J. Pack. Sci. Technol. Vol.5 No.4 (1996)

日本包装学会国際包装セミナー（IPS‘９６）要旨
The Environmental Debate : Recurring Themes andEmerging Trends-An International Perspective
Dr. Gordon L. Robertson
Vice President Environment & Communications
Tetra Pak Asia/Pacific Regional Headquarters
Tokyo, JAPANThe modern Green movement arose out of the nature and conservation societies of the late 19thand early 20th centuries. With the rapid industrialization of Europe in thel950s, local residents
became concerned about the construction of, for example, nuclear power plants. Protests
continued during the 1950s on a project-by-project basis, becoming increasingly critical of the"system" which was perceived as industry destroying the environment with no objection (and
often subsidies) from government.
Out of this background the Green Party was formed, achieving considerable electoral success inthel980s. Their declining support inl990 just 3.9% (attributed in part to the fact that themainstream parties had included environmental policies in their manifestos) was followed bytheir best ever performance in local elections in 1995 of 10%.
The German Green Party today is the strongest it has ever been. Now less ideological and nolonger a fringe party, it could assume a role as the kingmaker in c coalition governments. But to
get their support, governments will have to promise to undertake a restructuring of industry/society to make it more ecologically sensitive.
The Greens want society to make visible sacrifices for the sake of the environment. The big
question is: will packaging be a focal point of their activities, or (given that the DSD is now
running successfully ) will they address the really significant environmental issues in Germansociety, such as the use of the private motor car. They will likely push for a tax on CO2 and on
virgin raw materials.
Fashions change fast in greenery. Yesterday, the vogue was to proclaim imminentenvironmental catastrophe. Today it is to dismiss such talk as rubbish. 1995 saw a spate of"green bashing" with the publication of five books critical of environmentalists.
・ Life on a Modern Planet by Richard North・ Down to Earth by Matt Ridley
・ Small is Stupid: Blowing the Whistle on the Greens by Wilfred Beckerman
・ A Moment on the Earth by Greg Easterbrook- 243 -

The Environmental Debate: Recurring Themes and Emerging Trends

・

But is it true? A Citizen's Guide to Environmental Health and Safety Issues by Aaron
Wildavsky

Worthy of note is the fact that all five authors claim to be environmentalists. They are not reallyanti-Green but post-Green. They are against complacency and over-confidence and are rightly
sceptical of dogma. Their message is simple: green campaigners have distorted the truth, toldlies and made extreme statements to frighten the public. Greens respond that hyperbole isneeded in a market competition for funds.
However, the worthiness of a cause does not justify lying. If the evidence conflicts with thetheory, it is the theory which must yield, not the evidence. Closing our eyes to what is there
does not make it go away. What environmentalism needs most urgently is more evidence andmore research. We need to know what truth there is, if any, in some of the claims being made.
The authors sho w h ow the excited p redictions o f th e early 1970 s about wo rld famine andexhausted oil reserves were nonsense (proven reserves of oil are now larger than ever before
and fleet s of alte rnati ve fuel s are queuing up to take its place).
Ever since Rachel Carson, in her 1962 book The Silent Spring, predicted its imminent
extinction, the robin has been America's commonest bird.
In 1983, virtually everybody agreed that one-third of the trees in German forests were dying
from acid rain. Not only did far fewer die, but a 10 year, $500 mil. US study concluded thatacid rain was not even at the top of the list of problems facing forests, and the alarm spread
about acid rain was excessive. Current research suggests that leaf loss in European forests may
be due to the increasing density of tress within forests.
Th e seals o f the North Sea were suppo sed to be d ying fro m pollu tion in 1989; th ey wereactually suffering from a viral epidemic aided by high population density.
The Braer oil spill in 1994 was supposed to do irreparable damage to the wildlife of Shetland.
In fact the effect has been minimal.
The books argue that exaggeration, nationalization and central planning are the enemies of theenvironment, not the allies. Growth and technology are often the solution to a better
environment, not the problem they are frequently portrayed as.
Many of the present problems have arisen because Governments have subsidized industry andfailed to make the m "internalize the externalities", i.e. Pay for the use they make of theenvironment to absorb their waste products.
F e w l o c a l g o v e r n me n t s c h a n g e ci t iz e n s th e t r u e co s t s f o r w a st e c o l le c ti o n , r e c y cl i n g a n ddisposal, thus providing no incentive for waste minimization and relying on industry funding to
subsidize these activities.
Despite the fact that most dire predictions of environmentalists have not come true, Green- 2 4 4 -

