ASO Co., Ltd.

Microorganisms are almost non-existent! Is it true?

In some cases, customers are told that the inner surface of plastic bags is ‘almost free of micro-organisms because the resin is melted at a high temperature (180 °C) in an inflation process’.

This is completely unfounded.

This is because polyethylene tubes are heated to approximately 180 °C, but the molten resin is blown up by air in the inflation process.

Therefore, the initial bubble in which the tube is made is trapped by the atmospheric air in the factory, while the air for adjusting the bubble is supplied by a compressor.

The temperature in the bubble is not at a temperature at which micro-organisms can be killed.

In short, the air that is not controlled is no different from that of products in the general environment.

Air used for normal inflation rarely has a sterilisable filter, which allows relatively large particles (5 µm, 10 µm) to enter the air.

It is therefore essential for pharmaceutical packaging that the inflation air must be filtered by a filter of at least 0.3 µm or less.

The surface of the bag is also contaminated by contact with various rolls such as nip roll and tension rolls in several processes, including inflation, bag-making and printing processes. These rolls are also significantly contaminated depending on the working atmosphere and cleaning standards of each process.

Therefore, the production environment, production operations and cleaning procedures have a major impact to products.