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PLASTICS IN FOOD PACKAGING

RECYCLING OF PLASTICS IN FOOD PACKAGING

Chapter 14RECYCLING OF PLASTICS

IN FOOD PACKAGING

Baldev Raj

Food Packaging Technology DepartmentCentral Food Technological Research Institute

Mysore 570 020 (INDIA)

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RECYCLING OF PLASTICSIN FOOD PACKAGING

lastics are used world over because theyare safe for packaging of foods, medicinesand child care products. A few examplesare - milk pouches, edible oil containers,ice-cream packs, blister packs for tabletsand capsules and I.V. fluids. Blood iscollected and stored in plastic bags. Plasticwoven sacks made of HDPE and PP arealso used for transportation, storage anddistribution of grains and sugar. Whileplastics are safe for packaging of food andmedicinal products, there are standards ineach country, which specify the type ofadditives and pigments, which can beused safely for contact with foods. Recentdevelopments in plastics technology haveled to stronger materials so that lessmaterial is needed for particular appli-cations. Plastics packaging achievesmaximum mileage from minimumresources and is therefore an excellentmeans of conserving natural resources.Plastic waste is predominantly eco-neutralor inert. It does not generate toxic leachates,which contaminate the soil or groundwater resources. On the contrary, thoseproducts, which biodegrade with by-products, may result in contaminatingground water resources. Plastic consumerwaste is easily compactable, and occupies

less space in land-fills. The fact that plasticwaste is inert and does not biodegrade,makes segregation and recycling a morelogical approach to waste management, forurban areas. That plastics, mostly as carrybags, form the most formidable threat topublic spaces is being realized. Cityadministrations also know the futility ofbanning their use. One promising solutionto the problem is shredding plastic waste,mixing it with bitumen and using thepolymerized mix in road construction.Therefore, it is logical to infer that plastics,as such do not create any sort of pollutionto pose any threat to environment. It isonly a waste management issue.

Plastics and the Environment

It is estimated that India generates 5,600tonnes of plastic waste daily. That is boundto grow. It is reassuring that inventiveminds all over India are working to turn ahuge problem into an advantage � hope-fully one that doesn�t compromise withrespect to the environmental concerns.

Plastics as a whole are being lookeddown upon as environment unfriendly. Butthis is not true. The problem with plasticsis their waste disposal management. The

P

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Ministry of Environment & Forests,Government of India, has in consultationwith members of the Plastic Industry afterdetailed study, worked out a way to mini-mize the effects of plastic waste. The Plasticindustry has agreed to honour the nationalguidelines on waste management.

Plastics make a significant contributionby reducing the weight and volume ofmaterials that are typically thrown away.Unfortunately in India, waste is littered,instead of being disposed to facilitatecollection and recycling. Plastics use lessthan 4% of the world�s hydrocarbonresources. While about 90% is consumedfor transportation, power generation andheating. In general, plastic productsrequire less energy than products madefrom conventional materials, at compa-rable use and performance levels. Everyprocess connected with a product, rightfrom the time that basic raw materials areextracted from the earth to the time aproduct is produced, transported, used anddisposed, has some impact on theenvironment.

Recycling of Plastics

All plastics can be recycled. Morethan 90% of manufacturing off-cuts andout-of-dimension products are reprocessedinto primary products. Fortunately in ourcountry, plastic re-cycling is absolutelyeconomy driven, and does not need anysubsidy. Unlike paper, textile, wood, etc.,65% of the plastics waste is recycled inour country, which is much higher incomparison to, advanced countries. It notonly enables poor people to buy items madeof recycled plastic at affordable prices, butalso provides employment to millions ofpeople in our country.

Recycling of plastics consists of threemain steps - shredding, remelting and re-forming in moulds. The machinery usedconsists of a grinder, an extruder and apelletiser, each of which could cost fromRs 1.5 � 2 lakh. After sorting according tograde, the plastic waste is put into anagglomerator that heats and shreds it intofine flakes (called the �agglu�), which areput into an extruder. Here it is heated,extruded through screens, and solidifiedinto strands by passing it through coldwater. The strands are cut into pellets,which form the raw material for mouldingsheets, tarpaulins, pipes, etc. The processis energy intensive as energy costs makeup two-thirds of the cost of production.

