PACKAGING OF DAIRY PRODUCTS

Module 9. Aseptic packaging

Lesson 29
MICRO-PROCESSOR CONTROLLED SYSTEMS EMPLOYED FOR ASEPTIC PACKAGING - PACKAGE CONDITIONS AND QUALITY ASSURANCE ASPECTS OF ASEPTIC PACKAGING

29.1 Introduction

Microprocessors & microcomputers are first used in packaging machines for the first time in 1973. Microprocessor-based equipment controls were first used in 1977. Microprocessor-controlled packaging machinery were first commercially used in 1978. Microprocessor-based aseptic packaging has capability of monitoring one or more process variables simultaneously.

Main operations that are taken care by microprocessors are

• Feeding of film to the machine

• Converting of film into required shape of specific dimensions

• Filling the product with specific volume of product

• Heat sealing

• Collecting up of specific no of packs and shrink wrapping them into one single pack.

All these operations are taken care by Microprocessors.

29.2 Sterilization of Packaging Material

Whatever the choice of packaging material used, it must be pre-sterilized prior to filling. Sterilization of the packaging material should not impair that material. Methods commonly used for sterilization of packaging materials or packages include steam (saturated or superheated), hot air, hydrogen peroxide, ultraviolet light, irradiation, or the heat generated during the co-extrusion of certain films.

29.2.1 Precautions to be taken

Since aseptic packaging systems are complex, there is considerable scope for packaging faults to occur, which will lead to spoiled products.

• Packages should be inspected regularly to ensure that they are airtight, again focusing upon those more critical parts of the process, such as start-up, shutdown, product changeovers and, for carton systems, reel splices and paper splices.

• Pipes, storage tank, and surfaces of the packaging machine come into contact with the sterilized product have to be sterilized.

• Sterilization procedures should be verified.

• The seal integrity of the package should be monitored as well as the overall microbial quality of packaging material itself.

• Care should be taken to minimize contamination during subsequent handling. All these could result in an increase in spoilage rate.

• Rinsing, cleaning and disinfecting procedures are also very important, especially the removal of fouling deposits, which may provide a breeding ground for the growth of micro-organisms, especially thermofiles.

29.3 Quality Assurance Aspects of Aseptic Packaging

• Aseptic packaging has to be meticulously checked.

• Not only must the packaged product be examined, but so must all preceding steps, as well as the operators, which are potential carriers of pathogens.

• If just one bacterium reaches the product, and that bacterium is pathogenic and can proliferate (for example, Staphylococcus aureus), the result could be disastrous.

• In addition to regular sampling during production, further samples should be taken at the times or in situations known to be associated with an increased risk of contamination.

It is advisable to incubate these samples long enough, in most cases from 5 to 7 days at 30°C to allow sub-lethally damaged bacteria also to grow to detectable counts. The products should only be delivered if the result of the shelf-life test is Satisfactory