Food grade packaging regulations

47

PLASTICS IN FOOD PACKAGING

FOOD GRADE QUALITY OF PLASTICS AND REGULATIONS

Chapter 3

FOOD GRADE QUALITYOF PLASTICS AND

REGULATIONS

Baldev Raj

Food Packaging Technology DepartmentCentral Food Technological Research Institute

Mysore 570 020 (INDIA)

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Chapter 3

49



Chapter 3

FOOD GRADE QUALITY OFPLASTICS AND REGULATIONS

ROLE OF ADDITIVES INPLASTICS

In addition to the basic polymers, plasticsalso contain additional chemical compo-nents called additives, which are added insmall amounts to alter the properties of thepolymers in the desired way and/or simplifytheir processing. Only fillers and softeners(plasticizers) are used at high concentrationto increase volume and/or weight to improvesoftening, flexibility, elasticity, malleabilityand processability. Other additives aremostly low molecular weight componentslike stabilizers, anti-oxidants, antistaticagents, light stabilizers (UV absorbers),lubricants (slip agents), optical brighteners,etc. Polymer packaging materials may alsocontain small quantities of monomers,oligomers as well as polymerization catalystsand regulators, cross-linking agents,emulsifer agents, etc. These additives alongwith low molecular weight non-polymericcomponents, which occur from plasticpackaging materials, possess high mobility.It is likely that some transfer of low-molecularweight non-polymeric components willoccur from the plastic packaging materialinto the packaged content, therebycontaminating the product with the risk of

toxic hazard to the consumer. However, it isto be remembered that useful properties ofthe plastics are not manifested without theaddition of these additives. Therefore,guidelines for proper use of plastics for foodpackaging applications have beenformulated all over the world, which arenecessary to safeguard health of theconsumer.

Concern over the safety-in-use of plasticsas food packaging materials arisesprincipally from the possible toxicity of otherlow molecular weight constituents that maybe present in the package and hence, getleached into the foodstuff during storage. Asstated above, such constituents arise fromtwo sources:

Polymerisation residues includingmonomers, oligomers (with a molecularweight up to about 200), catalysts (mainlymetallic salts and organic peroxides),solvents, emulsifiers and wetting agents, rawmaterial impurities, plant contaminants,inhibitors, decomposition and side reactionproducts.

The more volatile gaseous monomers,such as ethylene, propylene and vinylchloride, usually fall in concentration with

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Chapter 3

time, but very low levels may persist in thefinished product almost indefinitely. Styreneand acrylonitrile residues are more difficultto remove.

Processing aids such as antioxidants,antiblock agents, antistatic agents, heat andlight stabilizers, plasticisers, lubricants andslip agents, pigments, fillers, mould releaseagents and fungicides are added to assistproduction processes or to enhance theproperties and stability of the final product.They may be present in amounts varyingfrom only a few parts per million up toseveral parts per cent.

Since compounds of the first group arepresent inadvertently, there is not much thatcan be done to remove them. However, theefforts made by the industry to reduce vinylchloride monomer levels in particular,illustrates the advantages of optimummanufacturing processes on the purity ofthe final product. Chemicals added delibe-rately during formulation to alter theprocessing, mechanical or other propertiesof the polymer are likely to be present ingreater amounts than polymerizationresidues and should be subjected to strictquality control. They are normally restrictedto compounds appearing on an approvedlist for food contact use. A brief account ofthe functions of some major additives ispresented below:

Antiblock Agents

These are added to roughen the surfaceof thin films and, hence, prevent themsticking together during machine processing.Silica is most commonly used because itspoor solubility in most polymers helps toincrease the surface concentration and sointroduces irregularity. Similarly, slipadditives such as fatty acids and amides areused to reduce mobility.

Antioxidants

These prevent degradation of the polymerby reacting with atmospheric oxygen duringmoulding operations at high temperaturesor when used in contact with hot foods andto prevent deterioration during storage. Deri-vatives of phenols and organic sulphidesare the most frequently used antioxidants.Some of these compounds are classified asheat stabilizers.

Antistatic Agents

Since all plastics are good electricalinsulators (and are in fact used on a largescale for this purpose) they will retainelectrostatic charges produced by frictionfrom contact with processing machinery.Accumulation of static electricity can causeproblems through the pick-up of dust,adhesion between layers or particles ofplastics, sparking, electrical shock andpossibly fire hazards. Most antistatic agentsare glycol derivatives or quaternary ammo-nium compounds; both increase the electricalconductivity and plate-out onto the surfaceof plastic.

Lubricants

These are added to reduce frictionalforces and are usually low to mediummolecular weight hydrocarbons. Theyshould possess good solubility with theplastic, low volatility and be relatively stablecompounds.

Plasticizers

These are added to make the productmore flexible and less brittle. They are usuallyhigh molecular weight esters. The plasticizeralso gives the material the limp and tackyqualities found in �cling� films. About 80%of all plasticizers are used in PVC. Typically

51



phthalic esters such as dioctyl phthalate(DOP), also known as di-2-ethylhexyladipate(DEHA) are used as plasticizers.

UV Stabilizers

These are needed to protect the productfrom deterioration by sunlight or evensupermarket lighting. Products containingvitamin C are particularly susceptible to thisform of deterioration.

