MIGRANTS FROM FOOD CONTACT MATERIALS

Transcription

1 MIGRANTS FROM FOOD CONTACT MATERIALS Prof. Sonja Srbinovska Faculty of Agricultural Science and Food, Ss. Cyril and Methodius University in Skopje Eco-sustainable food packaging based on polymer nanomaterials COST ACTION FA0904

2 Food during its manufacture, transport, storage, preparation and consumption materials used to construct storage vessels, conveyor belts, tubing, food preparation surfaces, cooking and eating utensils. PACKAGING MATERIAL

3 DEFINITION Food contact materials are materials and articles intended to come into contact with foods such as: Packaging materials; Cutlery and dishes; Processing machines; Containers;

4 PACKAGING IS BENEFICIAL. It protects the packaged foodstuff from spoilage by external agents such as pests, odours, micro-organisms, light and oxygen. However, the transfer of chemicals from packaging to food may have a negative impact on the quality and safety of food. This is why migration from packaging and other food contact materials merits study, consideration and control.

5 Packaging is the most important, and certainly the most obvious, example of a material or article intended to come into contact with food. Food and beverages can be very aggressive products and may interact strongly with materials that they touch. Collectively, they are as good as many of the solvents used in a chemistry laboratory. For example, food acids can corrode metals, fats and oils can swell and leach plastics, beverages can disintegrate unprotected paper and cartonboard

6 o No food contact material is completely inert and so it is possible for their chemical constituents to migrate into the packaged food. Metals, glass, ceramics, plastics, rubber and paper can all release minute amounts of their chemical constituents when they touch certain types of foods. o This release of chemicals to the food is known technically as migration. o This can be defined scientifically as the mass transfer from an external source into food by submicroscopic processes. o More colloquial terms used are leaching, bleeding or leaking of substances from the packaging into the food.

7 The range of materials used in contact with foods Ten main categories: 1. plastics, including varnishes and coatings 2. paper and board 3. metals and alloys 4. glass 5. regenerated cellulose 6. ceramics 7. elastomers and rubbers 8. paraffin waxes and micro-crystalline waxes 9. wood, including cork 10. textile products.

8 Plastics in particular have a dominant position, especially considering that many paper and board packages are laminated to plastics as the food contact surface and most metal cans are lacquered inside with polymeric coatings to protect the metal from the food. Plastics can be regarded as macromolecular organic compounds which can be produced synthetically or by modification of naturally occurring products, like for example regenerated cellulose

9 Various kinds of plastics may be used

10 What are additives? Apart from the fundamental component the polymer plastics contain other chemical components as well. These so-called additives and are added to alter the properties of the polymer in a desired way. Generally these additives are applied in relatively small concentrations, although for example fillers (e.g. silica) and plasticizers (e.g. phthalates) are used at high concentrations as well. Apart from the additives, also processing aids, necessary to the polymerisation process, can be present. Typical examples include: surfactants, initiators, cross linkers, catalysts, etc. In addition to the low molecular weight compounds, residual monomers and oligomers can be present within the plastic material. Finally also impurities, degradation or reaction products of plastic ingredients were found to be present in polymeric contact materials as well. All these low molecular weight compounds are not covalently bound to the polymer chain, they are able to diffuse throughout the polymer matrix. This diffusion is one of the basic processes of the migration from plastic food contact materials.

11 What are additives? (2) Legislative definition on additives in plastic Additive: Substances which are incorporated into plastics to achieve a technical effect in the finished product, including polymeric additives. They are intended to be present in the finished articles. Substances used to provide a suitable medium in which polymerization occurs. Polymerization production aids (PPAs) are not intended to remain in the finished article The additive list does not include: (a) Aids to polymerization: the substances which directly influence formation of polymers (catalysts, initiators etc); (b) colorants; (c) solvents. the

12 What are additives? (3) Polymeric additives Any polymer and/or prepolymer and/or oligomer which may be added to plastics in order to achieve a technical effect but which cannot be used in absence of other polymers as the main structural component of finished materials and articles. It includes also substances which may be added to the medium in which polymerization occurs.

13 must be safe

14 The main additives used in plastic manufacture together with their function. Additive Function 1. nucleating agents induce regular crystallisation 2. lubricants improve processing above glass transition temperature, alters rheology 3. antistatic agents reduce the chargeability of the plastic 4. blowing agents generate inert gases to produce expanded plastics 5. plasticizers gel the polymer, improve flexibility and processibility 6. antifogging agents avoid water droplets on films used to pack moisture rich foods 7. dyes and pigments impart colour of the plastic 8. fillers and reinforcing agents increase bulk and improve physical properties 9. stabilizers 9.1. antioxidants avoid polymer oxidation by trapping free radicals or by inducing decomposition of peroxides 9.2. UV absorbers reduce harmful effect of UV radiation 9.3. heat stabilizers prevent dehydrochlorination during processing of PVC 9.4. anti-acids neutralise acids arising from catalysts or PVC thermo degradation

15 Materials other than plastic Glass has been used for many years may result in leaching of lead. Ceramics may result in leaching of heavy metals particularly when in contact with acidic beverages like fruit juices. Cans food packed in tin cans with lead soldered - seams are a source of a number of metals, including lead, chromium, tin and cadmium.

