Colourful and eye-catching food packaging is what makes a product sell. Well-designed paper packaging is also essential for food producers as it is lightweight, saves space when stacked and allows for cost-effective transportation to its final destination. It also protects the products against moisture, contamination and damage.
However, many food products are enveloped in protective paper made from recycled waste paper, such as newspapers, which can contain residues of newspaper printing inks and mineral oils not approved for food contact. These mineral oils cannot be completely removed in the recycling process and consequently enter the packaging. This process of food contamination, called migration, can occur even without direct contact between the cardboard and the food.
“Studies by the official Food Safety Authority of the Canton of Zurich have shown that about 30% of all migratable substances have entered the food after two months at room temperature,” explains Heiko Diehl, member of BASF’s Packaging Network Team.
“Once the contaminants have accumulated in the food, they can no longer be removed or made safe by washing or boiling,” adds Diehl.
According to the press release by BASF, the company came up with a coating solution to protect the foods from these substances. The BASF team developed various barrier solutions that are applied to the internal surface of the cardboard box. These extremely thin coatings are made from polymers, in other words macromolecules made up of many repeating smaller molecules. Barrier coatings that are only 10 to 15 micrometres thick– by comparison, a hair is 120 micrometres thick– already protect food from the contaminants for up to three years. Products like noodles that remain for an average of 15 to 24 months in the packages, are thereby reliably protected.
“The most important requirement for the barriers is that the breakthrough time – which is the period until a barrier can become permeable and allow health hazardous substances to penetrate into the food – is longer than the shelf-life of the packaged product,” explains Diehl.
“Our barrier coatings can be imagined as being like a close meshwork that allows only certain molecules to pass through,” continues Diehl.
According to him, the barrier effect can only be penetrated by very small molecules, like water vapour, while larger molecules like mineral oil residues cannot cross.
“The coating simultaneously has to be flexible enough to prevent fractures forming when folding the cardboard ensuring the barrier remains intact,” says Dr Carmen Cimpeanu of BASF Materials and Systems Research.
BASF is the world’s leading chemical company that promotes environmental protection and social responsibility. The company employs more than 112,000 workers across its six Germany-based Verbund sites and 376 additional production sites scattered all over the world.