March 11, 2014 Pirita Suortamo
Since 2009, a widely discussed topic in Europe has been harmful mineral oils found in food in recycled fibre based packages. The conclusion is that mineral oils have migrated from the packages into the food. This phenomenon is called ‘direct migration’. Another possible form of migration is ‘indirect migration’, where the assumption is that mineral oils migrate from recycled fibre based transport packages, through the food package, and into the food itself.
The main source of harmful mineral oils in recycled fibre is the inks used for printing newspapers. As a result, recycled fibre packaging materials contain significant amounts of mineral oils.
Metsä Board’s folding boxboards are manufactured from fresh forest fibres which are clean by nature and their chemical composition is known. They are approved for direct food contact and may be safely used as primary packaging of food products.
Metsä Board did, however, want to establish whether it should be worried about possible contamination from transport packaging containing recycled fibre.
Set-up of the indirect migration study
In order to find out the risk of indirect migration from transport packaging, a study (see the link on right) was carried out where mineral oil content, both in dry food and in packaging materials, was measured after one, two, five, seven and 11 months storage time. Fresh forest fibre based folding boxboard cartons were packed in a corrugated box made of recycled fibres. The food itself within the cartons was packed in high density polyethylene (HDPE) bags. All dry food samples were received direct from the customer’s mill, and stored in their original packages. They were then compared to an unpacked sample of the same food, which had been wrapped in aluminium to protect it from any external contamination.
The mineral oil analyses were made at an independent accredited laboratory in Germany by utilising the BfR method. The study was designed to replicate real warehouse or supermarket storage conditions.
No indirect migration found
During the storage time of 11 months, using real food samples in a simulation of real storage conditions, there was no increase in harmful mineral oil content either in the food or in the cartons.This was also proven by analysing the same type of product purchased from a local supermarket – one that had gone through the whole transportation chain.
There remain, however, concerns over direct migration. When food is packed in cartons made of recycled fibres the risk of harmful mineral oil migration exists. To avoid this risk only fresh fibre based board is recommended. It is also important to pay attention to other packaging components and to make use of the best possible design to avoid migration.