J . Pa c k . S c i . T e c hn ol . Vo l . 5 N o. 4 ( 19 9 6 )groups remain extremely powerful as evidenced by the backdown by Shell in September lastyear over the dumping of the Brent Spar platform in the North Sea. One of the many lessons of
the Brent Spar affair - in which Greenpeace forced Shell to abandon its plans to dump theredundant oil platform in the deep Atlantic - is to underline the vulnerability of international
companies to environmental campaigns. It also demonstrates that technical arguments are nomatch for public gut feelings and sends a confusing message to companies who want to do the"right thing". What do people means by the "right thing" anyway? That which science dictates?
What regulators want? What environmentalists value? What the public desire? What consumers
would like? Unfortunately, much of the regulation which impacts on the packaging industry isbased on false perceptions and myths held by the public and politicians.
It makes no sense to recover materials from the waste stream at any cost, simply because they
are physically recoverable or merely to reach targets. It makes no sense to subsidies inefficient
markets since to do so prevents sustainable, long-term, competitive markets from emerging.
Reaching the recycling targets will not solve any environmental problems. What is required is abetter system, not bigger targets.
One of the most encouraging trends over recent years has been the increasing availability of
information on packaging, solid waste and the environment. Such information is sorely needed
to replace the black hole of ignorance on which most packaging legislation has been based.
One popular myth or recurring theme around the world is that the quantity of packaging isincreasing much faster than population and we will soon be buried under a mountain of used
packaging. Data to rebut this myth is generally unavailable; the US EPA study is an. exception.
Growth of population from 1970 to 1988
compared to the increase in MSW discards
Population
MSW Discards
Selected Components of Discards:
Food, yard and miscellaneous inorganic waste
Reading materials
Durable good
Office and other paper
Clothing and footwear
Miscellaneous non-durable goods
Containers and packaging

21%
38%
24%
44%
63%
87%
60%
47.5%
9%

Source: US EPA Characterization of MSW in the United States: 1990 Update 38:46
This data clearly demonstrates that while MSW has increased almost twice as much as
population, containers and packaging have actually decreased. The biggest increase has been in
non-durable goods such as disposable diapers.

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T he En vi r o nme n ta l D e bate : R ec ur r in g T he me s a n d E me rg in g Tr e nd s

