Packaging of Dairy Products

Module 9. Aseptic packaging

Lesson 28
SCOPE OF ASEPTIC PACKAGING AND PRE-REQUISITE CONDITIONS FOR ASEPTIC PACKAGING. DESCRIPTION OF EQUIPMENTS (INCLUDING ASEPTIC TANK) AND MACHINES

28.1 Introduction

Aseptic 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 re-infection is prevented. This results in a product, which is shelf-stable at ambient temperature conditions.

28.2 Scope of Aseptic Packaging

There are number of limitations and disadvantages during actual application of this technology. However, we can’t ignore the advantages over various lacunas of the process. Thus, it can be concluded that aseptic packaging of sterile/non sterile food and food products is the most significant innovation in the field of food science and technology and there is a big scope in this area.

28.3 Major Categories of Aseptic Packaging Systems

• Can system: It includes hermetically sealed cans.

• Bottle systems: Glass containers and plastics bottles fall into this category. The bottles can further be divided into; a) Non-sterile bottles; b) Sterile blown bottles; c) Single station blowing, filling & sealing.

• Sachet and pouch systems: This system is classified into Form-fill-seal systems and Lay flat tubing.

• Cup systems: The aseptic packaging of food into cups can be into; Pre-formed plastic cups and Form-fill and seal cups.

• Carton systems: This type of aseptic packaging system includes Form-fill-seal cartons and Prefabricated cartons.

• Bulk packaging systems: This type of system classified into; Metal drum and Bag-in-box Packaging Lines for Aseptic Processing.
  

There are five basic types of aseptic packaging lines as given below;

• Film & Seal: Pre-formed containers made up of thermoformed plastic, glass or metal are sterilized, filled in aseptic environment and sealed.

• Form, Fill & Seal: Roll of material is sterilized, formed in sterile environment, filled and sealed. e.g. Ex tetra packs Erect, Fill & seal: Using knocked, down blanks, erected, sterilized, filled sealed. e.g. Ex. Gable-top cartons, Cambri-block.

• Thermoform, Fill, sealed roll stock, sterilized, thermoformed, filled, sealed aseptically. e.g. Ex. Creamers, plastic soup cans.

• Blow, Mold, Fill & Seal. e.g. Different package forms used in Aseptic UHT processing are cans, paperboards/plastic/foil/plastic laminates/flexible pouches, thermoformed plastic containers, bag in box, bulk totes.

28.4 Pre-Requisite Conditions for Aseptic Packaging

• It should contain the product.

• It should prevent physical damage to packaged product.

• It should run smoothly on filling lines.

• It should withstand packaging processes.

• It should be easy to handle throughout distribution process.

• It should prevent dirt and other contamination.

• It should be able to protect the product from odours and taints.

• It should be resistant to rodent attack.

• It should be able to stop insect infestation.

• It should be biologically safe i.e. non toxic.

• It should be compatible to foodstuff.

• It should provide sterility to product.

• It should prevent ingress of microorganisms.

• It should show evidence of tampering.

• It should control moisture loss or gain.

• It should offer a barrier to oxygen.

• It should be protective against the light.

• It should maintain gas atmospheres, i.e. CO₂/N₂.

• It should communicate all the information regarding product and manufacturer.

• It should have good sales appeal.

• It should be easy to open

• It should be cost effective

The above given pack criteria are separated into seven areas, mainly as follows:

• Product containment: The need to contain the product in the sense that liquids or powders do not leak out.

• Physical protection: This is required when dealing with fragile foods like eggs or snack foods, but minor impacts on fresh fruits, for example, will release enzymes and lead to browning and softening. Equally important is the adverse effects on sales of damaged packages themselves-even though the product is in good condition.

• Food safety: The need to ensure that the aseptically packed food retains its sterility, through a package that prevents adventitious contamination by microorganisms. Tamper evidence is also a desirable requirement. The other aspect of food safety is the avoidance of long-term chronic effects from the food packaging materials themselves.

• Shelf-life: For dried foods moisture gain is a major factor in determining shelf-life. Atmospheric oxidation, often catalyzed by light, is more critical for aseptically packed foods such as milk, fruit juices, or cream soups. Hence a good oxygen and light barrier, as provided by tinplate or aluminum foil, is needed to ensure maximum shelf life for aseptically packed products.

• Communication of information: The package should need to tell the purchaser what food is inside it and whose product it is. Apart from this, more information should be passed on to the customer, such as net weight, list of ingredients, batch number, use-by date, nutritional information etc.

• Sale-appeal: The package must look attractive and ‘catch the eye’ of prospective purchasers, and it should also be easy to open and dispense the product.

• Cost-effectiveness: Value for money in packaging is more important than looking for the lowest price. A cheap but dimensionally variable container could cause more damage during production or an increase of ‘leakers’ in the market place, thereby effects the sale of the product.

28.5 Aseptic Tank

The aseptic tank is used for intermediate storage of UHT treated dairy products. It can be used in different ways in UHT lines, depending on plant design and the capacities of the various units in the process and packaging lines.

• If one of the packaging machines incidentally stops, the aseptic tank can take care of the surplus product during the stoppage.

• Simultaneous packaging of two products.

The aseptic tank is first filled with one product, sufficient to last for a full shift of packaging. Then the UHT plant is switched over to another product which is packed directly in the line of packaging machines. One or more aseptic tanks included in the production line offer flexibility in production planning.

Direct packaging from a UHT plant requires recirculation of a minimum extra volume of 300 litres per hour to maintain a constant pressure to the filling machines. Products which are sensitive to overtreatment cannot tolerate this and the required overcapacity must then be fed from an aseptic tank.

The optimum arrangement must thus be decided for each individual process with UHT plants, aseptic tanks and aseptic packaging machines.