16 FOOD PACKAGING Packaging innovation - to ensure food safety as certain components of packing like printing inks, labels, colours, seals can affect food quality. Innovative packaging like vaccum packaging, controlled atmosphere or modified atmospheric packaging (CAP or MAP). MAP involves sealing package under vaccum or one time gas flushing and sealing. Three types of gases may be used singly or in combination namely nitrogen, carbondioxide and oxygen.

17 Active Packaging Includes additives capable of scavenging or absorbing oxygen, CO2, ethylene, moisture, odour and flavours. May have powder sachet of iron and calcium hydroxide. Definition of active packaging Materials and articles intended to extend the shelf life or maintain or improve the conditions of the packaged food Designed to deliberately incorporate components that release or absorb substances from or into the packaged food or its surrounding environment

18 Intelligent Packaging Provides way to monitor and relay information regarding the status of contents and verifies information. Food packaging manufacturers have developed several innovative intelligent packages that include time, temperature indicators, antitheft and use RFID devices. Definition: Materials and articles which monitor the conditions of the packaged food or the surrounding of the food (Framework Regulation (EC) 1935/2004) => can be in contact with food or not in contact with food

19 Adjusting the Packaging Active and Intelligent materials Attach labels to monitor content Add quality improving substances Remove unwanted substances Add antimicrobials Improve barrier properties Include oxygen reacting layer Use nanomaterials

20 Active Packaging H 2 S, NH 3 and ethylene scavenger Oxygen scavenger in sachet Oxygen scavenger label ethylene scavenger

21 Effect of ethylene absorber Carrot Bananas Storage for 21 days without and with ethylene absorber (based on potassium permanganate coated zeolite in a tyvek sachet) Source:

22 Commercial timetemperature indicators Intelligent Packaging

23 Application of Nanotechnology in Food Contact Materials Incorporate NPs into shaped objects and films to improve: durability optical and barrier properties resistance to temperature and flame Nanomaterials The food contact legislation does not address nanomaterials specifically Basic principle remain: food contact material - must be safe A nanomaterial made from ingredients listed on positive may not covered by the legislation Enjoy a lot of attention, both from the development side as well as the risk assessment side Case-by-case approach needed EFSA Scientific Committee Guidance on the risk assessment of the application of nanoscience and nanotechnologies in the food and feed chain (EFSA Journal 2011;9(5):2140)

24 Examples of nanofood contact materials available in market Polyethylene terephthalate (PET) bottle Polypropylene container Plastic wrap

25 Examples of nanofood contact materials available in market Lighter and stronger Minimizes loss of CO 2 from Beer Nano food-packaging film (Bayer Polymer Inc) Nanoclay particle based Beer Bottle (Nanocor Inc)

26 The Chemicals Food Contact Materials Substances present in food contact materials may originate from a number of sources: known ingredients used to make the basic packaging materials of plastics, paper, coated and uncoated metals, and glass, for example, monomers and additives in plastics, chemicals used in paper-making, pigments used on ceramics chemicals used to convert or fabricate the basic packaging material into its finished form, for example, inks and adhesives known or unknown isomers, impurities and transformation products of these known ingredients unknown contaminants in the raw materials used, and especially those in the feedstock if materials are recycled. Unexpected or unknown substances originating from the last two categories in this list are what have become known as NIAS (Not Intentionally Added Substances). These can be a particular challenge to industry and enforcement authorities alike.

27 Migration from food contact materials In a food packaging system, three phases should be considered : the food, the package and the environment. In between these phases interactions may occur, resulting in an energy or a mass transfer. The sub microscopic mass transfer involves the diffusion of individual molecules in one phase and their sorption by the other. If the mass transfer involves the three phases of the packaging system, volatiles are transported from the environment via the contact material to the food or vice versa. This phenomenon is known as permeation. No net uptake or removal of chemical substances from the food contact material takes place. The permeation process may significantly affect the quality of the food. Mild preservation techniques such as modified atmosphere packaging, which are used successfully to prolong the shelf life of minimally processed foods, are based on the selective permeation of particular gasses through the packaging material.

28 Migration from food contact materials If mass transfer is restricted only to the food and the packaging material, the phenomenon is also known as migration. Migration can take place from the contact material to the food and vice versa. A typical example of negative migration is the flavour scalping in fruit juices due to the partial absorption of flavour compounds by the plastic contact material. Due to this phenomenon the fruit juice aroma deteriorates. Another example resulting however in an improvement of food quality, is the use of oxygen scavenging materials in the packaging of foodstuffs sensitive to oxidation.

