Non Food

MATERIALS IN CONTACT WITH FOODSTUFFS

Plastic raw materials: normative aspects

Plastic materials destined to food contact have to satisfy the general requirements established by the EC regulation 1935/2004 and by national normative D.P.R. 777 of 23.08.1982 and following modifications.

Fundamentally, they have to be produced in good manufacturing practice so that they do not transfer substances in such quantities to:

Make the food toxic
Imply a deterioration of their organoleptic characteristic

The evaluation of transfer of substances from plastic material to foodstuff is specifically regulated by DM 21/03/73 and following modifications (in Italy) and by Directive 2002/72/EC and following modifications in Europe. Both regulations establish:

A list of authorized substances for the manufacture of materials and objects. For this reason, Chelab laboratory offers a service to verify whether the substances used in the production of plastic materials are present in the positive lists
Possible restrictions of utilization of substances
Limits of overall and/or specific migrations

Overall migration means the quantity of substances that a material gives to a liquid that simulates the extractive capacity of the foodstuff: it cannot identify what is migrated, but it measures the total quantity of moved substances transferred from the material to the foodstuff in test conditions.

The test are performed using:

The simulants of foodstuffs, that are water, acetic acid 3%, ethanol 10% or other concentrations similar to the foodstuff; oil (see table 1 and Attachment II )
Times and temperatures correspond to worse condition of contact in the real life or to any information reported in the label of the product (see Table 2 and Attachment I)

The specific migration is instead the quantificatin, in the simulant liquid, of the substance/s used in the production of the material. It is clear that to execute these tests it is necessary to know what substances were used in the production of the finished product.

Table 1 Type of foodstuffs and simulants of foodstuffs - from Directive 82/711/EEC
Abbrevation	simulant	Type of product
simulant A	Distilled water or water with similar quality	Aqueus foodstuffs pH > 4,5
simulant B	Acetic acid 3% (w/v) in aqueus solution	Acid foodstuffs pH < 4,5
simulant C	Ethanol 10% (v/v) in aqueous solution	foodstuffs with alcohol
simulant D	Rectified olive oil, if for technical reasons connected with the method of analysis is necessary to use other simulants, the olive oil has to be replaced with other mixture of synthetic triglycerides or with sunflower oil	Alimentary products based of fatty substances
nothing	Nothing	Dried foodstuffs

Table 2 Agreed conditions for migration test with simulants of foodstuffs - from Directive 82/711/EEC

Contact conditions in the expected worse utilization	Conditions of test

Period of contact	Time of test
t < o = 5 min	See attach II
5 min < t < 0,5 hours	0,5 hours
0,5 ore < t < 1 hours	1 hours
1 ora < t < 2 hours	2 hours
2 ore < t < 4 hours	4 hours
4 ore < t < 24 hours	24 hours
t > 24 hours	10 days

Temperature of contact	Test temperature
T < o = 5°C	5°C
5°C < T < 20°C	20°C
20°C < T < 40°C	40°C
40°C < T < 70°C	70°C
70°C < T < 100°C o t of reflux	100°C
100°C < T < 121°C	121°C *
121°C < T < 130°C	130°C *
130°C < T < 150°C	150°C *
T > 150°C	175°C *

(*) This temperature is used only with the simulant D. For the simulant A, B or C the test can be substituted with a test at 100°C or to reflux temperature for a period corresponding to four times superior to the chosen period based to general rules indicated on paragraph 1.

As follows we report the main methods uesed for the determination of overall migration in simulant aqueos liquid (water, acetic acid, and ethanol) and in the simulant liquid oil. All test of global migration are SINAL accredited.