Facts such as these need to be communicated to politicians, policy-makers and the public. It isimperative that legislators and policy-makers have the flexibility to modify their laws and viewsin the light of facts which were previously unavailable.
Former EPA official Dr. Winston Porter (now a private consultant to industry and government)
in a recent report entitled Recycling at the Cross-Roads states that "a practical upper limit
for a national recycling rate is 33%. A good target for most locations is 20 - 30%". He doubtsthat the effort to greatly expand curbside programs would be worth the money: "For the people
who have a desperate need to feel good, you can always have a drop-off bin".
His study shows that the USA is on a much faster and more efficient track than the Europeans,
and is already recycling at a rate which Europe hopes to reach in about five years. Based on his
study of German, French, British and European Union recycling approaches, he complied a setof principles.
Firstly, deal with all the trash in MSW, not just the one-third which is packaging. Many nonp a c k a g i n g i t e ms a r e r e c y c l e d i n t h e U S , i n c l u d i n g n e w s p a p e r s , o f f i c e p a p e r , t e l e p h o n edirectories and yard wastes.
Secondly, set overall recycling goals, not material-specific mandates. Recycling applies very
differently to various materials and products. While it makes sense to recycle aluminium cansbecause of the large amounts of energy required to produce them, plastic wastes arelightweight, thus making collection and sorting expensive. Since plastic packaging requiresvery little energy and raw material to produce, it has less value for recycling.
Thirdly, don't set unreasonable recycling rates and d ates. The Ger man s have sh o wn how
expensive it is to set high rates (70%) to be reached in short time frames (about 3-4 years).
Their overall recycling costs are about US$500 per ton versus US$150-200 in the US.
Fourthly, leave the basic MSW collection and sorting operations with municipalities. As theGermans have illustrated, it is extremely expensive to operate public and private collection
systems side-by-side. Industry's role is primarily to recycle collected materials, and billions
have been spent in doing so in the US.
One important emerging trend is the increasing data on the actual costs involves in diverting
household waste from landfill. Many local governments have introduced curbside collection
and other diversion schemes without any idea of the likely costs. When they find out just how
expensive such schemes are, they then turn to industry for funding. Having good data on actual
costs might dissuade municipalities from introducing such schemes, or at least bring somerealism to their discussions.
An emerging trend is the scientific studies by universities and research institutes into theenvironmental and economic limits to recycling. For example, listed below are the titles ofseven papers presented at the international recycling congress R'95 held in Geneva last year.

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J. Pack. Sci. Technol. Vol.5 No.4 (1996)

・
・
・
・
・
・
・

Ecological limits of recycling - Germany
Environmental impacts by disposal processes - Denmark
Environmental assessments of products and recycling of packaging - Switzerland
Ecological and economic limits on recycling - Switzerland
Ecological, economic and technical limits to recycling of packaging material - Switzerland
Costs and benefits of recycling - UK
Is separation of waste always justified? - Switzerland

While most of the studies arc at a preliminary stage, they suggest that recycling is not always
the most sensible valorization technique for packaging material, and that the environmental
impacts of recycling are often as great (or sometimes greater) than virgin material production.
As an industry, we should be encouraging similar studies in our own countries.
In discussions about recycling, much is said about "closing the loop", i.e. recycling the used
p ac k ag e b ac k in t o a n o th e r si mi l a r p ac kag e. Gl a s s an d me t a l p ac k a g e ma n u f ac tu r e r s a r eparticular exponents of closed loop recycling because it is technologically simple for them todo, and in the case of glass, it is really their only option.
However, it is important to realise that the physical environment (i.e. what we are all working
to preserv e) is un concerned with whether the recycling is closed or open loop. What is
important are the overall environmental impacts of the recycling processes. If open loop impacts
are lower than closed loop, then open loop recycling should be promoted.
Moves by governments and some sectors of the packaging industry to set mandatory recycledcontent in packaging is nothing more than an interventionist, "command-and-control" attempt todevelop markets for recycled materials in the hope of making curbside recycling financially
viable. While the glass, metal and PET packaging manufacturers can achieve high recycledcontent, there are technological and safety reasons which preclude paper and other plastic
p a c k a g i n g i n d i r e c t c o n t a c t w i t h f o o d f r o m d o i n g t h e s a me .
Also, since the recycled content of a package cannot be measured for most packaging materials,
mandatory recycled content is unenforceable.
An emerging trend is the move towards green or environmental marketing. Marketing gurus areconvinced that this is a huge business opportunity as the following quote from Tom Peters (coauthor of In Search of Excellence) demonstrates:"The environment is the biggest business opportunity that confronts virtually any human being
in business. The greening of the market is a 'remarkable, perhaps once-in-a-century
opportunity 'for the corporation wise enough to seize it. "At Terra Pak we believe that it makes sense to try and obtain a competitive advantage from theenvironmental profile of our packaging systems.

