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Frequently Asked Questions on Food Contact Notifications: Chemical Requirements

March 1, 2001

How should migration test results be validated?

To properly validate migration study results, the notifier should use an extract from the control sample (sample made without the test substance) or use the extract from a replicate test sample. The extracts should then be spiked, prior to work up. For non-detected analyses, the extract should be spiked at the level of detection. For detected analyses, the extract should be spiked with 1/2 times, 1 times, and 2 times the level of detection. Finally, validation analyses should be conducted in triplicate.

Should time and temperature conditions be considered?

It is well known that both time and temperature affect migration. For food packaging generally, migration studies usually involve two phases: a simulation of initial thermal processing of the packaged food (e.g., hot-filling), and a simulation of shelf storage that is accomplished by accelerated short-term testing. FDA's recommendations for migration testing include default times and temperatures that correspond to the most common actual use conditions.

What chemistry information is required in a Food-Contact Notification?

Generally speaking, a Food Contact Notification should include:

  • The chemical identity of the food-contact substance;
  • Manufacturing information (raw materials used, time and temperatures, purification processes, and impurity levels);
  • Information on the properties of the food-contact substance and specifications (e.g., molecular weight, viscosity);
  • Use level and conditions of use;
  • The intended technical effect of the food-contact substance (e.g., enhances the oxygen barrier properties of a material);
  • A determination of how much of the food-contact substance is expected to be present in the contacted food (e.g., analysis of food, migration studies, or modeling); and
  • An exposure estimate.

What food-simulating solvents should be used in a migration study?

Although analyses of actual foods is permissible under FDA's Guidance for Industry ? Preparation of Premarket Notifications for Food-Contact Substances: Chemistry Recommendations, such media often pose practical problems with the testing. For aqueous acidic, and low alcohol (less than 15%) foods, 10% ethanol is the appropriate solvent to use. For high alcohol foods, 50% ethanol. And, to simulate fatty foods, FDA suggests using food oil or synthetic fat (Miglyol 812 or HB307), or, alternatively, 95% ethanol for polyolefins, and 50% ethanol for rigid polyvinyl chloride, polystyrene, polyesters, and polycarbonate.

What should be considered in preparing test samples for migration studies?

The form of the test samples plays an important role in the interpretation of migration results. If using a polymer, the properties of the polymer should be considered. The notifier should choose representative or worst-case properties for testing. If possible, actual food-contact articles or portions thereof (e.g., container walls), or test plaques should be used. In addition, the food-contact substance should be present in the samples at the maximum use level. Depending on the intended use, the notifier may want to use a single or double-sided migration cell. The single-side migration cell (where only one side of the sample is exposed to solvent) is appropriate if the food-contact substance will be applied to a substrate and the notifier is interested in establishing whether the substrate provides a functional barrier to migration of the food-contact substance.

What should be included in a migration study report submitted with an FCN?

The testing should be described in detail, including sample preparation, experimental design, analytical or test methods, and validation procedures. The report should show representative calculations and include calibration curves. Representative chromatograms should also be included in the report. Generally, the results should be reported in units of amount per surface area, e.g., mg/in².

Why does the FDA require specifications and supporting analytical data?

Specifications are critical in identifying and demonstrating control of impurity levels (e.g., carcinogenic contaminants), and physical properties of the food-contact substance. Specifications ensure that the food-contact substance, when tested, will be equivalent to that which is sold.