Polymer Packaging and Food PP

PolymerPolymer Packaging and Food:Packaging and Food: Migration of SubstancesMigration of Substances

InstituteInstitute of Polymersof Polymers - - BASBASLaboratoryLaboratory of Bioactive Polymersof Bioactive Polymers

`

BG/05/B/F/PP-166054BG/05/B/F/PP-166054 www.e-fost.org

D. Paneva, N. Manolova, I. Rashkov

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 tostudy the migration to food

Particular examples for food contamination with substancesfrom the polymer packaging

Polymer additivesResidual monomers and oligomersOther contaminants migrating from the polymer packaging

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

The term “migration” of undesirable substances in respect topolymer food packaging is used to describe the two-way transfer of

substances in the system package-food-environment.

TWO TYPES OF MIGRATION ARE DISTINGUISHED:

overall migration (often referred to as

global migration)specific migration

the transfer of all components that are able to migrate per unit area of

packaging material regardless of their toxicity or non-toxicity

the migration of only onecomponent

One of the main criteria when choosing the packaging material isthat 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.

!


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 packagesis 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.


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”

Does the material meet the requirements?

Mutagenicity of the extracts

Analysis of non-volatileingredients

(NMR, gas chromatography,mass spectrometry,

liquid chromatography, UV spectroscopy)

Reaction products asmigrating components,

impurities

Alternativetest

Prediction,modeling

Transfer into volatilesolvents:

overall migrationspecific migration

Migration into fatty food simulant:

overall migrationspecific migration

Migration

Analysis of volatile ingredients

(gas chromatography)

IR, UV and NMR – infrared, ultraviolet and nuclear magnetic resonance spectroscopy

Polymer identificationSpectral methods (IR and NMR analyses)

Extraction

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

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

residual monomers and oligomers

additives included in the packaging

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.



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”.



Antioxidants (stabilizers, anti-aging additives) for prevention the

degradation of the polymers during their processing, storage and use

OHC(CH3)3(H3C)3C

CH3

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

Most of the antioxidants are non-toxic and have a satisfactory stabilizing effect.

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 packagingfrom high-density polyethylene


additives included in the packaging Antioxidants (stabilizers, anti-aging additives)

OHC(CH3)3(H3C)3C

CH2 CH2 C

O

O

CR

R,RR

R =Irganox 1010

tetrakis[methylene(3,5-di-tert-butylhydroxy hydrocinnamate)]

methane

OHC(CH3)3(H3C)3C

CH2 CH2 C

O

O C18H37

Irganox 1076octadecyl 3,5-di-tert-butyl-4-hydroxyhydrocinnamate

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


additives included in the packaging Antioxidants (stabilizers, anti-aging additives)

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

OHC(CH3)3(H3C)3C

CH2 CH2 C

O

O

CR

R,RR

R =

Irganox 1010

OHC(CH3)3(H3C)3C

CH2 CH2 C

O

O C18H37

Irganox 1076

A B C D0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

Mig

rate

d am

ount

( µg/

dm2 )

water skimmilk

chickenbroth

vegetableoil

Irganox 1076 (polypropylene, 1.5 h, 135 0С)Irganox 1010 (low-density polyethylene, 1.5 h, 95 0С)Irganox 1010 (polypropylene, 1.5 h, 100 0С)

A B C D0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

Mig

rate

d am

ount

( µg/

dm2 )

water skimmilk

chickenbroth

vegetableoil

Irganox 1076 (polypropylene, 1.5 h, 135 0С)Irganox 1010 (low-density polyethylene, 1.5 h, 95 0С)Irganox 1010 (polypropylene, 1.5 h, 100 0С)



Plasticizers

Compound that is added to the polymer for facilitating its processing

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

COCH2CH(CH2)3CH3

COCH2CH(CH2)3CH3

O

O

C2H5

C2H5di-2-ethyl hexyl phthalate or dioctyl phthalate

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.

!

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



The copolymers of poly(vinyl chloride) and poly(vinylidene chloride) are plasticized with up to 5% of acetyltributyl citrate.

ca. 90% of all plasticizers are used with PVC

Migration of acetyltributyl citrate into microwave-cooked foodsMigration of acetyltributyl citrate into microwave-cooked foods

CH3 (CH2)3 O CO CH2 C CH2

CO

OCOCH3

CO O (CH2)3 CH3

O (CH2)3 CH3


additives included in the packaging Other types of additives

antistatic agents

“antifog” agents

antiblocking agents

dyes and pigments

foaming or blowing agents

ethoxylated fatty acid, polyhydrated alcohols, non-ionogenic substances that contain quaternized ammonium groups

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)



CH CH2

The monomers are much more toxic than the corresponding polymers

styrene

It has been found that the migration of styrene from polystyrene cups containing hot or cold drink is about 0.025% per cup.

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

!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 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)

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

!



CH2 CHCl

vinyl chloride

highly toxic substance - its levels in poly(vinyl chloride) food packaging materials are controlled extremely strictly

Any package that contains 275 ppb residual vinyl chloridecannot be used for food applications!!!

CH2 CHCN

acrylonitrile

!

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.


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.

!

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

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

Polymeric materials from synthetic and natural polymers for food packaging and food

preservationLeonardoLeonardo dada Vinci IIVinci II

PilotPilot projectproject

N. Manolova, O. Stoilova, D. Paneva, I. Rashkov

Bulgarian Academy of SciencesInstitute of Polymers

www.e-fost.org

Acknowledgments:

Grant ТК CH 1605 Novel functional nanostructured materials for

electrochemical detection of pesticides in foods

THANK YOU FOR THE ATTENTION!THANK YOU FOR THE ATTENTION!

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Polymer Packaging and Food PP

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