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The Environmental Debate : Recurring Themes and Emerging Trends

Further support for green marketing is provided by Professor Philip Kotler whose classic
textbook Marketing (now in its 6th edition) is still being used in universities over 35 years
since the first edition appeared.
Business have recently embraced 'customer-centered marketing' and ' environmental
marketing'. Consumers have been crying for a better environment and smart marketingcompanies have already been responding - and earning money in the process. "The message is clear: environmental advantages are competitive; the environment is a business
opportunity; environmental marketing is the way of the future. The only caution I would offer
is that environmental marketing claims be based on facts rather than fantasies dreamt up during
the excitement of a marketing strategy meeting.
Another emerging trend is the increasing demand by consumers for verification of the ecoperformance of a product or its packaging, life cycle analysis is one tool which has a role toplay here. However, trying to summarize LCA results into meaningful, balanced statements is
an incredible challenge for technical and marketing staff alike.
I believe increasing use will be made of environmental audits to quantify the emissions to air,water and land from specific manufacturing sites. These will then serve as benchmarks, andthrough continual improvement, the emissions will be reduced over time.
In addition, more and more companies are installing environmental management systems which
will be able to be certified against ISO 14001 when it is released later this year. It is important
for the packaging industry to enthusiastically embrace environmental audits and EMSs, not only
to show its commitment to reducing environmental impacts, but also to turn the spotlight awayf r o m p o s t -c o n su me r p a ck ag in g t o w a r d s a l i f e c y c l e v i e w .

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J.

Pack.

Sci.

Technol.

Vol.5

No.4

(1996)

日本包装学会国際包装セミナー（IPS‘９６）要旨
IBM Status of Environmental Issues in Packaging
Mr. Alvin R. Voss
Senior Engineer
IBM Corporation
Worldwide Distribution Engineering Services
Releigh, USA

MISPERCEPTIONS
Since packaging represents one-third of municipal solid waste it has gotten a lot of attention in
re-cent years as the environmental "bad" guy. The most adamant critics would like to eliminate
packaging altogether, while others push for recycling everything. A recent study by the United
Kingdom Center for Economic and Environmental Development came up with several
interesting conclusions related to packagin g an d it role in our everyday lives.
・

・

・
・

The public pays dispropo rtionate attention to packaging a s an envi ron mental i ssue .
"Casual and pejorative use of the term 'over- packaging' often stems from a lack ofunderstanding of the purpose of packaging and the processes involved in its
selection."
Consumers are unaware of the role played by packaging upstream, and their perceptions
can be misguided. But "they are unlikely to purchase a product if the packaging has
failed."With constant pressure to drive down production costs, "it would defy economic logic
for a co mpany to package a product purposely in excessive materials."
New laws should be based on fact, not supposition. "Much of the legislation reflects akneejerk response to a perceived environmental problem. Policy should be chosen for its
overall effectiveness and not just for its ability to address single, high profile concerns."

Packaging selection involves trade-offs between numerous environmental and marketing
criteria. For example, a product which is susceptible to theft or tampering may require security
measures be incorporated into the package design. If everyone agrees that preventing producttheft or tampering is a legitimate packaging function, then the additional resources to provide
this function are justified.
Market fo rces should encourage all participants in the supply chain to mi nimize p ro duction
costs, including the costs of packaging. If the market works effectively, only the necessary
packaging for a given product will be used.

REALITY
Studies have shown that in less developed countries packaging actually reduces solid waste and- 249 -

IBM Status of Environmental Issues in Packaging

improves the standard of living because it allows food and products to be shipped from farms
and factories to the consumer virtually free of damage or spoilage.
Eliminating packaging is not the answer. Neither is 100% recycling. Given today's
technologies, it is not practical to recycle all packaging materials due to contamination,
degradation of materials, small volumes and lack of commitment by the consumer in collection.
S o u r c e r e d u c t i o n i s a c o n t i n u i n g t r e n d i n p a c k a g i n g. L i g h t w e i g h t i n g i s g o o d f o r t h eenvironment and also makes good economic sense for industry. Less material usually means
lower costs. Many companies are implementing environmental packaging designs and saving
money at the same time.
Recycling is steadily expanding and brings in line the chain of independent activities necessary
for success. Tens of thousands of communities around the world have or are implementing
curbside collection programs or local drop-off centers. At the same time numerous companies
are finding that recycling packaging materials from their manufacturing processes also pays big
dividends and reduces costs.
Governments around the world are passing new non-uniform and often conflicting legislation.
M a n y c o u n t r i e s s u c h a s U . S ., G e r ma n y , t h e E E C , C a n a d a a n d J a p an , a r e a l l c r e a t i n glegislation which is seriously compounding the problems and exposures of international
companies. Outlined below are IBM's efforts to address these problems.

