Managing crises with partners

Dr Stéphane Papilloud, Head of Safety for Food Packaging at Nestlé, told delegates in Stuttgart that the resulting demands on packaging of ‘food scares’ have noticeable economic consequences for the entire value chain. The discovery of migration of ITX or 4-methyl benzophenone irreversibly changed the world of packaging, he said. In the future, the food producer Nestlé will increasingly place emphasis on closer and better partnerships with supplying companies. From printing ink manufacturers, for example, the company is expecting affordable low-migration ink systems compliant with all applicable regulations.

In addition to the legal guidelines, Nestlé relies on company standards: four of the 25 subjects mentioned deal with printing inks for packaging. The standards refer to the printing of the outside of the packaging as well as the printing on the inside and to the processes of UV printing and inkjet.

But in every case, he added, very well controlled conditions are necessary, and Nestlé supports the Swiss Act for Printing Inks, which the company wants to establish as a worldwide standard supported by other manufacturers of branded goods.

Mr Papilloud favours the use of UV inks because he thinks that radiation curing ink systems are currently much better researched than solvent or water-based inks. Inks containing mineral oil do not have a future in the field of food packaging, in his opinion.

Is it safe to switch?

It is better not to switch between low-migration and standard production, say experts.

Zeller+Gmelin has carried out tests with the press manufacturer Müller Martini, the foil supplier Ineos Films and the supplier of print rollers Böttcher, to find answers to queries about the changeover to low-migration printing inks. For instance, are new rollers necessary for the changeover on an offset press, does the fountain solution have to be replaced or does an alternating operation make any sense at all?

In fact, with the five tested cleaning methods, all of which proved labour intensive, one proved to be suitable for an alternating operation. Nevertheless, Zeller+Gmelin advises against alternating between low-migration and standard printing inks, as the risks for contamination or carelessness are rated as too high. As a consequence it is believed that low-migration production is not compatible with an alternating operation in the daily routine of a printing shop.

Furthermore, the full cure of the ink or varnish layer is indispensable for low-migration production, and the supervision and control of the UV-system must be adopted as a general rule for UV printing.

The migration behaviour of pressure sensitive adhesives should also be considered.

According to Dr Ulli Nägele, Head of Development and Application Technology at Herma, only acrylate-based adhesives can be recommended for a direct contact with fatty food. Rubber-based hotmelt adhesives are ‘absolutely unsuitable’ for this purpose, he says.

Moreover, Dr Nägele points to the fact that migration can also take place in the opposite direction. Oils, surfactants and plasticisers migrating from the filling through the packaging ‘soften’ the pressure sensitive adhesive, and may result in blistering or a peeling of the corners of the label.