Food Contact Compliance for Thermoformed Packaging: FDA and EU 10/2011

Two regulatory systems, and they do not recognise each other

Food contact compliance for thermoformed packaging is governed by two systems that approach the same question from opposite directions, and a pack that is compliant in one market is not automatically compliant in the other.

The United States regulates by substance. A polymer, an additive, a colourant or a processing aid is either cleared for food contact or it is not, and the clearance is specific to the substance and the conditions of use. If every substance in the pack is cleared, the pack is compliant.

The European Union regulates by material and migration. A positive list defines what may be used, and then the finished article has to demonstrate that it does not transfer more than a defined amount into food. A pack can be made entirely from listed substances and still fail, because it migrates too much.

Table 1 — The two systems. The EU places the final burden on whoever puts the article on the market, which is usually the converter or the brand owner.

The practical consequence is that a converter selling into both markets has to satisfy both, and the documentation for one does not substitute for the other. A resin with an FDA letter of no objection is not automatically on the EU positive list, and a resin on the EU list is not automatically cleared under 21 CFR.

The US route: substance by substance

In the US, the question is whether each substance in the pack is cleared for food contact under the intended conditions. For the common thermoforming polymers, that clearance usually exists as a citation in Title 21 of the Code of Federal Regulations.

Table 2 — The citations a converter is usually asked for. The additive and colourant rows are the ones that cause problems.

The polymer citation is rarely the problem. A PET or PP resin from a reputable supplier comes with the citation, and the extrusion of sheet from it does not change the substance. What does cause problems is everything else that ends up in the pack: the colourant masterbatch, the anti-block, the slip agent, the release agent, and the ink.

A masterbatch that is not cleared for food contact makes the whole pack non-compliant, even if it is 2% of the weight. This is the single most common compliance failure in thermoformed packaging, and it usually happens because a colour was matched quickly against a non-food grade.

The EU route: 10/2011, OML and SML

Regulation 10/2011 establishes a positive list of monomers, additives and polymer production aids, and sets two kinds of limit on what the finished article may transfer into food.

Bu overall migration limit (OML) caps the total mass of anything that migrates, regardless of what it is, at 10 mg per dm² of contact surface or 60 mg per kg of food, whichever is lower for the application. It is a blunt instrument and it catches formulations that are broadly too mobile.

Bu specific migration limit (SML) caps individual substances that are considered hazardous. These are listed per substance in Annex I, and they are the numbers that require testing.

Table 3 — Migration limits that matter for thermoformed packaging. Antimony is the one that catches PET converters.

Antimony is the number to watch on PET. It is used as a polymerisation catalyst, it remains in the resin at 200 to 300 ppm, and it migrates. The 0.04 mg/kg limit is achievable with a normal PET tray but it is not automatic, and it becomes harder with recycled content because rPET can carry a higher antimony level from feedstock that included bottle-grade resin with different catalyst levels.

Acetaldehyde is not an SML substance but it is a taste problem. PET degrades to acetaldehyde during extrusion and forming, and at concentrations in the tens of micrograms per kilogram it gives water a fruity off-taste. A water bottle specification typically limits acetaldehyde to 3 to 5 µg/L, and the same chemistry affects a thermoformed water cup.

Migration testing, in practice

Migration is measured by exposing the article to a food simulant under conditions that represent the intended use, then analysing the simulant. The simulant is chosen by food type and the conditions by temperature and time.

Table 4 — EU food simulants. Choosing the wrong one is the most common testing error, and it invalidates the result.

The test conditions are matched to the worst case the pack will see. A chilled ready-meal tray is tested at 10 days at 40 °C. A tray for hot filling is tested at 2 hours at 70 °C or higher. A tray that goes into an oven is tested at 2 hours at 100 °C or at 121 °C if it is retorted.

Two practical points matter more than the table. First, the test has to be run on the finished article, including the seal and any lid film, because the seal area is often the highest-migration part of the pack. Second, the contact area has to be the real one: a tray tested as a flat sheet will give a different result from the same tray tested as a formed cavity, because the forming stretched the material and thinned it.

Recycled content: the extra hurdle

Recycled plastic carries a risk that virgin plastic does not: it may have been in contact with something that was never intended for food. Both regulatory systems treat this as a separate question from the polymer itself.

In the US, the route is a food contact notification supported by a surrogate challenge test. The recycler deliberately contaminates feedstock with a set of surrogate compounds chosen to represent likely misuse — toluene, chlorobenzene, benzophenone, methyl salicylate and others — runs it through the full recycling process, and measures how much survives. The removal efficiency has to be high enough that the resulting resin is indistinguishable from virgin for food contact purposes.

In the EU, the route is approval of the recycling process under Regulation (EU) 2022/1616, which replaced the older 282/2008. The process is assessed by EFSA and registered, and the recycled material has to come from a registered process to be used in food contact.

Table 5 — Recycled content routes. The documentation is held by the recycler, not by the converter, and it has to be requested every time.

The failure mode here is commercial rather than technical. A converter buys rPET from a trader at a good price, forms a compliant tray, and discovers at the brand owner's audit that the recycler's process is not registered for the market in question. The material may be perfectly safe and completely undocumented, which in regulatory terms is the same as unsafe.

The Declaration of Compliance

The EU requires a written Declaration of Compliance (DoC) for every plastic article or material intended for food contact, and it is the document that gets asked for at an audit.

It has to state the identity of the article, the substances used that are subject to restriction, the migration test results or the basis for concluding compliance, the intended use conditions, and the date. It also has to state that the article complies with 1935/2004 and with 10/2011, and it has to be available in the language of the market.

A DoC that says "this product complies with EU food contact regulations" without listing substances, conditions and test results is not a DoC. It is a sentence. Auditors know the difference.

Where compliance actually breaks

In practice, most non-compliance in thermoformed packaging comes from four places, and none of them is the polymer.

Table 6 — Where compliance actually breaks. Only the last row is a polymer problem, and even then it is an additive rather than the resin.

The colourant. A masterbatch matched for appearance rather than for food contact. This is the most common single cause.

The release agent. A mould release spray applied to a food-contact surface is a food contact substance. An industrial silicone spray is not cleared, and it transfers.

The regrind. Trim scrap fed back into the extruder is generally acceptable if it is the same material from the same process, but it is not acceptable if the scrap includes printed material, material from a different product, or anything that was not food contact to begin with.

The recycled feedstock. Undocumented rPET, as described above.

There is also a process dimension that is easy to miss. Forming changes the material: it thins the wall, it orients the chains, and it can change crystallinity. A thinner wall migrates faster per unit area, and a more crystalline structure migrates more slowly. This is why a compliance dossier built on sheet data is not automatically valid for the formed part, and why migration testing on the finished tray is the only defensible evidence.