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ASEPTIC PACKAGING SYSTEM

A

septic packaging can be defined as the filling of a commercially sterile product into a
sterile container under aseptic conditions and hermetically sealing the containers so that
reinfection is prevented
...

The term “aseptic” is derived from the Greek word “septicos” which means the absence of
putrefactive micro-organisms
...

Examples are milk and dairy
products,
puddings,
desserts, fruit and vegetable
juices, soups, sauces, and
products with particulates
...
Examples of this application include fermented dairy products like
yoghurt
...
In canning, the process begins with treating the food prior to filling
...
The package is cleaned, and the product is introduced into the package, usually hot
...
The package is
hermetically sealed and then subjected to heating
...
Packages containing low-acid
(above pH 4
...

Although conventional canning renders food products commercially sterile, the nutritional
contents and the organoleptic properties of the food generally suffer in the processing
...

Figure 1 is a simple illustration comparing the basic difference between conventional canning
and aseptic packaging processes for the production of shelf-stable food
products
...

Therefore, light weight materials consuming less space offering convenient features
309

Figure 1: Conventional Canning v/s Aseptic Packaging
Conventional Process Flow

Aseptic Process Flow

Package

Product

Package

Filling

HTST Processing

Sterilization

Sealing

Cooling

Product

Filling

Retort Processing
Sealing
Cooling

Storage/Distribution

Storage/Distribution

and with low cost such as paper and flexible and semi-rigid plastic materials can be
used gainfully
...


•

Extension of shelf-life of products at normal temperatures by packing them
aseptically
...


Aseptic Processing – Methodology
Aseptic processing comprises the following:
• Sterilisation of the products before filling
• Sterilisation of packaging materials or containers and closures before filling
• Sterilisation of aseptic installations before operation (UHT unit, lines for products, sterile
air and gases, filler and relevant machine zones)
310

•
•

Maintaining sterility in this total system during operation; sterilization of all media entering
the system, like air, gases, sterile water
Production of hermetic packages

Sterilization of Products
In aseptic processing, the design to achieve commercial stability is based on the well-founded
principles of thermal bacteriology and integrated effect of time/temperature treatment on
spores of micro-organisms
...
Heating and cooling should
be performed as rapidly as possible to achieve the best quality, depending upon the nature
of the product
...

Various heat transfer methods are used, but essentially the systems can be divided into direct
and indirect heat exchange methods
...

TABLE 1
Characteristics of the Heat Exchange Systems
Used for Aseptic Processing of Liquids
Equipment
Type

Product
Quality

Aroma Energy
Reten- Saving
tion

Steam
Injection/
Infusion

Excellent No

Poor

Plate Heat
Exchanger

Good

Excellent Low

Yes

Capital
Cost

Space

Pulp
Fouling
Capabi- Length
lity
of Run

High

Fair

FairGood

Turndown*

Excellent Fair

Excellent Limited Limited

Good

Tubular:
• Small Tubes Medium Yes
• Large Tubes Poor
Yes

Fair
Fair

Medium Good
Low
Fair

Good
Good

Limited
Good

Good
Good

Swept
Surface

Very
Poor

Very
High

FairGood

Good

Good

Good

Yes

High

(* Turndown is the capability of the system to process at different rates to accommodate different
number of fillers or different package sizes
...
Practical
considerations and regulatory requirements have limited the number of sterilants, which
are used for aseptic systems
...
Product supply lines and fillers are commonly sterilized by ‘moist’ heat in the
form of hot water or saturated steam under pressure
...
However, due to the relatively high
dry heat resistance of bacterial endospores, the time-temperature requirements for dry heat
sterilization are considerably higher than those for moist heat sterilization
...
Systems employing moist heat are frequently
sterilized at temperatures ranging from 121°C to 129°C, while 176°C to 232°C is used
for sterilization by dry heat
...


• Chemicals
Hydrogen peroxide is the overwhelming choice for use as a chemical sterilant
...

