Polymer Packaging And Food Pp

Institute of Polymers - BAS Laboratory of Bioactive Polymers `

Polymer Packaging and Food: Migration of Substances D. Paneva, N. Manolova, I. Rashkov

BG/05/B/F/PP-166054

www.e-fost.org

Contents: Migration of substances from the packaging to food – generalities Legislation related to the migration of harmful substances to food Analytical methods and mathematical models used to study the migration to food Particular examples for food contamination with substances from the polymer packaging Polymer additives Residual monomers and oligomers Other contaminants migrating from the polymer packaging

The term “migration” of undesirable substances in respect to polymer food packaging is used to describe the two-way transfer of substances in the system package-food-environment.

Schematic representation of diffusion processes occurring at the polymer-food (solution) interface

TWO TYPES OF MIGRATION ARE DISTINGUISHED:

overall migration (often referred to as global migration) the transfer of all components that are able to migrate per unit area of packaging material regardless of their toxicity or non-toxicity

!

specific migration

the migration of only one component

One of the main criteria when choosing the packaging material is that the levels and the toxicity of all its ingredients (stabilizers, plasticizers, antioxidants, colouring agent, etc.) will not result in deterioration of the food flavour and to chronic damages to the consumers’ health even if some migration takes place.

Legislation related to the migration of harmful substances to food The requirements in terms of food safety and consumers’ health care are one of the major priorities in the EU countries.

The decision for usage of particular polymer material for production of food packages is based on compromises – it is estimated if the benefits of its application are more than the risks for the human health.

The risks in the usage of a polymer material consist in the possibility of migration of a part of the substances leading to deterioration of the quality of the food product or increasing its toxicity at prolonged use.

There are legislative regulations in EU (called Directives) on materials and articles intended to come into contact with food that establish the maximum permitted concentrations of these substances, methods for their analysis, as well as mathematical models for predicting their migration.

Legislation related to the migration of harmful substances to food The EU Directives concerning migration of substances from the packaging material into food could be divided into three categories: (1) Directives applicable to all materials and articles; (2) Directives applicable to one category of materials and articles; (3) Directives related to individual substances.

The Framework Directive 76/893/EEC of November 26, 1976 replaced by 89/109/EEC of December 21, 1988 establishes two general principles: (1) The principle of the “inertness” of the packaging material and the “purity” of the food; (2) The principle of “positive labelling”

Analytical methods and mathematical models used to study the migration to food

Does the material meet the requirements? Polymer identification Spectral methods (IR and NMR analyses) Analysis of volatile ingredients (gas chromatography) Analysis of non-volatile ingredients (NMR, gas chromatography, mass spectrometry, liquid chromatography, UV spectroscopy) Reaction products as migrating components, impurities Mutagenicity of the extracts

Extraction

Alternative test Prediction, modeling

Transfer into volatile solvents: overall migration specific migration Migration

Migration into fatty food simulant: overall migration specific migration

IR, UV and NMR – infrared, ultraviolet and nuclear magnetic resonance spectroscopy General strategy for studying the migration of substances from the polymer packaging into food. The alternative methods for studying are shown as well.

Particular examples for food contamination with substances from the polymer packaging Main contaminants that can migrate from a polymer packaging into food

additives included in the packaging

residual monomers and oligomers

other contaminants (e.g., residual solvents, pigments, other organic compounds)

For foreseeing the possibilities these contaminants to be transported into food it is necessary to precisely know the chemical structure and the physico-chemical behaviour of all ingredients of the packaging in different media.

Particular examples for food contamination with substances from the polymer packaging additives included in the packaging

an additive is a substance that is an auxiliary ingredient for improvement of the physico-mechanical properties of the polymers during their processing and use

Depending on their application, the additives can be divided into the following groups: plasticizers, antioxidants, UV-stabilizers, lubricants.

The major requirement in the case of food packaging is the additive in the plastic from which they are fabricated to meet the requirements for “food purposes”.

Particular examples for food contamination with substances from the polymer packaging additives included in the packaging

Antioxidants (stabilizers, anti-aging additives)

for prevention the degradation of the polymers during their processing, storage and use

OH (H3C)3C

Most of the antioxidants are non-toxic and have a satisfactory stabilizing effect. C(CH3)3

CH3 2,6-di-tert-butyl-p-cresol (DBC)

DBC is a substance, which is soluble in fats-containing medium. It has been first used as an antioxidative additive in food products (E321) DBC is used as antioxidant in polymer packaging from high-density polyethylene

Particular examples for food contamination with substances from the polymer packaging additives included in the packaging

R R C R, R

Antioxidants (stabilizers, anti-aging additives)

Irganox 1010

OH

CH2 CH2 C

O

O

OH (H3C)3C

tetrakis[methylene(3,5-di-tertbutylhydroxy hydrocinnamate)] methane

C(CH3)3

R = (H3C)3C

C(CH3)3

Irganox 1076 octadecyl 3,5-di-tert-butyl4-hydroxyhydrocinnamate

CH2 CH2 C

O

C18H37

O They are used as antioxidants in plastics from low-density polyethylene and polypropylene.