TEST OF OVERALL MIGRATION IN SIMULANT AQUEOUS LIQUID (water, acetic acid 3%, ethanol 10%)

put the material to analyze into contact with simulant liquid (if it is a container it has to be full and if it is a film it has to put in a special cell that allow to put into contact only the face destined to food contact),
once the contact time is passed, the simulant liquid coming from the test is dried
the weighed residue constitutes the data of overall migration

TEST OF OVERALL MIGRATION IN LIQUID OIL SIMULANT (OLIVE (olive oil or sunflower oil )

the sample is conditioned to temperature and humidity controlled (so its weight does not depend on atmospheric factors)
the sample is weighed (P1)
the sample is put into contact with oil (if it is a container it has to be filled, if it is a film it has to be put in a special cell, and so on)
once the contact time is passed, the oil must be removed from the material that can remain “greasy” of oil
the sample is conditioned to initial temperature and humidity and is weighed (P2)
the residue of oil present in the surface is extracted by an organic solvent, it is evaporated and weighed (Pext)
the MAXIMUM PONDERAL MIGRATION is calculated considering the initial weight, final weight and weight of organic extract; (this value is overestimated because further to the oil, the solvent can extract little quantities of material that compose the object)

Maximum ponderal migration (mg/dm²) = [P1 – (P2 – Pext)] / surface
When the value of MAXIMUM PONDERAL MIGRATION exceeds the LEGAL LIMIT, it is necessary to exactly quantify the oil absorbed by the sample during the contact. The DETERMINATION OF METHYL ESTERS OF FATTY ACID is performed by gas chromatographic analysis with FID regulator. The quantity of obtained oil is subtracted from the weight of the examined sample already put into contact with simulant solvent and we obtain the value of the overall migration (mg/dm²) = [P1 – (P2 – Polio)] / surface

Since Pext ³ Polio will always Mmax ³ Mglob

MIGRATION TESTS IN SIMULANT LIQUIDS SUBSTITUTIVE OF FATTY SUBSTANCES

It might happen – for legal reasons connected to the nature of the material – that the migration test in oil cannot be concluded obtaining an analytical satisfactory result (for example: plastic porous material that absorbs the oil and it doesn’t allow the complete extraction with the solvent). In these cases, the regulation provides to perform SUBSTITUTIVE tests using isooctane, ethanol 95% and MPPO instead of oil, in conditions of test corresponding to those used in the test in oil (simulant D).
In this case, our laboratory will take care to inform the costumer about of the contact conditions to be taken in the substitute tests.
Contemporarily to the overall migration, if during the production phase are used restrictive substances (known as LMS, limits of SPECIFIC MIGRATION) it is necessary to evaluate if the finished products meet the limits. For this reason, together with the overall migration are performed specific migrations. They consist in the determinatin of single monomers and additives (for example: monomer caprolactam used in the production of nylon 6, or N, N-bis (2- hydroxyethil) alkyl (C8-C18) amines used as antistatic agents in many polymers) in the simulant liquid put into contact with the object in the same test conditions used in the overall migration tests.
For some substances the law - rather than be expressed in terms of LMS - establishes the maximum residue on the material as received. Therefore the analysis, instead of being researched substance in the simulant liquid of cession , has to be effected on plastic material. For example CVM o 1,33 butadiene.
The regulation EC 1935/2004 also establishes that the materials in contact with foodstuffs do not even have to cause a DETERIORATION OF ORGANOLEPTIC CHARACTERISTICS.
It is not uncommon, however, that the phenomenon of sensory contamination of the foodstuff are contested as to the suitability of the packaging.

In order to evaluate in advance the possibility that a contact with packaging material bring to an olfactory and/or taste defect of the foodstuff it is possible to perform tests to verify the organoleptic qualification of the packaging material. Therefore, olfactory and taste tests are made on foodstuff or on their simulants put into contact with the packagings investigated. Sensory tests performed at Chelab laboratory refer to internationally recognized standards (for example UNI 10192); yet, on the basis of specific needs of the Costumer we are able to suggest the suitable analysis still respecting the basic requirements of rules of sensory analysis. Since the origin of an organoleptic defect can derive from different causes (for example: migration of odorigenous substances from the packaging to the foodstuff and/or to the head space inside the packaging; inadequate protection of the foodstuff from external environment; reaction of substances present in the packaging with substances contained in the foodstuff) it is possible to conduct activity of research, thanks to the most advanced instrumentation and to identify and quantify volatile substances that might migrate from the packaging to the foodstuff and to the headspace inside the packaging.

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