Food Thermal Labels are a Source of Dietary Exposure to Bisphenol S and Other Color Developers

06 January 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


To test the hypothesis that migration from the thermal labels on plastic film packaging is a major source of exposure to bisphenols and alternative color developers in food, we analyzed 140 packaging materials from packaged fresh food purchased in North America. No bisphenol A (BPA) was detected in either the packaging samples or thermal labels. However, significant amounts of bisphenol S (BPS) and alternative color developers (up to 214 μg/cm2) were present in thermal labels; their relative occurrence varied among stores. In a controlled experiment, we wrapped fish in film with a thermal label for five days at 4℃. The fish in contact with the label contained BPS (≤ 1140 ng/g wet weight [ww]), 4-hydroxyphenyl 4-isoprooxyphenylsulfone (D-8) (≤ 230 ng/g ww), bis(2-chloroethyl)ether-4,400-dihydroxydiphenyl sulfone monomer (D-90) (≤ 3.41 ng/g ww), and Pergafast-201 (≤ 1.87 ng/g ww). This study provides evidence, for the first time, that BPS and alternative thermal label color developers migrate from packaging materials into food. Further, BPS migration significantly exceeded the European Union Specific Migration Limit (50 ng/g ww), suggesting that further risk assessment studies are warranted.


Bisphenol analogues
Endocrine disrupting chemicals
Food contact material
Thermal labels
Food packaging

Supplementary materials

Supplemental Material
This files contains Supplemental Figures S1-S12 and Supplemental Tables S1-S9


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