29 Migration The mass transfer from the packaging material to the food can have both deteriorating and improving consequences for the food. Migration of toxic packaging compounds to the food is a serious risk to food safety. Similarly, migration of particular substances could induce sensorial deterioration of the food (e.g. styrene migration). On the other hand, migration of particular food additives such as antioxidants and anti-microbial agents, could improve the shelf life of the product and at the same time minimize the direct use of these additives in the food manufacture.

30

31 Migration from food contact materials Any chemical migration into food is important because it can have two impacts on the food. Food safety some substances used to manufacture packaging materials could be harmful if they migrated to the food and were ingested in large enough quantities. Food quality migrating substances may impart taint or odour to the food and so reduce consumer appeal.

32 Migration from packaging Chemical migration from packaging is not an inconsequential process. It has been estimated that the percapita use of packaging materials for retail foodstuffs sold in the EU countries is about 1200 cm 2 per person per day. This is about the size of two A4 sheets of paper and is not an inconsiderable amount. It is also about the area of film used for just two 35 gram packets of potato crisps, for example. With the increasing consumption of snack and take-away foods and moves to smaller pack sizes (with higher surface area to mass ratio) to satisfy smaller households and convenience eating, it seems inevitable that the use of packaging materials in contact with our diet will continue to increase.

33 Chemical migration For some food package combinations the concentration of chemical migrants in the food can approach that of substances used as direct food additives, at levels of tens of parts-per-million (mg substance per kg of food, mg/kg). Therefore, all parties involved in the production, transport, selling and consumption of foods need to be aware of the potential for chemical migration and ways of minimising it.

34 AWARENESS Everyone involved needs to ensure that packaging materials are correctly specified and used for the intended application so that there is no excessive chemical migration. The chain of care involves: primary manufacturers of raw materials, e.g., polymer and paper manufacturers converters who turn the raw material into packaging for food use vendors of the materials, e.g., retailers of articles, supply companies users of the material the food packer food retailers enforcement authorities consumers with respect to the proper use both of pre-packaged foods and of materials and articles used in the home. The correct specification and use of packaging materials requires effective exchange of information up and down this chain of use. It also requires an understanding of chemical migration and the main factors that control it.

35 Food contact materials Determine safety and suitability of food packaging materials for human use Safety assessment of food packaging material requires knowledge of chemical toxicity, migration and technological developments. Development and harmonisation of experimental approaches to produce reliable data for risk assessment, as well as the monitoring of target contaminants at European level packaging material, the food matrix after migration, or medium used as food simulant

36 In order to ensure consumer protection, legislation has been developed through the years in various countries with regard to food contact materials in general and plastic food contact materials in particular.

37 Framework Regulation (EC) No 1935/2004 GENERAL REQUIREMENTS Safety no change in characteristics of food taste odour composition AUTHORISATION procedure for substances processes final products in a positive list LABELLING AND DECLARATION OF COMPLIANCE Positive labelling for all empty food contact materials not clearly intended to come into contact with foodstuffs + symbol Declaration of compliance shall be supported by appropriate documentation to be available to competent authorities on demand ( record keeping ) TRACEABILITY at all stages of manufacture, processing and distribution responsibility one step above and below in supply chain make information available to competent authorities traceable through labelling or documentation

38 Legislation on specific materials Ceramics Directive 84/500/EEC : Sets migration limits for cadmium and lead which might be released from decoration and/or glazing; Gives the analytical method determining the migration of these substances. Regenerated cellulose film Directive 2007/42/EC : Lists authorised substances and conditions for their use; Includes provisions for plastic coated regenerated cellulose film.

39 Legislation on specific materials Recycled plastic materials Regulation EC 282/2008: Sets requirements for recycled plastics to be used in food contact materials; and Introduces an authorisation procedure of recycling processes used in the manufacture of recycled plastics for food contact use. Active and intelligent materials and articles Regulation EC 450/2009: Adds requirements to Regulation EC 1935/2004 for their safe use; Introduces an authorisation scheme for substances used for active and intelligent functions in food contact materials.

40 Legislation on specific materials Plastics As of 1 May 2011, Regulation EU/10/2011sets the rules for plastic food contact materials are regulated by consolidating 14 directives of EU regulation on plastics. What does the Regulation cover? Printed or coated plastic materials and articles; Printed or coated plastic multi-layer materials and articles held together by adhesives or other; Plastic layers or coatings forming gaskets in caps and closures that make a set of 2 or more layers of different types of materials; Plastic layers in multi-material, multi-layer materials and articles.

41 Regulation EU/10/2011 What rules does the Regulation set? List of authorised monomers and additives for use in plastics manufacture; Restrictions and specification for authorised substances including specific migration limits; Rules on non-intentionally added substances i.e. impurities and reaction products; Overall migration limit; Rules on compliance especially migration testing, listing simulants, testing conditions; The concept of functional barrier; Authorisation for nano-materials before use; Declaration of compliance and supporting documentation.

42 Thank you for your attention