In an article published on March 15, 2023, in the journal Environmental Science & Technology, Ziyun Xu and co-authors from McGill University, Montreal, Canada, analyzed the migration into fresh foodstuffs of bisphenol S (BPS, CAS 80-09-1) and other color developers from 140 food packaging items and the thermal labels pasted onto the packaging. BPS is commonly used as a substitute for bisphenol A (BPA; CAS 80-05-07) since the latter is generally recognized for its toxic effects, e.g., it was classified as a substance of very high concern (SVHC) due to its endocrine disrupting properties (FPF reported). However, BPS has also been connected to adverse health outcomes (FPF reported, here, and here), found to migrate from food packaging (FPF reported), and detected in foods such as Canadian meat products (FPF reported).
To evaluate if the chemical migration of BPS and other color developers from food packaging and labels contributes to dietary exposure to these compounds, Xu and co-authors purchased 140 food packaging samples, including plastic films, pads, styrofoam trays, and labels (price tags and other stickers) in supermarkets in Montreal, Canada, and the US and incubated them for 10 days in 95% ethanol at 20 °C. In addition, the scientists acquired 24 packaged fish fillets and assessed them and the labels and films they were in contact with for 5 days at 4 °C. To investigate bisphenols and their alternatives, samples were applied to liquid chromatography quadrupole time-of-flight mass spectrometry (LC−QToFMS).
The researchers detected BPS in 29 out of 40 thermal price labels, 6 out of 29 nonprice labels, and 11 out of 39 plain films with concentrations up to 193 mg/cm² in the labels. On the contrary, BPA was not found in any of the 140 samples. Other color developers detected in thermal price labels above the limit of detection were 4-hydroxyphenyl 4-isoprooxyphenylsulfone (D-8), bis(2-chloroethyl)ether-4,4’-dihydroxydiphenyl sulfone monomer (D-90, CAS 191680-83-8), bis(3-allyl-4-hydroxyphenyl) sulfone (TGSA, CAS 41481-66-7), and pergafast-201 (CAS 232938-43-1). The occurrence of color developers varied between the stores “suggesting that the use of specific color developers in the manufacture of thermal labels is quite variable.”
Looking at the fish in contact with the labels, the authors reported that they contained up to 1149 ng/g wet weight (ww) BPS, 230 ng/g ww D-8, 3.41 ng/g ww D-90, and up to 1.87 ng/g ww Pergadas-201. While Canada currently does not regulate BPS, the chemical concentration in the fish exceeded the migration limit set by the European Union for food packaging materials. The migration of BPS from the films in contact with fish was found to be significantly higher for those with thermal labels than those without. As a hypothetical migration pathway for the thermal label color developers, the authors proposed that “BPS, D-8, D-90, and PF-201 diffuse from the thermal layer of the paper across the adhesive layer and the cling film to reach the fish matrix.”
Given their results, the authors emphasized “the need to include nontargeted analysis in food surveillance to help identify unknown or unexpected contaminants, like new color developers.”
İsra Toptancı from the Food Control Laboratory, Istanbul, Turkey, recently studied the presence of BPS and other bisphenols (BPA, BPF, BPB) as well as of bisphenol A diglycidyl ether (BADGE, CAS 1675–54-3), and its derivatives in canned food. In her research published on March 4, 2023, in the journal Environmental Science and Pollution Research, she analyzed 54 convenience foods (i.e., “traditional Turkish ready to eat meals”), 4 vegetable oils, 4 olive oils, and 17 soft drink samples purchased in Turkey. BPS was detected in six out of the 79 analyzed foods in concentrations of up to 0.036 mg/kg food. In contrast to the Canadian samples investigated by Xu and co-authors, BPA was the most frequently detected bisphenol, i.e., in 57% of the samples. Levels reached up to 0.102 mg/kg while those of BPF and BPB reached 0.021 and 0.072 mg/kg, respectively.
There is an ongoing public consultation for a proposed EU-wide restriction on bisphenols under REACH which accepts comments until June 22, 2023 (FPF reported).
References
Xu, Z. et al. (2023). “Food Thermal Labels are a Source of Dietary Exposure to Bisphenol S and Other Color Developers.” Environmental Science & Technology. DOI: 10.1021/acs.est.2c09390
Toptancı, İ. (2023). “Risk assessment of bisphenol related compounds in canned convenience foods, olives, olive oil, and canned soft drinks in Turkey.” Environmental Science and Pollution Research. DOI: 10.1007/s11356-023-26228-6
Read more
Shirley Cardenas (March 16, 2023). “Fresh produce contaminated with toxic BPA-like chemicals found in food labels, study finds.” McGill