IBM 's ENVIRONMENTAL PACKAGING PROGRAM
SUMMARY:
Environmental issues have and will continue to influence the packaging materials and design
characteristics for IBM products, parts and supplies. In late 1990, IBM's Worldwide
Distribution Engineering Services department, (WDES) located in Research Triangle Park,
North Carolina was assigned the responsibility to implement a formal environmental packaging
program for the IBM Corporation. The first task was to develop a worldwide environmental
packaging strategy which would meet the general objectives of reduce, reuse and recycle. An
Environmental Design Guide was written to address these environmental packaging issues
being identified by local, state, federal and international governments. The Guide has been
distributed to all IBM worldwide packaging organizations to assist them in lessening the impactof IBM's packaging on the environment.
The environmental concerns addressed are:・・・

Process biproduct problems (e.g. CFCs, dioxins, heavy metals);
Methods for reducing the amount of packaging required;
Increasing reusability of packaging designs;- 2 5 0 -

J. Pack. Sci. Technol. Vol.5 No.4 (1996)

・・・

Refurbishing and reusing versus purchasing new (e.g. pallets);
Improving recycling through use of proper symbology identifications;Improving recycling by requiring more recycled content.

WDES has also developed a Corporate Bulletin and three engineering specifications as
additional tools to assist in the uniform implementation of IBM requirements:
・・・・

Environmental Packaging: Requirements for Products, Parts & Supplies;
Expanded Packaging Materials: Prohibited Blowing Agents (for CFCs);
Packaging Materials: Restricted Heavy Metals;
Recyclable Packaging Materials: Selection and Identification.

These specifications are identified on packaging engineering drawings for procuring packaging
materials and electronic parts from IBM suppliers.
WDES has also developed environmental packaging initiatives with planned complianceschedules worldwide to insure improvement activities are uniformly implemented. Listed below
are the initiatives that have been implemented thus for.
・
・
・
・
・
・
・
・
・
・

Eliminate " CFC" blowing agents from foam products
Control "heavy Metals" in packaging
Added recycle symbols to cartons
Added resin codes to plastics
Changed from white corrugate to kraft color
Eli minate "PBBs/PBBOs" in plastic packaging
Extend above requirements to parts suppliers
Minimum 50% recycled con tent in corrugate
Minimum 15% recycled resin in polyethylene foam
Minimum 25% recycled resin in polystyrene foam

To help encourage implementation of the above initiatives, an internal IBM competition wasstarted by asking our worldwide IBM packaging engineers to submit their environmental
projects, which conformed to the corporate strategies, to WDES for evaluation. Based on how
well the projects met the objectives of the guide and initiatives, a winner was selected from thesubmitting sites. The winning site is awarded a site plaque and each individual who participatedin the implementation of the environmental packaging projects is also given a plaque. Our
Rochester, Minnesota manufacturing site won the award in 1989 and 1990. They were cowinners in 1991 along with our Research Triangle Park, North Carolina manufacturing site. In
1992 our San Jose site won the award. In 1993, 94 and 95 our Greenock, Scotland site won
the award. This internal award has been the spring board for these sites to pursue additional
awards. In 1993, Rochester won the Minnesota Governors Award for Excellence in Pollution

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IBM Status of Environmental Issues in Packaging