Particular examples for food contamination with substances from the polymer packaging additives included in the packaging

Antioxidants (stabilizers, anti-aging additives)

Irganox 1076 (polypropylene, 1.5 h, 135 0С) Irganox 1010 (low-density polyethylene, 1.5 h, 95 0С)

Migrated amount (µ g/dm2)

5000

Irganox 1010 (polypropylene, 1.5 h, 100

0С)

4500 4000

R R C R, R

OH C(CH3)3

R = (H3C)3C

Irganox 1010

3500

CH2 CH2 C

O

O

3000 2500 2000

OH (H3C)3C

1500

C(CH3)3

Irganox 1076

1000 500 0

CH2 CH2 C A

water

B skim milk

C chicken broth

D vegetable oil

O

C 18H37

O

The rate of their migration into food depends on the polymer nature, antioxidant type and the composition of the food product.

Particular examples for food contamination with substances from the polymer packaging additives included in the packaging

Plasticizers Compound that is added to the polymer for facilitating its processing

The phthalic acid esters have been the most widely used plasticizers.

O C 2H5 COCH2CH(CH2)3CH3 COCH2CH(CH2)3CH3 O C 2H5 di-2-ethyl hexyl phthalate or dioctyl phthalate

approved for use as plasticizer in the manufacture of food packaging materials for food with high water content the migration of phthalates depends on pH of the soft drinks as well as on the nature of the used preservative

!

phthalates harm the liver; they can cause weight loss, abortion, and birth of dead or prematurely born children; they have toxic, carcinogenic, mutagenic and teratogenic effect; phthalates imitate the estrogens, thus rendering harmful effect on the male sex glands.

Particular examples for food contamination with substances from the polymer packaging additives included in the packaging

ca. 90% of all plasticizers are used with PVC The copolymers of poly(vinyl chloride) and poly(vinylidene chloride) are plasticized with up to 5% of acetyltributyl citrate. CO O (CH2)3 CH3

CH3 (CH2)3 O CO CH2 C CH2 CO O (CH2)3 CH3 O CO CH3 Migration of acetyltributyl citrate into microwave-cooked foods

Particular examples for food contamination with substances from the polymer packaging additives included in the packaging

antistatic agents

Other types of additives ethoxylated fatty acid, polyhydrated alcohols, non-ionogenic substances that contain quaternized ammonium groups

“antifog” agents

antiblocking agents

dyes and pigments

foaming or blowing agents

fatty acid esters (glycerol stearate and sorbitol stearate); content: 0.5 – 4 % stearamide, calcium stearate, alkylamines or quaternized alkylamine compounds; quartz, clays, starch and silicones; content: 0.1 – 0.5 % activated carbon, titanium dioxide (imparts white colour), iron oxide (red colour), cadmium sulphide (yellow colour), molibdates (orange colour), ultramarine blue, ferric ammonium ferrocyanide (blue colour), chrome green, and blue and green copper phthalocyanine. СО2 or aliphatic hydrocarbons (for example, pentane)

Particular examples for food contamination with substances from the polymer packaging The monomers are much more toxic than the residual monomers and corresponding polymers oligomers

Polystyrene is widely applied in the fabrication of packaging for yoghurt, water, hot and cold drinks, oil.

CH CH2

It has been found that the migration of styrene from polystyrene cups containing hot or cold drink is about 0.025% per cup. the product of styrene metabolism – styrene oxide, is a mutagen. styrene acts as a depressant (it causes neurological diseases) and is harmful for the liver.

styrene

!!

styrene vapours cause irritation of eyes, nose, throat, and skin. in the human body styrene simulates the estrogens, and therefore could harm the normal functions of the hormones (problems with the thyroid gland, unregulated menstrual cycle and other hormones-related problems, including breast and prostate cancer)

The higher the fat contents, the higher the migration of styrene into food.

Particular examples for food contamination with substances from the polymer packaging residual monomers and oligomers

CH2 CH Cl vinyl chloride

CH2 CH CN acrylonitrile

! highly toxic substance - its levels in poly(vinyl chloride) food packaging materials are controlled extremely strictly Any package that contains 275 ppb residual vinyl chloride cannot be used for food applications!!!

comonomer which presents in several copolymers used as food packaging materials; in terpolymers containing styrene or butadiene its content may reach up to 70% In 1975, a regulation that limited residual monomer levels to 80 ppm in the wall of the bottle has been published and enacted that monomer migration into the food product could not be greater than 0.3 ppm.

Particular examples for food contamination with substances from the polymer packaging other contaminants (e,g, residual solvents, pigments, other organic compounds)

Due to the complex structure and chemical composition of the packaging materials, it is possible during their processing and use different reactions to occur that could result in obtaining of harmful substances, which at a next stage could migrate into the food product. The identification and analysis of the obtained substances migrated into the food product is a very difficult task.

Systematic studies on each system polymer packaging material – food product is necessary to be conducted. The most modern trend - replacement of the most of the components (main polymer, plasticizers, stabilizers, colouring agents) in the packaging ! material with natural and non-toxic for the human health substances. Such type of replacement will lead to obtaining of polymer material that will not release toxic substances into the food product, and subsequently the risk for the human health will be drastically reduced.

Acknowledgments: BG/05/B/F/PP-166054

www.e-fost.org

Bulgarian Academy of Sciences Institute of Polymers N. Manolova, O. Stoilova, D. Paneva, I. Rashkov

Polymeric materials from synthetic and natural polymers for food packaging and food preservation Leonardo da Vinci II

Specific content issues in: e-Reference Tools for VET Trainers in Food Industry Pilot project

Grant ТК CH 1605 Novel functional nanostructured materials for electrochemical detection of pesticides in foods

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