Hydrogen peroxide is not an efficient sporicide when used at room temperature
...
Therefore,
most aseptic packaging systems use hydrogen peroxide (at concentrations of 30 to 35%)
as a sterilant for packaging materials followed by hot air (60°C to 125°C) to dissipate
residual hydrogen peroxide
...
Due to the penetrating
powers of gamma-radiation, packages are treated in bulk at commercial irradiators
...
5 Megaradians (Mrad) is commonly used to decontaminate
containers for acid and acidified food
...
Doses required to sterilize
containers for use with low acid food are considerably higher than those required for
acid and acidified food
...
Ultraviolet (UV-C) light
has been used to decontaminate food contact surfaces
...
While equipment size, speed and costs have precluded use of
electron beam irradiators until now; it is only a matter of time before such a system is
developed
...
The tube provides the required residence time at the sterilisation temperature
...
Since there is some loss of
temperature as product passes through the holding tube, the product temperature must be
sufficiently high on entering, so that even with some temperature drop, it will still at least
be at the prescribed minimum temperature at the exit of the holding tube
...


•

A deaerator is used to remove air, as most products, which are aseptically processed, must
be deaerated prior to packaging
...
The
deaerator generally consists of a vessel in which the product is exposed to a vacuum on a
continuous flow
...
The
valve system that connects the surge tank between the end of the cooling section and the
packaging system, allows the processor to carry out the processing and packaging
functions more or less independently
...
The positive pressure must be monitored and controlled to protect the tank from
contamination
...
The integrity of the closure and seal is
therefore of paramount importance
...
To avoid recontamination, the production
units, which are tight are required
...

In the longitudnal system, a flat web of packaging material is used, supplied in reels
...
The strength of this longitudinal seam is determined partly by an “overlap
seal” and partly by a plastic longitudinal strip
...
Both these operations, the strip application and
the actual longitudinal sealing are done by using sterile, hot air and pressure (Figure 2)
...
By
constantly moving sealing and pressure jaws, pressure is applied from the outside of the
packaging material tube squeezing the product from the sealing area
...
The polyethylene layer is heated, melted and pressed
together between a pair of jaws
...

Maintenance and preventive maintenance is needed to ensure satisfactory seam quality as
well as to prevent damage of the packaging material in general, which may interfere with
the tightness of the container
...


Types of Aseptic Packs
Consumer Packages
A great variety of packages may be aseptically filled now as listed
...


•

Bags and Pouches: Pillow pouches are usually used for packaging of milk; three-sided
sealed pouch, however, is suitable also for aseptic packaging of particulates up to
particle sizes of 12µ and bag sizes from 1-5 litres
...
The bags are then cut from the web, filled and sealed
...
Both types of machines exist for filling particulates and also in packs
suitable for microwave heating
...


•

Bottles and Jars: Glass
bottles may be aseptically
filled with food containing
small particles, for instance
for baby food
...

In a recent development,
returnable bottles are filled
aseptically, which up to
now were applied only for
UHT – treated milk
...

Closing is usually done by heat-sealing aluminium lids
...


•

Metal Cans: As mentioned earlier, only the Dole system is able to apply to cans from steel
and aluminium for aseptic filling
...

315

•

Plastic Cans: An aseptic machine for filling and closing of two-piece plastic cans, ‘gourmet
cans’, was recently developed
...
They are sterilized with hydrogen peroxide, UV radiation and
heat-sealed inductively
...


•

Composite Cans: These may, at present, not be filled with particulate food, but only with
fruit juice with long fibers
...

• Physical integrity of the package is necessary to assume containment of the product and
maintenance of sterility
...

• The package must protect the product from oxygen, also package must retain the aroma of
the product
...
However, because plastic material is so important to aseptic packaging, it is
useful to discuss some special properties demanded of plastics by aseptic process itself
...
Hence the structure as well as composition of aseptic packaging are more complex
and vary depending on product application, package size and package type
...
Generally to
achieve all required properties, aseptic packages incorporate more than one material in the
structure that is assembled by lamination or co-extrusion process
...


Market Data on Packaging of Fruit Juices and Milk in Tetra Pak Packages
in India
This data is as compared to other packaging systems, based on 2002 data
...
A significant
portion (1/3rd) is retained at the farm level itself, and the balance is termed market milk
(roughly 55 billion litres)
...
27% of this liquid market milk is packed, the
balance is sold loose
...
Almost 58% is sold through the
500ml size, and 38% in 1000ml
...
4% or 0
...