Prevention and in that same year the San Jose packaging engineering department won IBM's
prestigious "Environmental Affaire Technical Excellence Award. " From 1990 to 1995 over
250 environmental packaging projects have saved IBM in excess of $90 million.
GOALS:IBM has three key goals for 1996 to reduce, reuse and recycle as much packaging
material as is economically and technically feasible. The goals are:・

Increase product and part ruggedness in order to reduce the need for excessive packaging
protection.
・ Continue to create tools and provide information which will assist IBM packaging
engineers in their continuing effort to reduce, reuse and recycle.
・ Update environmental packaging symbols to be consistent with new EU symbols.
ORGANIZATION :・

WDES, IBM's packaging engineering competence center, continues to set and drive
IBM's efforts to implement environmental packaging. Each year the group sponsors aninternal competition among all manufacturing sites to recognize environmental
contributions with a focus on source reduction.
・ Individual manufacturing sites have established working groups which meet periodicallyto identify, analyze and track environmental packaging improvements for suppliers andinterplant shipments.
・ WDES works closely with our Corporate Environmental Programs group to evaluate
strategies in the environmental area.
ACTIVITIES :
・
・

・

・

There were approximately 150 environmental packaging projects implemented since 1990
at IBM sites around the world. These projects covered reduction, reuse and recycling.
New products are being tested in our packaging labs to increase their ruggedness, thus
reducing the need for packaging. As ruggedness increases, shock absorbing foams arebeing replaced by corrugate and recycled paper pulp cushion designs.
Conservative measurements indicate that approximately one million cubic feet ofpackaging materials were diverted from landfills over the past few years. This figure does
not include manufacturing process related packaging material diverted from land fills.
These materials are collected, sorted and recycled at approximately a 70 percent level.
IBM has been part of several benchmarking studies which included comparisonof environmental packaging, and IBM was rated as one of the best.

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J. Pack. Sci. Technol. Vol.5 No.4 (1996)

BENEFITS :・・・・Over $90 minion saved fro m 1990 th rough 1995.
Better positioned to meet current and future regulations.
Increased employee awareness of the need to be involved in helping reduce solid waste.
Improved customer satisfaction by demonstrating our commitment to reducing
packaging's environmental impact.

PROBLEMS :・The hostile environment in which our products are shipped plays an enormous part indictating the amount of packaging protection required to get our products delivered defectfree.
・Conflicts in local, state, national and international regulations continue to cause major
p r o b l e ms a n d i n c r e a s e d ma n u f a c t u r i n g c o s t s .
・Packaging can not be continually source reduced without compromising safety andpackage integrity.
・Being competitive in the market place requires that environmental packaging projects becost justified or at least break-even.
・The transportation industry needs to become a partner in the effort to reduce packaging.
・Most consumers are not knowledgeable and/or motivated enough to recycle our type of
packaging.

FUTURE:・ C o n t in u e t o b e en v i r o n me n t a l l y p r o a c t i v e .
・Continue IBM initiatives to increase minimum recycled content in our packaging
materials.
・Provide IBM customers with packaging that is locally 100 percent recyclable.
・Complete the development of packaging material tracking and reporting program called
TRTRAK.
・Complete the integration of environmental packaging principles and goals into the productdevelopment and manufacturing processes worldwide.

CONCLUSION:
A free market relies on consumer choice, with nearly all forms of consumer demand being
regarded as legitimate. If laws are passed that circumvent this principal they are almost always
doomed to failure or expensive means are used to prop them up. One only needs to look atsome existing programs to see how expensive this kind of folly can be. Finding the best andleast expensive alternative requires government and industry working together.

- 2 5 3 -J.

Pack. Sci.

Technol.