Optical Property Modifiers

The optical properties of a material froma technological aspect are normally describedin terms of their ability to transmit light, toexhibit colour and reflect light from thesurface (i.e, gloss). The majority of foodpackaging films are unpigmented, but someare coloured by the addition of colorants.The principal pigments used as colourantsin packaging are carbon black, whitetitanium dioxide, red iron oxide, yellowcadmium sulfide, molybdate orange,ultramarine blue, blue ferric ammonium ferricammonium, ferrocyanide, chrome green, andblue and green copper phthalocyanines.

Fire Retardants

Although most packaging materials arecombustible, their lack of flame resistance isdisregarded in most food packagingapplications. For example, thermoformedpolystyrene cups and plates are combus-tible; the risk of fire must be balanced againstthe possible toxicity of flame retardantadditives.

Foaming Agents

Foaming or blowing agents are used forthe production of cellular products and arenormally classified into physical andchemical types, according to whether thegeneration of gases to produce the cells takes

place through a physical transition i.e.evaporation or sublimation or by a chemicalprocess i.e. decomposition reactions whichresult in evolution of gases. In food packagingapplications, physical blowing agents arenormally used. For example, expanded andextruded polystyrene foams use a fluoro-carbon or light aliphatic hydrocarbon suchas pentane as the blowing agent.

Antimicrobial Agents

Antimicrobials such as algicides,bactericides and fungicides can be added topolymers to prevent the growth of micro-organisms. However, their use in foodpackaging is rare because of the possibilityof migration into the food itself.

MIGRATION OF ADDITIVES

The ingredients in the plastics packagingmaterials may cause toxicity as a result oftheir migration to the foodstuffs in which thelatter are packed. Therefore, positive lists ofconstituents (additives) to be used inrespective plastics in contact with foodstuffs,pharmaceuticals and drinking water havebeen specified. The manufacturer has tofollow a Good Manufacturing Practice(GMP) using only those additives listed inthe positive list. Prior to categorizing anyplastics as toxic, evidence regarding degreeof migration of their constituents has to beascertained. In general, migration andextraction studies need to be simultaneouslyconducted on actual foodstuffs underconditions, which are slightly more stringentthan those encountered in normal usage. Itis, however, not always possible to analyseactual foodstuffs for the nature and quantityof migrants from the plastics. In order tosimplify such assessment, food simulants/extractants have to be substituted for theactual foodstuffs. Further, it is also very

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Chapter 3

difficult to estimate all the migrantsindividually. Hence, as a good measure, theoverall migration of all the migrants puttogether is considered for safe use, unlessthey are especially toxic and their limits arefixed.

Migration Model

The extent of migration of a substancedepends on its concentration in the material,the extent to which it is bound or mobilewithin the matrix of the material, the thicknessof the packaging material, the nature of thefood with which the material is in contact(dry, aqueous, fatty, acidic, alcoholic), thesolubility of the substance in the food, theduration of contact and temperature.

In a system of polymer/food as presentedin the figure below, we have the food on theleft which can migrate into the polymer layerson the right side, along with an intermediatelayer of swollen polymer with a profile of themigrating food component. On the otherhand, we have a concentration gradient ofthe considered additives, where we assumethat we have a certain diffusion in theundisturbed polymer layer and a muchimproved mobility of the additive in theswollen layer and concentration jump at theinterfaces.

Rudolph particularly considered theconsequence of the model. The followinggeneral formula relates the migration of anadditive. In a system where a cut of theplastic P into a food F at a certain time t, iskept at constant temperature, the modelpredicts direct proportionality of migrationof the concentration CP

A of the considered

additive in the polymer and to the squareroot of time (t).

MFA (T) = α CP

A √t

MFA (T) is concentration of migrating

additive A into test food F, at a temperatureT and α is is a proportionality constant.

where, CA

F is concentration of additivesin food

CF

P is concentration of food inpolymer

CA

P+F is concentration of additive inpolymer and food, which haspenetrated into polymer.

CA

P is concentration of additive inpolymer

INDIAN STANDARDS FOROVERALL MIGRATION(IS: 9845-1998)

CFTRI drafted IS:9845-1998 for �Determi-nation of overall migration of constituents ofplastics materials and articles intended tocome in contact with foodstuffs - method ofanalysis (second-revision)� which is nowimplemented to be followed for overallmigration of plastics constituents for theirfood grade quality in the country. Thisstandard is the result of R & D work on thestudy of various factors affecting themigration of additives in food simulants, inthe laboratory and is at par with otherInternational standards like US-FDA, ECCDirectives, etc. A collection of data regardingthe main composition and overall extractableamount of plastic constituents can help with

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Table 3.1. Classification of foods and selection of simulants

Type Description Examples Simulants

I Aqueous, non acidic Honey, mineral water, sugar �A� (Water)foods (pH>5) without syrups, molasses, skimmedfat. milk, rasgulla, murabba, paste

etc.

II Aqueous, acidic foods Fruit juices, squashes, fruit chunks �B�(pH<5) without fat or puree or paste, vinegar, jams, (3% Acetic

jellies, carbonated beverages, acid)lemonde, processed vegetables,preparation of soups, broths,sauces, RTS beverages, etc.

III Alcoholic beverages: �C1�i) Alcohol concentra- Beer and some pharmaceutical (10% Ethanol)tion less than 10%. syrups. �C2�ii) Alcohol concentra- Wine, brandy, whiskey, arrack (50% Ethanol)tion above 10% and other alcoholic drinks.