Plastics as a whole are being lookeddown upon as environment unfriendly.But this is not true. The problem withplastic is its waste disposal management.The Ministry of Environment and Forests,Government of India, has in consultationwith members of the plastic industry afterdetailed study, worked out a way tominimize the effects of nuisance of plasticwaste. The Plastic industry has agreed tohonour the national guidelines on WasteManagement. Not all plastics arerecyclable. There are 5 major types ofplastics which are commonly recycled:

l Polyethylene (PE) - both high densityand low density PE and Linear low-density PE.

l Polypropylene (PP)

l Polystyrene (PS)

l Polyvinyl chloride (PVC)

l Polyethylene terephthalate (PET) -others.

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A common problem with recyclingother plastics is that plastics are often madeup of more than one kind of polymer orthere may be some sort of fibre added tothe plastic (a composite) to give addedstrength. This can make recovery difficult.Of the types of plastics recycled in India,PVC (polyvinyl chloride) accounts for 45percent, LDPE (low density polyethylene)for 25 percent, HDPE (high densitypolyethylene) for 20 percent, PP (polypro-pylene) for 7.6 percent and other poly-mers such as PS (polystyrene) for 2.4percent. According to manufacturers,almost all these types of waste can berecycled up to four or five times. However,the quality of the recycled materialdeteriorates and additives or virginmaterial are added to give it strength.

Large scale recycling plants can bescientifically controlled with highstandards of Research and Developmentand Quality Control for producing goodquality compounds and recycled endproducts. End products like syntheticwood, benches for parks, public places,railways and airports, fencing for parks,side walks and roads, boundaries andbuildings, sleepers for Railway tracks,pallets for bulk transportation, bodies oftrucks, waste collection dumps, sign boardsand marine transportation are some of thenew markets which will have endlessrequirements of products developed fromsuch plastics waste.

The economics of energy generationand cost of labour for such a wastemanagement organization and hence theend products are favourable indicators forviability and success of this entire wastemanagement system.

In India, success in recycling ofconsumer level plastics is going to begoverned by the profitability of therecycling idea. There are millions of urbanIndians who scour our cities for a livingfrom waste. They play an insufficientlycelebrated role in waste management.

Waste �picking� is a well-establishedurban survival tactic in India�s mega-cities,those metropolises that act as magnets forthe poorest of the population, and recyclingis a flourishing business in this informalsector. It supports up to 0.5% of thepopulation in cities of over a millioninhabitants, and saves a city 10-15% of itstotal waste management costs throughreduction in waste volumes. Recyclablewaste is attracting a few service providersonly now in commercial areas. Small-scaleand cottage industry recycling is stillmostly illicit twilight activity, and recyclersoften operate behind closed doors, avoidingregistration.

Only recently has recycling won formallegitimacy in India through the MunicipalSolid Waste (MSW) Rules, which directmunicipalities to �promote recycling orreuse of segregated materials� and �ensurecommunity participation in wastesegregation�. This should improve thestatus and working conditions in thissector, and allow recycling technologies tobe upgraded. India today presents a goldenopportunity for suppliers of all types ofsimple, low-cost recycling processes andequipment.

Classification of Recycling

Plastics recycling technologies havebeen historically divided into four generaltypes - primary, secondary, tertiary andquaternary.

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i. Primary Recycling involvesprocessing of a waste/scrap into a product.The recycling of relatively uncontaminatedwaste plastics, that has historically takenplace in the manufacturing sector, is anexample of primary recycling.

ii. Secondary Recycling involvesprocessing of waste/scrap plastics intomaterials that have characteristics differentfrom those of the original plastics products.Some manufacturing and post consumerwastes currently enter secondary recyclingstreams that allow higher contaminationlevels than primary recycling.

iii. Tertiary Recycling involves theproduction of basic chemicals and fuelsfrom plastics waste/scrap as part of themunicipal waste stream or as a segregatedwaste. Pyrolysis and hydrolysis areexamples of these processes.

iv. Quaternary Recycling retrieves theenergy content of waste/scrap plastics byburning/incineration.

Only primary recycling of post-consumer materials or purchasedindustrial plastics scrap, and secondaryand tertiary plastics recycling reducecurrent waste disposal volumes.Quaternary recycling falls within the term�resource recovery�. Primary recycling ofscrap from in-plant operations is socommonly practised that it is excludedfrom standard recycling definitions.