Vol.5

No.4

(1996)

日本包装学会国際包装セミナー（IPS‘９６）要旨
Quality Protection of Food by Packaging
Prof. Ivan Varsanyi, Ph.D., D.Sc.
University of Horticulture and Food Industry,B u d a p e s t , H u n g a r y

One of the main purpose of packaging is to protect the quality and the quantity of packed
goods. In the case of foods it means that the well constructed package keeps the sensory andnutritive value of food from the procedure of packaging to consumption.
The quality changes of foods and the “quality” of packaging has a stochastic relationship, since
the quality changing of food depends on the chemical components, physical and biological stateof food items. Consequently the rate of deterioration determine the time of keeping quality
including the shelf-life of packed foods.
It is a well-known fact that the ,,quality" of the packages has a tight correlation with the barrier
properties of the packages and the packaging materials. The barrier properties of packages
depend on the forming and sealing technology and in the case of packaging materials it is thefunction of morphologic structure what is especially effective to the polymer base packaging
materials.
Our studies performed had two main lines: we analyzed the causes of food deterioration usingchemical, physico-chemical, physical and sensoric methods and we investigated the barrier
properties of packaging materials first of all on polymer base. For conclusion we searchedcorrelations between the rate of food deterioration and the protective effects of packages.

Quality changes of foodQuality changes of food usually have a negative character - apart from some exceptions as the,,ageing" of viticultural products or of cheeses - what results the deterioration of the food.
Obviously, changes deriving from the insufficient operation of technologies do not cover thephenomena.
Chemical origin of quality changing has direct and indirect effects. Direct effect is the oxydationof food components. The very significant changing is the rancidity of foods. We can also
realize the non-desirable enzyme activity what changes the food matrix and in that the level ofcomponent concentration. Indirect effect is for example the catalyses of heavy metal molecules
or light as energy source of quality chan ging reactions.
Physical origin of quality changing are mainly caused by the micro- and macro-climate
differences inside and outside of package. It means that the water content of food can bechanged according to the changing of relative humidity. It is a direct effect what also keep inhiding an indirect effect when the aroma components are evaporating with water vapour asaseotropic molecule mixture.

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Quality Protection of Food by Packaging

We have to mention the direct effect of temperature on food quality. The texture and theologicalbehaviour may change according to the fluctuation of temperature e.g. during storage,transportation and selling.
The strange material penetration is another important group of deteriorative physical changing.
The various auxiliaries of packaging material production including the solvents of printing are
the sources of strange materials. In extreme cases monomers and/or oligomers may also
penetrate into the packed food.
Microciological origin of quality changing is very frequent reason of food deterioration. The
quality changing is caused by the multiplication of microorganism in the food or by infection of
microbes and as a result of their activities carbohydrates, proteins and lipids may decompose infood. The insufficient water activity may increase the activity of microorganisms and theconsumption of food will be restricted. The aseptic technologies and the vacuum and inert gas
atmosphere packaging can also reduce or stop the microbial activities.

Quality protection by packaging
According to our observation it may be stated that the reactions effect on the quality at sametime or - in most cases - parallely in space and time and in addition they usually interact witheach other. The reactions of deterioration often take place with quality changes induced by the
propagation of food micro flora, too.
First of all for the improvement of quality protection by packaging the barrier properties of
packaging materials were studied. The consideration based on the following equation for thequantity determination of permeating gases and vapours when the temperature is constant.

( 1 )where Q = quantity of permeating materials, P = permeability constant, A = active surface, Ap= pressure difference of two sides of package, t = time of permeation (storage) time, 1 =thickness of packaging material.
In the above mentioned equation the permeability constant (P) is in ratio with the diffusion (D)and solubility (S) coefficients, with other words the quantity of material transmitting through amembrane or foil (of unit surface and thickness in a time unit at a given temperature andpressures differences) will be equal with the product of diffusion coefficient (on surface andtime unit) and the solubility coefficient (of the mass unit of material transmitting through a unit
volume of the membrane).
P=DS

(2)

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J. Pack. Sci. Technol. Vol.5 No.4 (1996)

Analysing the possibilities of food quality protection and the improvement of it by packaging it
may be stated that the interpretation of Equation 1 helps us in this matter. The key factor is thepermeability constant (P), because the storage time is usually given (shelf-life), the changing of
the active surface (A), and of the thickness of the packaging material ( 1 ) is very limited
regarding to the aspects of package design, furthermore the modified atmosphere can influence
the value of Δp, but it needs a special technique. The components of Equation 2 call ourattention to the importance of morphologic structure of packaging materials in the case ofpolymer foils and containers.