IV Oils, fats and processed Vegetable oils, ghee, vanaspati �D�dry foods with surface cocoa butter, lard, dry products (n-Heptane)fat or volatile oils with a surface fat such as biscuits,

spice powder, snacks and savory,chocolate, caramels, malted foodsegg powder, tea coffee powder,confectionery, fried and roastednuts, etc.

V Non-acidic foods Butter, bread, pastry, cakes, milk- �A and D�(pH>5) or high fat and based sweets, ice-cream, moist andhaving high moisture fatty confectionery products.content

VI Acidic foods (pH<5) Pickles, ketchup, cheese, curd, �B and D�or high fat and having fresh and processed meat andhigh moisture content fish products, sauces having fat,

frozen foods, etc.

VII. Dry processed foods Cereals and pulses, dehydrated Only �A�without fat vegetable and fruits, dried yeast,

corn flakes, salt, sugar, milledproducts, barley powder, oats,vermicelli, grain, etc.

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Chapter 3

the estimation of migration. This can be aconsiderable asset to both the producers ofsuch articles and for quality control labo-ratories. Much time and money may also besaved if studies are made on the evaluationof laminates containing layers of recyclingmaterial with unknown impurities whichcan migrate through the virgin plastic layer(functional barrier) in contact with food.

The choice of simulating solvents andtest conditions (time-temperature) dependson the type of foods and conditions of use offood products. Food products have beennow classified into seven major groups asshown in Table 3.1. This table has been pre-pared on the lines of accepted classificationof foodstuffs for such purpose. The table alsogives suitable simulants to be used fordifferent types of foods.

Table 3.2 lists the simulants and testconditions (time-temperature) for extracta-bility studies to be carried out depending onthe type of food and conditions of use.

Selection of Samples

Minimum triplicate samples represen-ting the lot/batch have to be selected.Samples in each replicate shall consist of anumber of containers (preformed orconverted products) with nearest exposedarea of 1,000 cm2. In the case of sealable filmsrepresentative sample shall be of sufficientsize to convert into 2 pouches of size 125 mmwidth and 200 mm length (inner dimensionexcluding seal area) and non-heat sealablefilms of size 50 cm × 10 cm to be exposed overboth the sides with 1,000 cm2 surface areacoming in contact. In case of lids/wads, tenpieces are to be sealed to glass bottles ofsmallest size, in actual use to be placedinverted in position during the test period.

Preparation of Test Specimen

The containers/pouches/film/lids usedshall be carefully rinsed with water (25-30°C) to remove extraneous materials priorto actual migration test.

Simulant Quantity

Equal to nominal filling capacity or atleast 1 ml/cm2 of contact area.

Procedure

Fill the container/pouch to their filledcapacity or non-heat sealable film to beexposed both sides with preheated simulantat test temperature and close it. In case ofpouches, exclude air as much as possiblebefore sealing and expose the filledcontainer/pouch to specified temperaturemaintained in oven/water bath/autoclavefor the specified duration. Remove thecontainer/pouch and transfer the contentsimmediately into a clean Pyrex beaker alongwith three washings of the specimen withsmall quantity of the fresh simulant.

Determination of Amount ofExtractive

Evaporate/distill the contents in Pyrexbeaker/round bottom flask to about 50-60ml and transfer into a clean tared stainlesssteel dish along with 3 washings with smallquantity of fresh simulant and furtherevaporate the concentrate in the dish todryness in an oven at 100±5°C. Cool thedish with extractives in a desiccator for 30minutes and weigh to nearest 0.1 mg tillconstant weight of residue is obtained.Calculate the extractives in mg/dm2

and mg/kg or ml/l or ppm of the foodstuffwith respect to the capacity of container/pouch to be used. Blank shall also be carriedout without the sample for adjustment, ifnecessary.

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Table 3.2. Simulating solvents for different types of foods andtemperature-time conditions

Migration Test Wiw Food simulants-Conditions of use Temperature, Time Conditions (°C)

Water 3% 10% 50% n-Heptane*acetic alcohol alcohol acid

(A) (B) (C1) (C2) (D)

High temperature I, II, 121°C/2h - - 66°C/2hheat sterilized IV, V(Retorting) & VI

Hot filled or I, II 100°C/2h - - 49°C/0.5hpasteurized IV, Vabove 66°C, & VIbelow 100°C

Hot filled or I to 70°C/2h 38°C/0.5hpasteurized IVbelow 66°C

Room tempera- I to 40°C/10 dyas 38°C/0.5hture filled and IVstored and alsoin refrigeratedand frozencondition (nothermal treatmentin container)

Heptane extractivity results must be divided by a factor of five in arriving at the extractivity of a food

product.

Migration Limits

The material shall comply with the overall

migration limit when tested by the method

prescribed in IS: 9845-1998, mg/kg, Max, of

foodstuff. In the case of liquid foodstuffs or

of simulants, the limit shall be 60 mg/l or

ppm., Max. However, the value of the overall

migration limit shall be equal to 10 mg/dm2,

Max, of the surface of the material or article.

In case of lids/wads the results can be

expressed only as mg/kg, 60 mg/l or ppm.

Typeof

Food

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Indian Standards for plastics suitable for use in contact with food-stuffs, pharmaceuticals and drinking water are listed below:

IS No. Title

10171:1999 Guide on suitability of plastics for food packaging (second-revision).

9833:1981 List of pigments and colorants for use in plastics in contact withfoodstuffs, pharmaceuticals and drinking water.

