In an article published online on June 22, 2021, in the peer-reviewed journal Food Additives & Contaminants: Part A, Erica Selin from the Swedish University of Agricultural Sciences, Uppsala, Sweden, and co-authors extracted 67 food contact materials (FCMs) made of paper and cardboard with methanol and analyzed the effects of extracted chemical mixtures on endpoints relevant to human health using cell-based bioassays.
For their study, the scientists purchased 67 commonly used paper and cardboard products on the Swedish market and pooled similar FCMs into 23 groups, including pizza boxes, bags for cookies, and straws. They extracted 1 g of the products (except paper for baking and baking molds) with methanol for 20 min at 80 °C followed by ultrasonication for 15 min to isolate water-soluble, and to some extent fat-soluble, chemicals. The resulting extracts were applied to seven in vitro bioassays for investigating oxidative stress (Nrf2 activity), genotoxicity (micronucleus test), inflammatory response (NFκβ activation), xenobiotic metabolism (AhR activation), estrogenic and antiestrogenic effects (ER), as well as androgenic and antiandrogenic effects (AR).
At the highest applied concentration (10 mg/mL), all 23 samples induced a genotoxic response, 52% induced oxidative stress, 74% affected the xenobiotic metabolism, 52% inhibited the human androgen receptor, and 39% the estrogen receptor. Selin and colleagues hypothesized that natural components within the paper or board as well as coatings, inks, and contaminants may be responsible for observed in vitro toxicities. They considered “cake/pastry boxes/mats, boxes for infant formula/skimmed milk, pizza boxes, pizza slice trays and bag of cookies” as packages of potential concern.
The authors emphasize that by using methanol, ultrasound, and high temperatures they performed an extraction relevant for some materials, such as microwave popcorn bags that are exposed to high temperatures, while for other products that method might exaggerate realistic migration. They further highlight that “an effect-based approach enables hazard identification of chemicals” used in FCMs by taking known and unknown compounds, as well as mixture toxicities into account (FPF reported).
Selin, E. et al. (2021). “Food contact materials: an effect-based evaluation of the presence of hazardous chemicals in paper and cardboard packaging.” Food Packaging and Shelf Life (published online June 22, 2021).