Chlorinated paraffins – the latest contaminant of concern
Dr. rer. nat. Kerstin Krätschmer, Project Leader Scientist, Wageningen Food Safety Research, the Netherlands

Chlorinated paraffins (CPs) are high production volume chemicals of growing concern that have been found in the environment, food and humans. These cheap-to-produce plasticizers and flame retardants are very complex mixtures of primarily polychlorinated alkanes (PCAs) [1]. Similar to dioxins and other contaminants, PCAs can accumulate especially in products with high fat content. Additionally, PCAs can also be added unintentionally during food processing, e.g. if parts of the machinery are lubricated with a CP product.

Based on earlier PCA findings in vegetable oils sold in Europe, we collected and analysed 94 oils and 20 spreads from the Dutch market. Additionally, removal of PCAs during oil refinement was investigated in 13 paired crude and refined vegetable oils from a Dutch contract refining company [2].

In 81 out of 94 vegetable oil samples, mainly medium-chain (C14-C17-)PCAs were found, with the highest sample reaching a measured overall PCA content of 6000 ng/g (mean: 610 ng/g). Remarkably, the 16 analysed palm oils of that set reached on average 1370 ng/g PCAs, and were in contrast to the general findings often dominated by short-chain (C10-C13-)PCAs. Most of these palm oil samples were unrefined or cold-filtered products.

The highest PCA levels in European oils were found in extra virgin olive oils, the lowest in highly refined rapeseed oils. In accordance with these observations, the paired refined samples had 60-80% lower short- and medium-chain PCA content than their crude counterparts. The spreads were overall much lower in PCA content than the oils. Interestingly, they followed the concentration trend of the oils somewhat with higher medium chain PCA levels in products containing palm oil than in the palm oil free versions.

While oil refinement seems a good way to reduce PCA contamination, especially unrefined oils should still be considered important dietary sources of PCAs.

[1] Fernandes et al. (2023), TrAC 169, 117363.

[2] Shen et al. (2023), Food Cont. 153, 109889.