9845:1998 Determination of overall migration of constituents of plasticsmaterials and articles intended to come in contact with food-stuffs � method of analysis (second-revision).

10141:1982 Positive list of constituents of polyethylene in contact withfoodstuffs, pharmaceuticals and drinking water (first-revision).

10142:1999 Polystyrene (crystal and high impact) for its safe use in contactwith foodstuffs, pharmaceuticals and drinking water (first-revision).

10146: 1982 Polyethylene for its safe use in contact with foodstuffs,pharmaceuticals and drinking water.

10148:1982 Positive list of constituents of polyvinyl chloride and itscopolymers for safe use in contact with foodstuffs,pharmaceuticals and drinking water.

10149:1982 Positive list of constituents of polystyrene (crystal and highimpact) in contact with foodstuffs, pharmaceuticals anddrinking water.

M Amount of extractive (Ex) = × 100 mg/dm2,

AM × 1000 mg/kg or mg/l and/or ppm V

where,

M = mass of residue in mg minus blank value

A = total surface area in cm2 exposed in each replicate, and

V = total volume in ml of simulant used in each replicate

(continued on next page)

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10151:1982 Polyvinyl Chloride (PVC) and its copolymers for their safe usein contact with foodstuffs, pharmaceuticals and drinking water.

10909:1984 Positive list of constituents of polypropylene and theircopolymers for their safe use in contact with foodstuffs,pharmaceuticals and drinking water (first-revision).

10910:1984 Polypropylene and its copolymers for their safe use in contactwith foodstuffs, pharmaceuticals and drinking water.

11434:1985 Ionomer resins for their safe use in contact with foodstuffs,pharmaceuticals and drinking water.

11435:1985 Positive list of constituents of ionomer resins for their safe usein contact with foodstuffs, pharmaceuticals and drinking water.

11704:1986 Ethylene/acrylic acid (EAA) copolymers for their safe use incontact with foodstuffs, pharmaceuticals and drinking water.

11705:1986 Positive list of constituents of Ethylene/acrylic acid (EAA)copolymers for their safe use in contact with foodstuffs,pharmaceuticals and drinking water.

12229:1987 Positive list of constituents of polyalkylene terephthalates (PET& PBT) for their safe use in contact with foodstuffs,pharmaceuticals and drinking water.

12247:1998 Nylon-6 polymer for its safe use in contact with foodstuffs,pharmaceuticals and drinking water.

12248:1998 Positive list of constituents of Nylon-6 polymer for their safe usein contact with foodstuffs, pharmaceuticals and drinking water.

12252:1987 Polyalkylene terephthalates (PET & PBT) for their safe use incontact with foodstuffs, pharmaceuticals and drinking water.

13449:1992 Positive list of constituents of ethylene vinyl acetate (EVA) fortheir safe use in contact with food stuffs, pharmaceuticals anddrinking water.

13576:1992 Ethylene methacrylic and (EMMA) copolymer and terepolymersfor their safe use in contact with foodstuffs, pharmaceuticalsand drinking water.

13557:1992 Positive list of constituents of ethylene methacrylic (EMMA)copolymer and terepolymers in contact with foodstuffs,pharmaceuticals and drinking water.

(continued from previous page)


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13601:1993 Ethylene vinyl acetate (EVA) copolymers for their safe use incontact with foodstuffs, pharmaceuticals and drinking water.

Doc: PCD 12(1328) Positive list of constituents of polycarbonate resins in contactwith foodstuffs, pharmaceuticals and drinking water.

Doc: PCD12 (1329) Polycarbonate resins for their safe use in contact with foodstuffs,pharmaceuticals and drinking water.

Doc: PCD 12(1331) Positive list of constituents of Melamine-Formaldehyde resinsin moulded articles in contact with food stuffs, pharmaceuticalsand drinking water.

Doc: PCD 12(1332) Melamine-Formaldehyde resins in moulded articles in contactwith foodstuffs, pharmaceuticals and drinking water.

Doc: PCD 12(1375) Positive list of constituents of Modified Poly (Phenylene Oxide)(PPO) in contact with food stuffs, pharmaceuticals and drinkingwater.

Doc: PCD 12(1375) Modified Poly (Phenylene Oxide) (PPO) resins in contact withfoodstuffs, pharmaceuticals and drinking water.

Doc: PCD 12(1516) Positive list of constituents of unsaturated polyester resins incontact with foodstuffs, pharmaceuticals and drinking water.


FOOD AND DRUGSADMINISTRATION, UNITEDSTATES

In the United States of America all thepackaging materials are evaluated for foodcontact application as per the Code of FederalRegulations 21, Parts 170 to 199, Revisedas of April1, 2001 Food and Drugs. (Table3.3 and 3.4).

Indirect Food Additives: General

Regulations prescribe that food additivesubstances may be safely used underconditions of good manufacturing practice.The quantity of any food additive substancethat may be added to food as a result of usein articles that contact food shall not exceed,where no limits are specified, that which

results from use of the substance in anamount not more than reasonably requiredto accomplish the intended physical ortechnical effect in the food-contact article;shall not exceed any prescribed limitations;and shall not be intended to accomplish anyphysical or technical effect in the food itself,except as such may be permitted by theregulations.

Any substance used as a component ofarticles that contact food shall be of puritysuitable for its intended use.

