| Migration | Transfer of chemicals from packaging and other food contact materials to food. Both intentionally added substances (IAS) and nonintentionally added substances (NIAS) can migrate. |
| NIAS |
(Non-intentionally added substances) Any impurities and unwanted substances which have not been added into the production processes for a technological reason. They are present in chemical product or in food contact articles due to side reactions, decomposition, or non-complete reaction. NIAS can be formed during the manufacture of a chemical, but also during papermaking process. |
Migration, the process in which substances move from one material to another, is an unavoidable natural phenomenon that occurs when any two materials come into contact. When it comes to food packaging we’re talking about chemicals migrating from the board to the food itself. The extent to which this happens is affected by things like the type of packaging material and the food, as well as storage time and temperature.
Communication and transparency
Food board manufacturers need to be 100% sure that their product is safe to use and that the whole supply chain is transparent and traceable. “Part of that involves the chemicals Kemira provides to give the board the qualities it needs, so it’s our responsibility to analyze the safety of the substances in our products to ensure they meet the regulatory requirements,” explains Tiina Hyytinen, Manager, Product Stewardship and Regulatory Affairs at Kemira.
“We also carry out risk assessments for chemical substances to ensure they are safe for use in food contact applications and communicate to our customers about substances that have a specific migration limit – the maximum amount of that substance permitted to transfer from the packaging into the food,” Tiina explains. “Essentially we want to make their lives as easy as possible by giving them all the information they need up front, so there are no lingering question marks.”
Limited limits
Only a handful of substances have specific migration limits set by the authorities. For example, all identified NIAS do not have a regulated migration limit available, so they are not specifically covered by end tests. If there is no set limit it is derived based on toxicologists’ assessment of the “no-adverse-effect” level of each substance according to standard guidelines. “For these substances we use the tolerable daily intake value that describes the daily amount of a chemical that has been assessed safe for a human being to be exposed to over their lifetime,” explains Anita Laakkonen, Senior Specialist, Product Safety and Regulatory Affairs at Kemira.
One example of substances that do have limits is monomers, which are used in the production of polymeric materials like barrier materials that stop packaging from leaking. In Europe the EU has defined clear, harmonized regulations for plastic food contact materials and the specific limits for monomers are part of this.
Testing, testing
The evaluation that ensure our substances comply with all the relevant regulations and standards can either be theoretical – calculations of how much of a certain dose of a chemical will migrate into 1 kilo of food – or, more commonly, based on lab tests of packaging material samples. This is done by comparing a representative sample of packaging material and a reference sample that have been dipped in a food-simulant for a set period of time. These simulants can mimic different types of food – dry, greasy, or acidic for example. The content of substance in the simulants are then compared to see how much of the chemical is migrated. The level of migration mostly depends on the packaging material contents rather than the food type, but it’s always about the specific interaction of the two.
Food packaging manufacturers assume the final responsibility for ensuring that the product has been properly tested because the whole production process impacts what kind of chemical substances the packaging could end up containing. Also NIAS formation is production process specific and their general risk assessment covering all use scenarios is not possible. It’s therefore better to have a representative sample from the actual production process. Manufacturers also have the knowledge about the type of food the packaging material will be used with, which is also critical when conducting the tests.
Kemira takes its role in the food packaging supply chain very seriously. “By testing and evaluating our chemicals we are not only ensuring the safety and quality of our products, we’re providing a sort of pre-screening service and can make manufacturers aware of any potential issues to be considered further along in the production process,” concludes Tiina.