Effects of packaging material structure
Most of the solid polymers consist of ordered and disordered or with other words crystallic andamorphous parts. Accordingly, when polymer foils as packaging materials are examined, ther a t i o o f c rys t a l l ic a nd a mo r p h ou s p a r t s h a v e to b e c o n si d e r e d a s t h e b as i c st r u ct ur a lcharacteristic significantly influences the quality of the polymer. When the permeability is
tested, especially important is to consider the ratio of amorphous and crystallic parts because aclose correlation ex ists between the micro morphology of th e poly me rs and the barrier
behaviour.
Experiments prove that three groups of solid polymers show especially good correlation
between the crystallic (ordered part) content and the permeability: these are polyethylenes,
vinyl-polymers, or copolymers and fluorized hydrocarbons.
Experiments also proved the correlation between the crystallic content of polymers and thepermeation of gases or water vapour. The permeability of the polymer has a linear correlation
with the amorphous content as it is described by the following equations:P= D S a X a = P a X a

( 3 )

S

= S a X a

( 4 )

where
and
P a

=

D S a

( 5 )

where Xa shows the ratio of amorphous part in the polymer (index ,,a" marks the behaviour of
the amorphous part). It means that the value of permeability constant depends on the quantity of
the amorphous (or the crystallic part) and in many cases the specific volume gives a good
information on the crystallic content in the same polymer (e.g. polyethylenes).
The crystallic part of the plymer is practically not active for the permeation and there is no
direct effect to diffusion in the amorphous part, but the dispersion of crystallic agglomerates caneffect on the quantity of the permeated molecules. This means that the actual free path for the
diffusion of molecules is longer than it should be calculated from the thickness of themembrane. Thus, to the mutual effect of these factors the value of the diffusion coefficient (D).

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is smaller than it would be in case of the completely amorphous polymer (Da). It may bedescribed by the following equation:(6)

where τ is the factor of proportionality, it expresses the increased free path length of the
diffusing molecule which derives from the dispersion of the crystallic parts in the membrane,
too. Results also unambigously prove that the quantity of a given permeating gas has a linear
correlation with the ratio of ordered (crystallic) and/or disordered (amorphous) parts.
It may be stated from the above that the quantity of the permeating material may be wellestimated by calculation if the structure of the polymer and the permeating molecule(s) are
known. This means, that at a given packaging material, for example the change of the moisture
content in the packed food may be predicted if the storage conditions are known (temperature,humidity)

Effect of temperature
The quality changing of foods and the permeability of polymers depends on the temperatutre
since they change exponentially when it increases or decreases as it follows:

(7)

(8)

where Ea = activation energy of reaction, Ep = activation energy of permeability, R = universal
gas constant, T = temperature in K. For the Ea or Ep calculation it can be use a transformationt o l o g P a n d l / T .
It may be stated that the effect of temperature is important from the aspects of the fooddeterioration and of the permeability of packaging materials. Consequently the optimization oftemperature effect has a basic interest.

Conclusion
The quality protection plan of packed food needs information about the barrier properties of
packaging materials and containers, the expected keeping quality or shelf-life of food, and thestorage conditions as temperature, relative humidity and illumination. The rate of qualitychanging of packed food depends on the barrier properties of package and in addition there is a
proportional relation between the package form or container - it means the active surface size

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and the wall thickness -and the quality protection. It must be emphasize that the barrier
behaviour and the convertibility of the packaging material is determined by the microstructure.
The quantity of strange materials also influences the rate of food deterioration and/or thesensoric quality of food. The hygienic state of packed food and the storage conditions are
determinants. The quality of packaging can not compensate the effect of temperature on thefood deterioration. The behaviour of the critical properties of food also depends on thetemperature. Consequently the quality protection of food requires comprehensive investigations
and tests because the task is multidisciplinary.

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