The existence of a regulation prescribingsafe conditions for the use of substance as anarticle or component of articles that contactfood shall not be construed as implying thatsuch substance as an article or componentor articles that contact food shall not be

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Table 3.3. Types of raw and processed foods (US FDA)

I. Nonacid (pH above 5.0), aqueous products; may contain salt or sugar or both.

II. Acid (pH 5.0 or below), aqueous products; may contain salt or sugar or both,and including oil-in-water emulsions of low- or high-fat content.

III. Aqueous, acid or nonacid products containing free oil or fat; may contain saltand including water-in-oil emulsions of low- or high-fat content.

IV. Dairy Products and modifications A. Water-in-oil emulsions, high - or low -fat B. Oil-in-water emulsions, high - or low -fat.

V. Low-moisture fats and oil.

VI. Beverages: A. Containing up to 8% alcohol. B. Non alcoholic C. Containingmore than 8% alcohol.

VII. Bakery products other than those included under types 8th or 9th of this table.

a) Moist bakery products with surface containing free fat or oil.

b) Moist bakery products with surface containing no free fat or oil.

VIII. Dry solids with the surface containing no free fat or oil (no end-test required).

IX. Dry solids with the surface containing free fat or oil.

construed as implying that such substancemay be safely used as a direct additive infood. Substances that under conditions ofgood manufacturing practice may be safelyused as components of articles that contactfood include the following subjects to anyprescribed limitations:

v Substances generally recognized as safein or on food

v Substances generally recognized as safefor their intended use in food packaging

v Substances used in accordance with aprior sanction or approval

Threshold of the Regulationfor Substances Used inFood-contact Articles

Substances used in food-contact articles

(e.g., food-packaging or food-processingequipment) that migrate, or that may beexpected to migrate, into food at negligiblelevels may be reviewed under the regulation.The Food and Drug Administration willexempt substances whose uses it determinesmeet the criteria.

Migration Limits

In the finished form in which it is tocontact food, when extracted with the solventor solvents characterizing the type of food,and under conditions of time and tempe-rature characterizing the conditions or itsintended use as determined from Tables 3.3and 3.4, the extractives shall not exceed 0.5milligram per square inch of food-contactsurface nor exceed 50 parts per million of thewater capacity of the container in general orotherwise limits specified for specific

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Table 3.4. Test procedures with time-temperature conditions fordetermining amount of extractives from the food contact surface or

uncoated or coated paper and paper-board, using solvents simulatingtypes of foods and beverages (USFDA)

Type Extractant

of

Food Water, n-Heptane, 8% 50%

time time alcohol, alcohol,

and and time & time &

temp. temp. temp. temp.

A High temperature I, IV B, VII B 250°F, - - -

heat sterilized III, IV-A, 2h 150°F, 2h - -

(eg., over 212°F) VII A -do-

B Boiling water I, VII B 212°F, - - -

sterilized 30 min

III, VII A -do- 120°F, 30 min - -

C Hot filled or II, IV B, Fill - - -

pasteurized VII B boiling

above 150°F Cool to

100°F

III, IV A - 120°F, 15 - -

VII A

V, IX - -do- - -

D Hot filled or II, IV B, VI B - - - -

pasteurized VII B 150°F, 2h - - -

below 150°F III, IV A, - 100°F, 30 min - -

VII A

V, IX - -do- 150°F, 2h -

VI A - - - -

VI C - - - 150°F, 2h

E Room temperature I, II, IV B, 120°F, - - -

filled & stored (no VI B, VII B 24hr

thermal rated & III, IV A, -do- 70°F, 30 min - -

frozen treatment VII A

in container) & V, IX - - 120°F, 24 h -

also in refrige- VI A - - - 120°F,

rated & frozen VI C 24hr

condition(continued on next page)

Co

de

Conditions

of use

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material when tested as per the prescribedmethod.

Further, most of the indirect food addi-tives used as adjuvant, production aidsand sanitizers for the manufacture ofpolymers coming in contact with foodstuffs are covered under part 178 of Codeof Federal Regulations 21 (Food andDrugs). Similarly, irradiation in theproduction, processing and handling offood and packaging materials for irradiatedfoods have been covered under part 179 ofthe US-FDA regulation.

EEC DIRECTIVES ON PLASTICCONTAINERS FOR FOODS

At the European level, FrameworkDirective 89/109/ECC defines comparablegeneral requirement for Plastic Container. Inthe early 1980�s, corresponding separatedirectives in the field of plastic utensils wereadopted at the European level, which alsoincluded procedures for carrying out suchmigration tests. European regulations havebeen harmonized to a large extent at leastwith regard to admissible monomers andstarting substances (positive lists) as well as

F Refrigerated III, IV A, 70°F, 70°F, - -

storage VII A 48 hr 30 min

(no thermal I, II, IV B, -do- - - -

treatment in the VII B

container) VI A - - 70°F, 48 h -

VI C - - - 70°F, 48 h

G Frozen storage I, II, IV B 70°F, - - -

(no thermal VII B 24 hr

treatment in the III, VII B -do- 70°F, - -

container) 30 min


The various specifications of US-FDA for plastic polymers coming incontact with foodstuffs are listed below (Indirect food additives):

Substances for Use Only as Components of Adhesives:

175.105 Adhesives.

175.125 Pressure-sensitive adhesives.

Substances for Use as Components of Coatings:

175.210 Acrylate ester copolymer coating.

175.230 Hot-melt strippable food coatings.

175.250 Paraffin (synthetic).

175.260 Partial phosphoric acid esters of polyester resins.

175.270 Poly (vinyl fluoride) resins.

175.300 Resinous and polymeric coatings. (continued on next page)

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175.320 Resinous and polymeric coatings for polyolefin films.

