The food industry employs pasteurisation in order to extend the shelf life of products. This process destroys harmful bacteria that cause food products to spoil rapidly. In 1862 Louis Pasteur discovered that briefly subjecting the product to heat would suffice in neutralising this threat. As opposed to sterilisation, this technique does not actually destroy all microorganisms, but instead reduces their numbers to such a low level that they are no longer able to cause disease.
The processing time of pasteurisation varies from a few minutes to as much as a few hours, at a temperature of approximately 85 °C. This process is usually carried out under conditions of 100% humidity by immersing the packaging, for example, or by treating it with steam. Needless to say, pasteurisation has its impact on the ink and the lacquers of IML labels. It is the combination of high temperatures and high humidity in particular that is damaging to the ink and the lacquer.
To prevent a label from ‘bleeding’ (i.e. the running of magenta ink) during pasteurisation, or from developing white blotches as a result of damage to the lacquer, Printing Company Verstraete has developed a specific combination of inks along with a special lacquer. This produces labels that retain their quality and appearance, even after the IML packaging containers have been pasteurised.
Practically speaking, Printing Company Verstraete only needs to make use of the special inks and lacquer on the container label itself, because most manufacturers pasteurise their packaging without the lid.
It is also important to be aware of the existence of pasteurisation methods that make use of microwaves, ultrahigh pressure or supercritical CO2. Some of these alternative methods make no use of water or steam whatsoever. Special inks or lacquers are not required when this type of ‘dry process’ is employed.
In the dishwasher reusable containers are exposed to 100% humidity and high temperatures - just as with pasteurisation. The effect of detergents must also be taken into account. Up until recently the use of a primer and a UV lacquer was required in order to produce dishwasher-resistant labels, which in turn rendered a high-gloss effect. Thanks to the combination of special inks and lacquers, these dishwasher-safe labels are now also available without this high-gloss effect.
In short, Printing Company Verstraete can also offer you IML labels as a decoration technique for the production of semi-durable and dishwasher-resistant products, such as drink cups, measuring jugs and lunchboxes.
For more information on pasteurisation- and dishwashersafe labels, please email firstname.lastname@example.org.