Processing of Recycling

n Initial upgrading. Once the plastic has

been collected, it will have to be cleanedand sorted. The techniques used willdepend on the scale of operation and thetype of waste collected, but at the simplestlevel, they involve hand washing and

sorting of the plastic into the requiredgroups. More sophisticated mechanicalwashers and solar drying can be used forlarger operations. Sorting of plastics canbe by polymer type (thermoset orthermoplastic for example), by product(bottles, plastic sheeting, etc.), by colour,by coating, etc.

n Size reduction techniques. Size reduction

is required for several reasons: to reducelarger plastic waste to a size manageablefor small machines, to make the materialdenser for storage and transportation, orto produce a product which is suitable forfurther processing. There are severaltechniques commonly used for sizereduction of plastics:

Cutting is usually carried out for initialsize reduction of large objects. It can becarried out with scissors, shears, saw, etc.

Shredding is suitable for smaller pieces.A typical shredder has a series of rotatingblades driven by an electric motor, someform of grid for size grading and acollection bin. Materials are fed into theshredder via a hopper which is sited abovethe blade rotor. The product of shreddingis a pile of coarse irregularly shaped plasticflakes which can then be further processed.

Agglomeration is the process of pre-plasticising soft plastic by heating, rapidcooling to solidify the material and finallycutting into small pieces. This is usuallycarried out in a single machine. Theproduct is coarse, of irregular grain and isoften called crumbs.

Further Processing Techniques

n Extrusion and pelletising. The process ofextrusion is employed to homogenise thereclaimed polymer and produce a material

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that is subsequently easy to work. Thereclaimed polymer pieces are fed into theextruder, heated to induce plasticbehaviour and then forced through a dieto form a plastic spaghetti which can thenbe cooled in a water bath before beingpelletised. The pelletisation process is usedto reduce the �spaghetti� to pellets whichcan then be used for the manufacture ofnew products.

Manufacturing Techniques

n Extrusion. The extrusion process used

for manufacturing new products is similarto that outlined above for the processpreceding pelletisation, except that theproduct is usually in the form of acontinuous �tube� of plastic such as pipingor hose. The reclaimed plastic is forcedalong the heated tube by an archimedesscrew and the plastic polymer is shapedaround a die. The die is designed to givethe required dimensions to the product andcan be interchanged.

n Injection moulding. The first stage of this

manufacturing process is identical to thatof extrusion, but then the plastic polymeremerges through a nozzle into a splitmould. The quantity of polymer beingforced out is carefully controlled, usuallyby moving the screw forward in the heatedbarrel. A series of moulds would be usedto allow continual production whilecooling takes place. This type of productiontechnique is used to produce moulded

products such as plates, bowls, buckets,etc.

n Blow moulding. Again the spiral screw

forces the plasticised polymer through adie. A short piece of tube, or �parison� isthen enclosed between a split die -whichis the final shape of the product - andcompressed air is used to expand theparison until it fills the mould andachieves its required shape. Thismanufacturing technique is used forproducing closed vessels such as bottlesand other containers.

n Film blowing. Film blowing is a process

used to manufacture such items as garbagebags. It is a technically more complexprocess than the others described in thisbrief and requires high quality rawmaterial input. The process involvesblowing compressed air into a thin tube ofpolymer to expand it to the point where itbecomes a thin film tube. One end can thenbe sealed and the bag or sack is formed.Sheet plastic can also be manufacturedusing a variation of the process described.

Coding for Recycling

A coding system has also beenintroduced in the United States to aididentification of plastics for reclamation. Itis based on the �Recycle Triangle� with aseries of numbers and letters to help theidentification.

While marking the symbol 7, the

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respective basic raw materials like ABS,OPP, PC, PBT, etc, or "mixed" shall beindicated below the symbol.

In addition to the symbol indicated, theend product made out of recycled/reprocessed plastics, wherever possible,shall be marked with "Recycled" indicatingpercentage of use of recycled material.

In India, the following informationshould also be printed bilingually,English/Hindi and local languagewherever possible on the end product forthe benefit of users/reprocessors: �Thisproduct (like carry bags/shopping bags,bottles, blow-moulded containers, etc) ismade of (indicate materials) and isreusable/ recyclable�.

However, carry bags/containers made

out of recycled plastics shall be labeled as�Not suitable for packing/storing/carryingfood products�

�Food grade� material, like that usedto make milk bags, is made from virginplastic. Manufacturers emphasize thatbags made from recycled plastic shouldnot be used to store �unpacked� fooditems, as there is a chance of contaminationof food with chemicals.