175.350 Vinyl acetate/crotonic acid copolymer.

175.360 Vinylidene chloride copolymer coatings for nylon film.

175.365 Vinylidene chloride copolymer coatings for polycarbonate film.

175.380 Xylene-formaldehyde resins condensed with 4,4�-isopropylidene-diphenol - epichlorohydrin epoxy resins.

175.390 Zinc-silicon dioxide matrix coatings.

Substances for Use Only as Components of Paper and Paperboard:

176.170 Components of paper and paperboard in contact with aqueous and fattyfoods.

176.180 Components of paper and paperboard in contact with dry food.

Polymers : Substance for use as basic components of single andrepeated use food contact surfaces:

177.1010 Acrylic and modified acrylic plastics, semirigid and rigid.

177.1020 Acrylonitrile/butadiene/styrene copolymer.

177.1030 Acrylonitrile/ butadiene/styrene methyl methacrylate copolymer.

177.1040 Acrylonitrile/ styrene copolymer.

177.1050 Acrylonitrile/ styrene copolymer modified with butadiene/styrene elas-tomer.

177.1060 n-Alkylglutarimide/acrylic copolymer.

177.1200 Cellophane.

177.1210 Closures with sealing gaskets for food containers.

177.1211 Cross-linked polyacrylate copolymers.

177.1240 1,4-Cyclohexylene dimethylene terephthalate and 1,4-cyclohexylenedimethylene isopthalate copolymer.

177.1310 Ethylene-acrylic acid copolymers.

177.1312 Ethylene-carbon monoxide copolymers.

177.1315 Ethylene-1, 4-cyclohexylene dimethylene terephthalate copolymers.

177.1320 Ethylene-ethyl acrylate copolymers.

177.1330 Ionomeric resins.

177.1340 Ethylene-methyl acrylate copolymers resins.

177.1345 Ethylene/1, 3-phenyle oxygenthelene isophthalate/terephthalate co-polymer.


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177.1350 Ethylene-vinly acetate copolymers.

177.1360 Ethylene-vinly acetate-vinly alcohol copolymers.

177.1380 Fluorocarbon resins.

177.1390 Laminate structures for use at temperatures of 250°F and above.

177.1400 Hydroxyethyl cellulose film, water insoluble.

177.1420 Isobutylene polymers.

177.1430 Isobutylene-butene polymers.

177.1440 4, 4-isopropylidene diphenol-epichlorohydrin resins, minimum mole-cular weight 10,000.

177.1460 Melamine-formaldehyde resins in molded articles.

177.1480 Nitrile rubber modified acrylonitrile-methyl acrylate copolymer.

177.1500 Nylon resins.

177.1520 Olefin polymers.

177.1550 Perfluorocarbon resins.

177.1555 Polyarylate resins.

177.1556 Polyaryletherketone resins.

177.1560 Polyarylsulfone resins.

177.1570 Poly 1-butene resins and butene/ethylene copolymers.

177.1580 Polycarbonate resins.

177.1585 Polyester carbonate resins.

177.1590 Polyester elastomers.

177.1595 Polyetherimide resin.

177.1600 Polyethylene resins, carboxyl modified.

177.1610 Polyethylene, chlorinated.

177.1615 Polyethylene, fluorinated.

177.1650 Polyethylene, oxidized.

177.1630 Polyethylene phthalate polymers.

177.1632 Poly (phenylene terephthalamide) resins.

177.1635 Poly (p-methylstyrene) and rubber modified poly (p-methylstyrene).

177.1637 Poly (oxy-1, 2 ethanediyloxycarbonyl-2, 6-naphthalenediyl) resins.

177.1640 Polystyrene and rubber-modified polystyrene.



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177.1650 Polysulfide polymer-polyepoxy resins.

177.1655 Polysulfone resins.

17731670 Poly (teramethylene terphthalate).

177.1670 Polyvinly alcohol film.

177.1680 Polyurethane resins.

177.1810 Styrene block polymers.

177.1820 Styrene-maleic anhydride copolymers.

177.1830 Styrene-methyl methacrylate copolymers.

177.1850 Textryls.

177.1900 Urea formaldehyde resins in molded articles.

177.1950 Vinyl chloride-ethylene copolymers.

177.1960 Vinyl cloride-hexane-1 copolymers.

177.1970 Vinyl chloride-lauryl vinyl ether copolymers.

177.1980 Vinyl chloride-propylene copolymers.

177.1990 Vinylidene chloride-methyl acrylate copolymer.

177.2000 Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

Substance for use only as components of articles intended for repeated use:

177.2210 Ethylene polymer, chlorosulfonated.

177.2250 Filters, microprous polymeric.

177.2260 Filters, resin-bonded.

177.2280 4, 4� - Isopropylidenediphenol epichlorohydrin thermosetting epoxyresins.

177.2355 Mineral reinforced nylon resins.

177.2400 Perflurocarbon cured elastomers.

177.2410 Phenolic resins in molded articles.

177.2415 Poly (aryletherketone) resins.

177.2420 Polyesterylate/poly (trimethoxysilylpropy) methacrlate co-polymers.

177.2430 Polyester resins, chlorinated.

177.2440 Polyestersulfone resins.

177.2450 Polyamide-imide resins.



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177.2460 Poly (2, 6-dimethyl-1, 4-phenylene) oxide resins.

