide to customers, please see a PackagingLaw.com article on this topic.