Note for Guidance for Food Contact Materials
Page 88 of 126
Assuming a reasonable effort has been made to develop a sensitive method, the use
of a substitute test can be accepted. A typical example is an antioxidant, with a low
SML, which cannot be isolated from the fat simulant to an acceptable level.
2.8.2 Directive 97/48/EC, Chapter 3, point 2, provides the following clause, which applies
to overall and specific migration:
"By derogation..., it may be possible to omit one or two of the substitute tests ... if these
tests are generally recognised not appropriate for the sample under consideration on the
basis of scientific evidence".
Both overall migration and specific migration are influenced by the physical properties of
the polymer, the migrant and the simulant. Without being exhaustive, the following
parameters will influence migration into simulants and also mass transfer into test media:
physical properties and polarity of the polymer;
diffusivity of the migrant in the polymer;
Interaction of the simulant or the test medium with the polymer or with the migrants;
time and temperature conditions of the test.
Penetration of the polymer by olive oil (or other non-volatile fatty simulants) can greatly
accelerate the migration process. Therefore the interaction of substitute media with the
material should be close or slightly greater than that of simulant D in the corresponding
time and temperature conditions (Directive 97/48/EC, Table 4). However the
determination of the interaction of the simulant or the test medium with the polymer may
be complex. The affinity of a migrant with a food simulant can be reflected in some cases
by its solubility in the simulant. In these cases mass transfer is expected to be low when
the migrant is poorly soluble in the simulant or in the test medium. Therefore, comparison
of the solubility (or solubility range) in simulant D and in test media in the corresponding
time and temperature conditions (see Directive 97/48/EC, table 4) may be used as a first
indication to help select the most suitable test medium.
For example: Ethanol 95% is a suitable test medium for non-polar polymers such as
polyolefines and also for plastics of medium polarity like PVC and PET. However it is
inappropriate for strong polar polymers (e.g. PA), for which iso-octane can be used if the
limits are exceeded.
It is recommended that analysts maintain the comparison curves of simulant D and the
test medium used in the alternative test. These curves should be requested by the national
enforcement authorities as well as the Commission Services to verify the validity of the
omission of a test medium. These comparison curves shall be always added in the
petitions in order to have an EU agreement.
The majority of published data demonstrate the suitability of iso-octane as a volatile test
medium in the substitute fat test for the determination of overall migration. In EC