Tetra Fino Aseptic
Tetra Classic Aseptic
The balance packed milk is
predominantly in Tetra Pak packages,
amounting to some 70 million litres,
although there is one player offering
white milk and flavoured milk in
aseptic plastic pouches in Delhi
...
Paine]

Aseptic (TCA) packages and the balance 14 million litres in the pouch-shaped Tetra Fino
Aseptic (TFA) carton-based packaging system (Figure 4)
...
are available either in (sterilized) glass bottles, or ordinary plastic pouches, or in Tetra
Pak packages
...
Milk production is
318

increasing at the rate of 4
...
While pasteurized milk in plastic pouches will
continue to grow (conversions from loose milk), white milk substitutes like milk powders
will actually lose market shares
...


•

Juices and Nectars: The packed juices and nectars market in India is around 33
...
Of this, 61% or 20
...
5% or 3
...
) in PET bottles
...
The
organized, packed juice market is still at a nascent stage, but reported to be growing at over
30% per annum
...
The branded juice market is reported to be worth Rs
...
There
is some amount of juice and nectars available in cans, but this segment is rapidly on the
decline
...


•

Juice Drinks: The packed juice drinks market in India is around 152 million litres
...
While juice drinks in glass
bottles account for 82
...
The
packaged juice drink segment is still only 6% of the total juice drinks market, estimated at
2400 million litres
...


Composition of Tetra Pak Aseptic Cartons
Tetra Pak aseptic cartons are made of three basic materials that together result in a
very efficient, safe and light-weight package
...

Figure 5: Composition of Tetrapak Aseptic Carton
1
...


Paper: For stability & strength

3
...


Aluminium: Oxygen, flavour & light

5
...


Polyethylene: Seals in the liquid

6 Layers Providing Total
Protection

319

• Paper (80%): to provide strength
•

•

and stiffness
Polyethylene (15%): to make
packages liquid tight and to
provide a barrier to microorganisms
Aluminium foil (5%): to keep
out air, light, and off-flavours
- all the things that can cause
food to deteriorate (Figure 6)

Figure 6: How is an Aseptic Carton Made
15%
Polyethylene

5%
Aluminium

80%
Paper board

Combining each of these three
materials has enabled Tetra Pak to produce a packaging material with optimal properties and
excellent performance characteristics (Figure 7)
...
The packages also have a variety of
openings and closures appropriate to product and consumer needs
...
Typical packaging
applications are:
• Fruit Juices, concentrates, purees
• Tomato Products
• Milk and Cream
• Coconut Products
• Jam
321

•

Working Principles of Bulk Filling Machine: The packages are manufactured from a
variety of laminates to match the product and required shelf-life
...
The inside of the package is
sterilized before delivery; the packages are supplied flat preventing the entry of air or
gas
...
All packages are intended to be
supported, when filled, by an outer container, for instance a drum or heavy-duty box
...

• No chemical sprays used to sterilize the chamber
...

• Safer sterilization and easier to monitor
...

• No risk of laminate material relating with chemicals

•

Reliability, because:
• The filling machine is uncomplicated as there is no sterile chamber
...
This ensures accuracy as no adjustments for specific
gravity need to be made
...


•

Extended Shelf-life due to:
• High oxygen barrier of the laminate
...

• Secure spout with limited possibility of oxygen permeation
...

• There is no head space in the bag
...


Bulk Aseptic Bags
A bulk aseptic bag is a multi-layer structure consisting of an outer barrier laminate and an inner
bag in contact with the product
...
The level of gamma irradiation is specifically selected to facilitate packaging of high as well
as low acid products
...

Aluminium foil as barrier material is used if the products are extremely sensitive to oxidation
and loss of aroma and is used in super barrier bags
...
The 1140 litres bag is
also available with separate emptying spout
...
Aseptic processing sterilizes food products by destroying
the harmful bacteria and pathogenic micro-organisms through a tightly controlled thermal
process and combines the sterile product with the sterile packaging material in a sterile
environment, the end result is a shelf-stable product requiring no refrigeration
...
Today, this is readily being used in the innermost
contact layers of the package, thereby protecting the quality of food
...


Aseptic Processing and Packaging of Particulate Food, Edited by Edward M
...
Willhoft

2
...
Reuter

3
...
76

4
...


The Wiley Encyclopedia of Packaging Technology

6
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Bern Hard Von Bookelmann,
A
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Tetra Pak, Lund, Sweden

7
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Paine

8
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tetrapak
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sgi
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hassia
...
packexpo
...
serac-group
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brevettiangela
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boschpackaging
...
indiadairy

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