In an article published on December 16, 2021, in the journal Molecules, Pablo Miralles and co-authors from the Foundation for the Promotion of Health and Biomedical Research in the Valencian Region (FISABIO), Valencia, Spain, determined migrating substances from four plastic food contact articles made of different polymers. The researchers developed a method that starts with migration experiments according to Commission Regulation (EU) 10/2011 with four food simulants and continues with vortex-assisted liquid-liquid extraction with n-hexane as a solvent, before samples are then applied to high-resolution gas chromatography coupled to mass spectrometry (GC-HRMS). When applying the developed method to the four samples, they did not detect any of the 60 analyzed chemicals (e.g., phthalates, plasticizers, aldehydes, and ketones) in concentrations above the method’s level of quantification. Thus, Miralles and colleagues concluded that the products “complied with the current European regulation regarding the studied substances.” However, they proposed to apply the methodology to a larger sample set “to obtain data regarding the appearance rate of the studied substances as market surveillance.”
While they looked at known chemicals in this recent study, the same authors also analyzed unknown compounds in recycled plastic in an earlier study published in November 2021. There they detected over 300 chemical features of which they identified 83 (FPF reported).
Another study published on December 16, 2021, in the journal Food Additives & Contaminants: Part A analyzed styrene (CAS 100-42-5) monomers migrating from polystyrene (PS) food contact materials (FCMs). Stella Kontou and co-authors from the Food Contact Materials Laboratory, Athens, Greece, developed a fast headspace – solid-phase microextraction – gas chromatography – tandem mass spectrometry method (HS-SPME-GC-MS/MS) for styrene determination in different food matrices. Kontou and colleagues applied the method to 37 samples of foodstuffs packaged in PS containers or in contact with PS kitchen- or tableware articles available on the Greek market. They found 0.4 to 160 ng/g styrene migrating from the packages. In 56% of the dairy products and desserts, styrene concentrations exceeded 10 ng/g while the highest concentration was detected in meat packaged in foamed PS. The authors further reported higher styrene migration in milk than water as well as higher levels in products near their expiring date and products with longer shelf-life. The potential exposure of the Greek population to styrene originating from the different PS FCMs was also calculated and found to range from 25.3 to 89.2 ng/g foodstuff for hot drinks served in foamed PS cups and to be 22.5 ng/g foodstuff for dairy products and desserts packed in PS containers.
In 2016, the US State of California added styrene to its Proposition 65 list of carcinogens (FPF reported), and in 2018 the International Agency for Research on Cancer (IARC) concluded that styrene is “probably carcinogenic to humans” (FPF reported).
In an article published on December 31, 2021, in the peer-reviewed journal Food Chemistry, Qiuju Liang and co-authors from the Technology Center of China Tobacco Hunan Industrial Co. and Central South University, Changsha, China, presented a rapid high throughput method for the quantitative and simultaneous determination of several photoinitiators (PIs) in paper FCMs. The authors outlined how they developed and optimized the so-called FastPrep-based extraction method where the PIs are extracted from the samples in only 60 seconds by the application of mechanical force. Subsequently, they used this method coupled to gas chromatography-mass spectrometry to analyze twenty different paper FCMs for 18 PIs including several benzophenones. Liang et al. found seven samples to contain PIs, including paper cups as well as milk, biscuit, and toothpaste paper packaging. Overall, they detected seven of the 18 analyzed PIs, and amounts of the individual compounds ranged from 1 to 195 mg/kg. The authors reported that “some of the detected PIs are strictly prohibited for use in the energy curing inks of food paper packaging materials since they may cause a severe threat to health.”
The primary source of photoinitiators in FCMs is printing inks, and they have been found in paper straws (FPF reported) and other paper and board food packaging (FPF reported). In November 2021, the German Federal Council adopted the 21st Amendment to the Consumer Goods Ordinance regulating printing inks and varnishes that directly or indirectly contact food, including an update of PIs on its positive list (FPF reported).