177.2466 Polyoxymethacrylate/poly (trimethoxysilylpropy) methacrlateco-polymers.

177.2470 Polyoxymethylene copolymer.

177.2480 Polyoxymethylene homopolymer.

177.2490 Polyphenylene sulfide resins.

177.2500 Polyphenylene sulfone resins.

177.2510 Polyvinylidene fluoride resins.

177.2550 Reverse osmosis membranes.

177.2600 Rubber articles intended for repeated use.

177.2710 Styrene-divinyl benzene resins, cross-linked.

177.2880 Textiles and textile fibers.

177.2910 Ultra-filtration membranes.


maximum admissible migration of ingre-dients of plastics utensils. This also appliesto overall migration limitations, maximumadmissible residual content of certainmonomers and starting substances in plasticcontainer [so-called QM(A) limits], maxi-mum admissible migration limits of definedspecific substances [so-called SML(T)]. ECDirectives have laid down procedures forselecting food simulants and also require-ments for testing migration based on actualconditions of use (time/temperature combi-nations). On the other hand, the existingEuropean Directives mentioned above onlypartly cover the use of plastic additives and,at present, provide no regulations at allwith regard to aids to polymerisation andcolouring materials in plastics. In practice,the evaluation of plastic container (inparticular packages) with regard tocompliance with food regulation is a two-step procedure in most cases: at first, theingredients of the recipe are examined so asto ensure that the materials used are

admissible in principle. This examination isbased on existing European Directive. If, inthis first step, all components of the recipeturn out to be admissible in principle,migration tests are carried out in the nextstep in order to ensure that individualcomponents of the plastic container inquestion (e. g., additives, colouring materials,monomers, etc) are not transmitted to thefilling material (food stuff) to an inadmissiblygreat extent. The corresponding tests arepreferably carried out directly on therespective containers or on a test specimentaken from it, with specific attention paid tothe requirement that the overall migrationlimit and any specific migration limits bemet.

Migration Limits

In any such case, for substances exemptfrom specific migration limits or otherrestrictions in the list provided in Annex II,a generic specific migration limit of 60 mg/kg or 10 mg/dm2, according to the case, is

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applied. However, the sum of all specificmigrations determined shall not exceed theoverall migration limit, when tested as perTables 3.5 and 3.6.

SPECIFIC MIGRATION OFTOXIC ADDITIVES

In addition to creating safety and healthproblems during production, many chemicaladditives that give plastic products desirablepackaging qualities also have negative

environmental and human effects. Theseeffects include direct toxicity as in the case oflead, cadmium and mercury. Most of thecolourful pots or kudams, which are locallymanufactured by recycling, would havethese toxic additives. Plastic containers cancontaminate food because some chemicalsdiffuse from the packaging polymer of whichthey are made to the foods they contain.Migration potential exists for traces ofmonomers, oligomers, additives, stabilizers,

Table 3.5. Simulants according to EU Directive 97/48/EC

Simulant A:

Distilled water for aqueous foods having a pH of 4.5 or more

Simulant B:

3% acetic acid (w/v) for aqueous foods and acidic foods having a pH < 4.5

Simulant C:

10% ethanol (v/v) for alcoholic foods

Simulant D:

Rectified olive oil for edible oils and fats as well as fatty foods in which fat(is contained in a way that it) comes into direct contactwith the utensil in question.

Table 3.6. Migration tests of plastic materials and articles for certaintypes of foods according to EU Directive 97/48/EC

Food type Simulant

Only aqueous foods A

Only acidic foods B

Only alcoholic foods C

Only fatty foods D

All aqueous and acidic foods B

All alcoholic and aqueous foods C

All alcoholic and acidic foods C and D

All fatty and aqueous foods D and A

All fatty and acidic foods D and B

All fatty, alcoholic and aqueous foods D and C

All fatty, alcoholic and acidic foods D, C and B

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plasticizers and lubricants. Such substancesmay be toxic. A report of the Berkeley (U.S.)Plastics Task Force published in 1996 foundthat styrene from polystyrene, plasticizersfrom PVC, antioxidants from polyethyleneand acetaldehyde from PET have thepotential to contaminate food.

Vinyl Chloride

As per mutagenicity and metabolism ofVCM, a range of toxic effects has been reportedin human case studies. The principal effectsobserved include lesions of the bones in theterminal joints of the fingers and toes (acro-osteolysis) as well as changes in the liver andspleen. Long-term exposure gives rise to arare form of liver cancer (angiosarcoma) andthe association with exposure to VCM hasbeen reported amongst plant operatives in

several countries. In recent years, however,exposure to VCM at production andpolymerization plants has been markedlyreduced. It is well known that vinyl chloridecauses angiosarcomas of the liver as well astumours of the brain, lung and haemato-lymphopoietic systems in humans.

VCM limits : As per EEC directive, thelevel of vinyl chloride in materials andarticles and the level of vinyl chloridereleased by materials and articles tofoodstuffs shall be 1 mg/kg of PVC materialand 0.01 mg/kg of food.

As per Indian standard, the vinyl chloridemonomer content of PVC suspension resinused for the manufacture shall not exceed 5ppm, and in the PVC containers/film usedfor packaging shall not exceed 1 ppm. The

Table 3.7. European framework directives on separate materialsin contact with food are as follows:

Council Directive 89/109/ECC of 21 December 1988 (OJ L 040, 11/02/1989)

Directive 2002/72/ECC Plastic materials and articles.

