The ink undergoes a colour change from black to blue at retort temperature. It has an operating temperature from 5-40°C
A thermochromic ink that changes colour at high temperatures now offers food manufacturers a reliable coding method with an obvious colour change to indicate correct sterilisation of packaged food products, manufacturer Markem-Imaje says.
Designed for retort sterilisation of filled cans or plastic pouches, the ink changes from black to blue when the food package reaches the correct temperature of between 115 and 125°C.
With the growing regulatory demands by governments for proper coding and marking on cooked food products, there’s growing interest in product authenticity and quality assurance.
Thermochromic inks that change color when the treated product reaches the required temperature support this need. While thermochromic inks cannot guarantee that sterilisation has actually occurred, they assist manufacturers by providing a good indication that the process has taken place.
Markem-Imaje’s MS596 thermochromic ink can be used to print on both metal cans and plastic film and no pre- or post-treatment of the packaging material is required.
Unlike some earlier generations of thermochromic ink, Markem-Imaje says, the product will not change colour prematurely due to temperature effects from the printer itself, rather than the sterilisation process.
It features a drying time of only one second on all materials. MS596 reportedly resists smearing to maintain high coding legibility and is less affected by oil and grease residues or water during the retort process.
Given this ink can come into contact with food, all raw materials used to create it have been chosen in line with the Swiss Ordinance which helps ensure inks are safe to use in such situations.
The ink is formulated and manufactured in accordance with the EuPIA (European Printing Ink Association) “Guideline on printing inks applied to the non-food contact surface of food packaging materials and articles” and complies with the EuPIA Exclusion Policy.
It does not feature ingredients dangerous to aquatic life nor does it contain methanol which is known to be highly toxic to the human nervous system.