In a study published on December 31, 2021, in the Journal of Hazardous Materials, Yujiao Wang from China Agricultural University, Beijing, China, and co-authors investigated 107 green tea and 19 tea packaging samples for the presence and migration of short-chain chlorinated paraffins (CAS 85535-84-8) and medium-chain chlorinated paraffins (CAS 85535-85-9). The tea samples were collected from eleven Chinese provinces with packaging composed of polyethylene (PE), polypropylene (PP), PP non-woven, paper, and aluminum. Using two-dimensional gas chromatography (GC×GC-MS/MS) for chemical analysis, the authors detected between 4.99 and 717 ng/g short-chain and between 2.55 and 543 ng/g medium-chain chlorinated paraffins in the analyzed green tea samples. Province-related differences in the levels were not identified. The scientists further extracted 19 tea packaging samples and reported chlorinated paraffins in concentrations of up to 3858 ng/g. Migration experiments showed that the chlorinated paraffins transferred from the packaging into the tea with the small-chain compounds migrating faster than the medium-chain congeners. Wang and co-authors also reported that the concentration of chlorinated paraffins in the packaging affected the compounds’ concentrations in the tea sample. This made them suggest “to monitor and regulate the content of chlorinated paraffins in both tea and packaging materials, in order to ensure tea production quality and consumer safety.”
In March 2020, the European Food Safety Authority (EFSA) published its risk assessment of chlorinated paraffins in feed and food finding insufficient data to complete robust risk characterization such that a non-health-based guidance value was defined (FPF reported). In July, 2021, medium-chain chlorinated paraffins were added to the European Chemicals Agency’s (ECHA) Candidate List for substances of very high concern (SVHCs) (FPF reported).
In a research article published on December 30, 2021, in the journal Food Packaging and Shelf Life, Hong Zhang from the Chinese Academy of Agricultural Sciences, Beijing, China, and co-authors analyzed whether irradiation affects chemical migration. Food irradiation is one technology used for food preservation. In spring 2020, the European Commission (EC) consulted on the ongoing evaluation of EU legislation related to irradiation of food and food ingredients (FPF reported). Zhang and co-authors investigated the chemicals migrating from metalized polypropylene (met PP) film with and without irradiation treatment into a food simulant (95% ethanol) using liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF/MS). Met PP is “a relatively new type of packaging material” where the aluminum is directly applied on the PP without the use of adhesives but by vacuum deposition.
The authors identified a total of eleven compounds migrating from the films over 21 days. All of them were antioxidants or their derivates, including Irganox 1076 (CAS 2082-79-3) and Irganox 1010 (CAS 6683-19-8) as well as Irgafos 168 (CAS 31570-04-4). While three of the eleven compounds were intentionally added substances (IAS), the remaining were considered to be non-intentionally added substances (NIAS) also including radiolysis products. Five chemicals (three hindered phenolic compounds, one phosphate, and one phosphonate compound) tested after film treatment with gamma and electron beam irradiation showed that migration levels decreased upon the treatment. Hereby, the researchers found that the lower the stability of the chemical under irradiation the more similar the migration rate compared to that from untreated met PP. Zhang et al. further evaluated the potential risk of met PP films based on the migration limits of selected chemicals and reported that the “migration level of the phosphonate compound was above the recommended migration limit, which may present a safety concern.” The authors concluded that irradiation treatment in their study did not lead to an increase in migration and that “attention needs to be paid to NIAS (including radiolysis products) in packaging materials due to the lack of information on their potential risks.”
References
Kontou, S. et al. (2021). “Determination of styrene monomer migrating in foodstuffs from polystyrene food contact articles using HS-SPME-GC-MS/MS: Results from the Greek market.” Food Additives & Contaminants: Part A. DOI: 10.1080/19440049.2021.2005830
Liang, Q. et al. (2021). “Determination of 18 photoinitiators in food paper packaging materials by FastPrep-based extraction combined with GC–MS.” Food Chemistry. DOI: 10.1016/j.foodchem.2021.131980
Miralles, P. et al. (2021). “Determination of 60 Migrant Substances in Plastic Food Contact Materials by Vortex-Assisted Liquid-Liquid Extraction and GC-Q-Orbitrap HRMS.” Molecules. DOI: 10.3390/molecules26247640
Wang Y. et al. (2021). “Short- and medium-chain chlorinated paraffins in green tea from 11 Chinese provinces and their migration from packaging.” Journal of Hazardous Materials. DOI: 10.1016/j.jhazmat.2021.128192
Zhang H. et al. (2021). “Migration testing of metallized polypropylene films treated with ionizing radiation.” Food Packaging and Shelf Life. DOI: 10.1016/j.fpsl.2021.100799