A CFTRI case Study onRecycled Polyethylene films

A study was conducted at CFTRI,Mysore, on recycled polyethylene materialsusing ICPL FS 300 virgin gradepolyethylene (virgin) and extrusion wasteof virgin grade (A-grade) which wereobtained from an industrial organization,

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reprocessed film from used milk pouches(recycled milk pouches) and waste plasticscollected from different sources (B-grade).These materials were processed at a localreprocessing factory. The recycled filmswere evaluated for physico-chemcialproperties like tensile strength, elongationat break, impact strength, grease resistance,the water vapour transmission rate(WVTR), the oxygen transmission rate, heatseal strength and drop tests. These werecarried out according to specifiedstandards. The processed films were alsostudied for compatibility with foods bycarrying out the migration tests. In general,plastic materials coming in contact withfood were assessed for the extent ofmigration of additives into foods by the�global migration� tests in respective foodsimulants. Since invariably, polyethyleneforms the contact layer with fatty food,global migration was carried out using n-heptane as fat simulant. The total additivespresent in the materials were determinedby �extraction� test with xylene and n-hexane by measuring the maximumextractible fraction of the additives.

The results revealed that there washardly any difference between extrusionwaste recycled polythene film and virginfilm in all the properties. However, recycledfilm made form milk pouches and wasterecycled films had shown significantchanges in physio-chemical properties andmigration tests which were not acceptablefor packaging application. The compati-bility results of these recycled films indi-cated that the migration/extraction valueswere nearly twice in the film extruded frommilk pouch than in virgin film in n-heptaneand comparatively quite higher in othersolvents. The increase in migration and

extraction values is probably due todegradation and improper cleaning ofrecycled materials.

From the studies, it could be inferredthat addition of recycled low-densitypolyethylene will bring down the physico-chemical properties and enhance themigration and extraction values ascompared to the virgin grades. Also, fromthe safety and strength properties pointof view, it is not preferable to add recycledplastic. However, addition of extrusionwaste obtained at the plant itself in certainquantity may not affect the propertiessignificantly.

LEGISLATIONS ONRECYCLED FOODPACKAGING MATERIALS

Different countries are coming up with

polices on recycling of plastics in foodpackaging and to prevent environmentalpollution.

EC Regulations

The European Commission has madeproposals to regulate the use of recycledplastic materials and articles intended tocome into contact with food. The UK FoodStandards Agency has now published aconsultation paper seeking views on theproposals. The Commission�s proposaldeals with mechanical processes forrecycling food contact plastic for furtheruse in contact with food.

Under the proposals, a system will beput in place that will allow a person orcompany to apply for an authorization touse a specified process to recycle foodcontact plastics for further use in contact

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with food. The application will beexamined by the European Food SafetyAuthority before it makes a recommen-dation to the European Commission. TheCommission will then decide whether togrant an authorization, with the intentionof ensuring that the public is protectedfrom unsafe contaminants in the recycledplastic.

At the moment, there is no harmonizedsystem in place across the EU forregulating the recycling of food contactplastics. Therefore, the Food StandardsAgency proposes to support the intentionto make harmonized rules that will applyacross the EU, subject to ensuring that theyprovide a good framework that allowsbusinesses to operate within a system thatprovides effective protection to consumers.

US-FDA

There is an emphasis throughout theUnited States on increasing the uses ofrecycled materials, including plastic. FDAis involved when industry collects usedpolymeric materials (usually, foodcontainers) and proposes to recycle thesematerials to make new food containers.FDA�s main safety concerns with the useof recycled plastic materials in food-contactarticles are:

1) that contaminants from the postconsumer material may appear in thefinal food-contact product made fromthe recycled material,

2) that recycled post-consumer materialnot regulated for food-contact use maybe incorporated into food-contactpackaging, and

3) that adjuvants in the recycled plasticmay not comply with the regulationsfor food-contact use.

Currently, to address these concerns,FDA considers each proposed use ofrecycled plastic on a case-by-case basisand issues informal advice as to whetherthe recycling process is expected toproduce plastic suitable for food-contactapplications. FDA has prepared adocument entitled Points to Consider for theUse of Recycled Plastics in Food Packaging:Chemistry Considerations that will assistmanufacturers of food packaging inevaluating processes for recycling plasticinto food packaging.