Directive 90/128/ECC Plastic monomers.

Directive 82/711/ECC Basic rules for migration tests.

Directive 85/572/ECC List of simulants/foodstuffs.

Directive 80/766/ECC VC in PVC.

Directive 81/432/ECC Method of analysis for vinyl chloride released intofoodstuffs.

Directive 78/142/ECC Limits of vinyl chloride monomer.

Directive 80/590/ECC Determining symbols.

Directive 83/329/ECC Regenerated cellulose film (RCF).

Directive 84/500/ECC Ceramic articles.

Directive 86/388/ECC 1st amendment to 83/229/ECC.

Directive 92/15/ECC Amendment to 83/229/ECC.

Directive 93/8/ECC 1st amendment to 82/711/ECC.

Directive 93/11/ECC Nitrosamines in elastomers and rubber.

Directive 97/48/ECC 2nd amendment to 82/711/ECC.

Directive 2001/61/ECC Epoxy derivatives.

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residual migration of VCM into foodstuffsbeing packed shall not exceed 10 ppb. Themethod developed at CFTRI, Mysore, issuitable for estimation of RVCM content inPVC material and foods packed in themupto 0.01 ppm levels.

Vinylidene Chloride

Less is known of toxicology of VDC, bothin animals and in humans. The LD value forrats is around 1,500 mg/kg body weight,while in mice the value is 200 mg/kg bodyweight. VDC affects the activity of several ratliver enzymes and decreases the store ofglutathione. Some tumours have beenobserved after prolonged exposure but noteratogenic effects were seen in rats or rabbits.The main pathway of excretion is via thelungs, with other metabolites beingdischarged by the kidneys.

Acrylonitrile

AN is considerably more toxic than thechlorinated monomers and has LD value of80-90 mg/kg body weight in rats and 27mg/kg body weight in mice. It has also beenshown to be mutagenic after metabolicactivation with liver enzymes. In animals,AN is metabolized to cyanide, which isconverted to thiocyanate and excreted in theurine. There is also some evidence ofcarcinogenicity in animals and possiblyhumans too.

As per US-FDA, styrene-maleicanhydride copolymers shall not containresidual styrene monomer more than 0.1weight percent. In nitrile rubber modifiedacrylonitrile-methyl acrylate copolymers,the residual acrylonitrile monomer contentis not more than 11 parts per million.

Styrene

The LD value of styrene for rats is 5 g/kgbody weight. It is metabolized to styreneand its oxide, which is a potent mutagen ina number of test systems. Both styrene andits oxide have been prone to produce chro-mosomal aberrations under certain condi-tions. Toxic effects of styrene in humanshave been reviewed by IARC. The most fre-quently observed changes were of neuro-logical and psychological nature.

Limit : The total residual monomers, whenpresent, shall not exceed 0.2 percent by massof the polymer, as per Indian Standard. Asper US-FDA styrene-maleic anhydridecopolymers shall not contain residualstyrene monomer more than 0.3 weightpercent. Polystyrene basic polymers shallcontain not more than 1 weight percent oftotal residual styrene monomer.

Colourants in Plastics

Plastics are increasingly coloured toenhance the attractiveness of packaging, toprotect the contents from the adverse effectsof light or to differentiate between products.Depending on the type of packaging, thecontents and the storage conditions, it ispossible that components in the packaging,including colourants, could migrate to thefood. It must therefore be ensured that thepackaging components, including colou-rants, do not pose a health hazard to theconsumer. This is also the aim of the relevantdirectives, laws and regulations.

The colouration of plastics, which comeinto contact with food, is an importantapplication for the colourants industry. Thefollowing basic criteria are decisive for thesafe use of colourants for the colouration offood contact articles and packaging:

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1. Purity criteria of the colourants,

2. Its fastness to migration,

3. The tested toxicological properties.

The colourant manufacturers guaranteethat the colourants have been toxicologicallytested and that the purity criteria are met.The manufacturers of the food contact articleor packaging material are responsible for themigration testing.

Consumer safety is a joint responsibilityof manufacturers, processors and authorities.For the consumer, the safe use of colouredplastic food contact articles is alreadyprovided for by the current regulations incombination with a responsible approachby the pigment manufacturers andprocessors. Nevertheless, new knowledgemust always be taken into account.

Basically, the problem of colour migrationis found in vegetable oils, when they arepacked into coloured polythene containers.CFTRI has developed simple methods todetect the colour migration qualitatively fromplastics, within few hours, using decolouri-sed coconut oil. However, the quantitativeestimation can also be done using spectro-scopic analysis.

As per US-FDA 178.3297 Colourants andPolymers, the substances may be safely usedas colourants in the manufacture of articlesor components of articles intended for use inproducing, manufacturing, processing,preparing, treating, packaging, transportingor holding food. The term colourant means adye pigment, or other substance that is usedto impart colour to or to alter the colour of afood-contact material, but that does notmigrate to food in amounts that willcontribute to that food any colour apparentto the naked eye.

As per Indian standards, colour migratedto simulant or decolourised coconut oil orfood packed shall not be apparent to nakedeye. If the colour migrated is clearly visible,such materials are not suitable for foodcontact applications, even though theextractive value is within the limit as in IS:9833-1981.

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