Note for Guidance for Food Contact Materials
Page 91 of 126
Therefore each analyst should select the appropriate alternative volatile medium taking
into account the general considerations mentioned in point 2.8.2. and construct for each
polymer the migration curves (migration against time for the different temperatures
prescribed by the Directive according to rules of Chapter 2). From these curves, the test
conditions to be used with the alternative test medium should be selected in order to
obtain the same results or better, migration values higher than those obtained by simulant
D. It is recommended that the choice of test conditions for the alternative volatile medium
is such that there is a sufficient margin of the security between the values obtained with
olive oil and those (higher) obtained with the volatile medium.
Directive 97/48/EC, Chapter 4, point 3.2, provides the following clause:
"Other tests, which use media having a very strong extraction power under very severe
test conditions, may be used if it is generally recognised, on the basis of scientific
evidence, that the results obtained using these tests ("extraction tests") are equal to or
higher than those obtained in the test with simulant D."
On this basis, rapid extraction tests using appropriate solvents such as diethylether, iso-
octane, ethanol 95% have been developed. A strong interaction with the polymer is
achieved and, as a consequence, a rapid extraction test is obtained. This allows the
amount of potential migrants to be determined which, in general, is higher than the
migration into food simulants. These extraction tests are most suitable for the overall
migration assessment of flexible packaging plastics with a thickness less than or equal to
300 µm. Appropriate test media were found it be iso-octane for non-polar plastics like
polyolefines and 95% ethanol for more polar plastics such as polyamide. In case of doubt,
both test media should be applied and the higher result used. Suitable test conditions were
found to be 24 hours at 40°C. The method can also be applied to thicker materials
provided the overall migration limit of 10 mg/dm² is not exceeded.
The method may also be suitable for specific migration assessment if it can be
demonstrated that it achieves almost complete extraction from a polymer to calculate then
the maximum possible migration under the assumption of total mass transfer.
Consult also the document "Methods of analysis".
Calculation of the maximum possible migration
Maximum possible migration can be calculated on the basis of residual or actual content
of the migrant in the polymer sample. For that purpose the content of migrant in the
polymer has to be determined by e.g. exhaustive extraction or dissolution of the polymer.
This procedure has the advantage that the results can be easily extrapolated to any other
food contact article made of the same polymer, with only one test having to be performed.
This calculation is made by applying the following formula:
Q x A x Lp x D
M = _______________