If a manufacturer would like FDA toconsider the use of recycled plastic for afood-contact application, the followinginformation should be submitted:

1. A complete description of the recyclingprocess, including a description of thesource of the recyclable plastic and adescription of any source controls inplace intended to ensure that onlyplastic that initially complied with theapplicable regulations is recycled.Also, a description of any steps thatare taken to ensure that the recyclableplastic is not contaminated at somepoint, either before collection forrecycling, or during the recyclingprocess.

2. The results of any tests performed toshow that the recycling processremoves possible contaminants. Foruse of the recycled material as asubstitute for plastic made from virginmaterials, it would be necessary toeither show that there has been nopossibility of contamination withsubstances other than food or todemonstrate, through surrogate con-taminant testing and, if appropriate,additional migration testing, that the

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recycling process successfully removespossible contaminants. However,surrogate contaminant testing is nolonger considered necessary todemonstrate that post-consumerrecycled (PCR) polyethyleneterephthalate (PET) or polyethylenenaphthalate (PEN) produced by atertiary recycling process is suitable forfood-contact use. Because FDA hasdetermined that tertiary recyclingprocesses produce PCR-PET or PEN ofsuitable purity for food-contact use, theAgency no longer sees a need toevaluate tertiary recycling processes forPET or PEN or to issue individualopinion letters for them.

3. A description of the proposedconditions of use of the plastic (e.g.,information on intended temperatureof use, type of food with which theplastic will come into contact, theduration of the contact, and whetherthe food-contact plastic will be forrepeated or single-use applications.)

AUSTRALIA

Relatively little work has been done todetermine what chemical changes occurwhen plastic and paper materials arerecycled.

Recycling of in-house scrap materialshas been practised by the packagingindustry for many years. Such materialspresent no potential hazard because theyhave never been used as packaging.

However, the use of recycled packagingmaterials other than metals and glass, afterthe consumer has used them, is potentiallya problem because of contamination froma variety of sources. Since there are no

controls on the treatment procedures orthe uses to which these materials havebeen put, there is no control over the typeof contaminants which may be present.

The adoption of a Code of Practice bythe packaging industry would be the mostappropriate way to deal with the use ofrecycled materials in any form ofpackaging. This would also requireresearch to establish the potential dangers,and provide means for their elimination.

It is inevitable that some recycledmaterials would not be acceptable for usein many food packaging applications.

The National Food Authority ismonitoring discussions between CSIROand parts of the packaging industry onthe potential application of recycledpackaging materials in the packaging offoods. The Authority, through the foodregulations, has the role of determiningwhen and how recycled materials couldbe used.

Consumers should be aware thatrecycled materials are second-hand.Products packaged in recycled packagingmaterials should be labelled as such. Thisis especially important with importedpackaging materials and foods packagedin imported materials. The public shouldbe conscious that there are potentialproblems especially since the EuropeanEconomic Community seems to havestarted exporting used packaging materialsto developing countries following theintroduction of regulations designed toreduce land fill demand in Europe.

THE GAZETTE OF INDIA

The Central Government has notifiedthe rules for the manufacture and use

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of recycled plastics carry bags andcontainers:

1. Prohibition of usage of carry bags orcontainers made of recycled plastics� No vendor shall use carry bags orcontainers made of recycled plasticsfor storing, carrying, dispensing, orpackaging of foodstuffs.

2. Conditions of manufacture of carrybags and containers, made of plastics� Subject to the provisions of rule 4,any person may manufacture carrybags or containers made of plastics ifthe following conditions are satisfied,namely-

(a) Carry bags and containers madeof virgin plastic shall be in naturalshade or white;

(b) Carry bags and containers madeof recycled plastic and used forpurposes other than storing andpackaging foodstuffs shall bemanufactured using pigments andcolourants as per IS: 9833-1981entitled �List of pigments andcolourants for use in plastics incontact with foodstuffs, pharma-ceuticals and drinking water�.

3. Recycling � Recycling of plasticsshall be undertaken strictly inaccordance with the Bureau of IndianStandards specification: IS 14534: 1998entitled �The Guidelines for Recyclingof Plastics�.

