Compliance testing of food contact materials     EU    FDA   

EU testing         Introduction    simulants&conditions    overall migration    specific migration    residual content    other testing  

Specific migration testing

Specific migration is the amount of a specific component that migrates from the food contact material to the food during contact. There are several ways to demonstrate compliance of the Specific Migration Limits (SMLs) set in EU food contact legislation. The generic approach is shown in Figure below. For every component with a specific migration limit, which is present in a material the procedure must be completed

 Worst-case calculation

If the amount of a component that is available to migrate is so small that even if everything were to migrate to the food the migration limit cannot be exceeded, it is clear that the SML cannot be exceeded. This calculation can be made using data that are already available like chemical’s ingredient specification or the amount of chemical added. As an alternative the residual amount present expressed per unit of area (QMA) can be determined. If the value obtained is above the specific migration limit mathematical modeling can be used to calculate how much can potentially migrate to the food.

Mathematical modeling

Mathematical modeling of specific migration is described in more detail in chapter  -- of this book. Mathematical modeling can be a relatively cheap and fast way to determine maximum specific migration. Mathematical modeling can be done using several programs available on the Internet or others that are commercially available. The following considerations must be taken into account when using mathematical modeling:

• The concentration of the component in the food contact material must be known.

•  The component may not be charged.

•  The concentration of the component should be homogeneous in the food contact material (an antistatic additive is therefore excluded).

• Sufficient information about the migration behavior of components in the polymer must be known (so far, modeling can only be performed in some polymers). Research continues to expand the application range.

• The temperatures to which the polymers are exposed must be below certain limits because above these (which are unique for each type of polymer) the diffusion behavior of the migrant is changing and cannot be calculated using the migration models.

•  It is possible to demonstrate that specific migration is smaller than the SML, but because mathematical modeling provides an overestimation of migration it is not possible to state that an SML is exceeded.

• Analytical error of overall migration is quite large, as is shown in overall migration section. Therefore, analytical error must be added to the overall migration value found before it is compared with the SML.

• When overall migration into aqueous simulants is determined, the simulant is evaporated. Therefore, this approach of checking an SML via  overall migration cannot be used for volatile components with values of  overall migration into aqueous simulants, because they will not be included in  overall migration.

• A small area of packaging is in contact with large amounts of food (for example a cap on a bottle), or
• When a large value for the SML applies, or
• When the food contact material is in contact with an object with a large reduction factor. 

If the steps described above could not demonstrate compliance with an SML, then specific migration must be determined analytically. After the simulant is separated from the sample, the specific migration can be determined using a wide variety of analytical techniques, such as high performance liquid chromatography (HPLC) and gas chromatography (GC) with a wide range of detection methods.

General information about how to determine specific migration is available in CEN document “EN 13130-1:2004 Materials and articles in contact with foodstuffs - Plastics substances subject to limitation - Part 1: Guide to test methods for the specific migration of substances from plastics to foods and food simulants and the determination of substances in plastics and the selection of conditions of exposure to food simulants”.  CEN has also established methods for the determination of some specific migration. The table show a list of components for which CEN methods are established.

Another source of analytical methods is on the website of JRC.

Back to Top