4. Marking/codification � Manufactu-rers of recycled plastic carry bagshaving printing facilities shall code/mark carry bags and containers as perBureau of Indian Standards Speci-fication: IS 14534: 1998 and the end

product made out of recycled plasticsshall be marked as �recycled� alongwith the indication of the percentageof use of recycled material. Othermanufacturers, who do not haveprinting facilities, shall comply withthe condition within one year of publi-cation of these rules. Manufacturersshall print on each packet of carrybag as to whether these are made of�recycled material� or of �virginplastic�.

5. Thickness of carry bags � The mini-mum thickness of carry bags made ofvirgin plastics or recycled plasticsshall not be less than 20 microns.

BIBLIOGRAPHY

Baldev Raj, Vijayalakshmi NS and Ravi P(1992). Problems of plastic contami-nation in foods. Packaging India, 25(2):5-14.

Bergmeyer HU, Brunt E and Lachenicht R(1974). Alkaline phosphatase in serum.In: Methods of Enzymatic Analysis Vol.2, ed: H. V. Bergmeyer. Academic Press,New York, pp. 864-866.

Bharucha D, Meyer H, Mody A and CarmanRH (1976). Hand book of MedicalLaboratory Techniques. Wesley Press,Mysore, pp 53-59.

BIS (1998). IS: 9845. Methods of analysisfor determination of specific and /overall migration of constituents ofplastic materials and articles intendedto come into contact with food stuffs.Bureau of Indian Standards, New Delhi.

CIPET (1997). Proceedings of nationalseminar on recycling and plastics wastemanagement CIPET, Chennai, India.

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Clesceri LS, Greenberg AE and Trussell RH(1989). Standard methods forexamination of water and wastewater.17th ed. APHA, Washington.

Code of Federal Regulations (2001) Food &Drugs. Part 21.171-199.

EEC directive 90/128/EEC (1990) relatingto plastic materials intended to comeinto contact with food stuffs. OfficialJournal of European Communities No.L 75 of 21st March1990.

Kumar KR, Baldev Raj and Balasubrah-manyam N (1993). Changes in pro-perties of recycled polyethylenes.Deutsche Lebensmittel-Rundschau,89(12): 386-388.

Lillie RD (1965). In: Histopathologi-cal Techniques and Practical Histo-chemsitry. McGraw Hill. New York,pp. 176-177.

Murthy RAN, Baldev Raj, Vijayalakshmi,NS and Veerraju P (1990). Effect ofvolume of food simulating solvents inmigration tests. Deutsche Labensmittel-Rundschau, 86:12.

Reitman S and Frankel S (1957). A colori-metric method for determination ofserum glutamic oxaloacetic and gulta-mic pyruvic transaminases. AmericanJ Clin Pathology, 28: 56-63.

Vijayalakshmi NS, Baldev Raj, MurthyRAN and Raju PV (1992). Effect of oneside and two side exposure of plainfilms on the amount of extractives infood simulatnts in migrtion tests.Deutsche Lebensmittel Rundschau, 88:154-156.

Zimmerman HJ and Weinstein BS (1956).Lactate dehydrogenase activity inhuman serum. J Lab Clin Med, 48: 607-612.

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APPENDIXABBREVIATIONS USED FOR PACKAGING MATERIALS

Abbreviations Materials

PE Polyethylene

LDPE Low density polyethylene

LLDPE Linear low density polyethylene

MDPE Medium density polyethylene

HDPE High density polyethylene

HMHDPE High molecular high density polyethylene

PET Polyethylene terephthalate (Polyester)

KPET PVDC coated polyester

MPET Metallised polyester

PP Polypropylene

CPP Cast polypropylene

OPP Oriented polypropylene

MOPP Metallised oriented polypropylene

PS Polystyrene

OPS Orientated polystyrene

EPS Expanded polystyrene

SAN Styrene/acrylonitrile copolymer

ABS Acrylonitrile/butadiene/styrene copolymer

PA Polyamide (Nylon)

PVC Polyvinyl chloride

UPVC Unplastisiced polyvinyl chloride

PVDC Polyvinylidene chloride

PVA Polyvinyl acetate (also PVAC)

PVAL Polyvinyl alcohol

CMC Carboxymethyl cellulose

CA Cellulose acetate

EVA Ethylene/vinyl acetate

TPX Pentene polymer

CAB Cellulose acetate butyrate

EC Ethylic cellulose

EVOH Ethylene vinyl alcohol

B Bonding agent

ION Ionomer (Surlyn)

MXXT Cellophane

FRP Fibre reinforced plastics

PC Polycarbonate

Foil Aluminium foil

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