In an article published on July 6, 2022, in the Journal of Agricultural and Food Chemistry, Xin Wang and co-authors from the Chinese Academy of Sciences, Beijing, China, assessed organophosphate ester (OPE) contamination of Chinese foodstuff and evaluated whether the chemicals originated from the packaging. OPEs are used as flame retardants and may also act as plasticizers.
In 2019, the authors acquired 229 packaged food samples from ten provinces across China covering 12 categories of food. To determine organophosphate levels, they developed and applied a new two-stage solid-phase extraction method and coupled it with ultra-high performance liquid chromatography mass spectrometry (UPLC-MS/MS). Besides the food, they also analyzed 50 packaging materials made of different polymers and food additives for the presence of organophosphate esters to investigate potential contamination sources.
Wang and co-authors detected OPEs in all packaged food samples in total concentrations of 0.212 to 273 ng/g wet weight (ww) of food samples. Eight of the 14 analytes were present in 50% of the samples. Triphenyl phosphate (TPhP, CAS 115-86-6), tris(2-chloroisopropyl) phosphate (TCIPP, CAS 13674-84-5), and tris(2-chloroisopropyl) phosphate (TCEP, CAS 51805-45-9) were the OPEs with the highest levels in most of the 12 food categories.
Comparing the levels of OPEs in packaged food with those in fresh food, the scientists reported that higher levels of OPEs were detected in the packaged food than fresh foods (fruits and meat), letting them hypothesize that during food processing and storage OPEs are introduced in the foodstuff. OPE levels in the fresh food ranged from 0.189 to 2.82 ng/g ww. The analysis of the food packaging samples themselves showed that they contained 8.94 – 4120 ng total OPEs/g food packaging material and the same OPE analogues as those detected in the packaged food. According to the authors that “implies that the food-packaging material can be an important contamination source of OPEs in packaged foodstuffs.” In contrast, food additives were excluded from being an important source of OPEs.
The researchers calculated the median daily intake of the 14 analyzed OPEs via food to be 65.4 ng/kg bw for an adult living in China. Cereals contributed the most to the exposure (by 73%). They concluded that “although the health risk of theses traditional OPE analogues is estimated at low levels for the general population in China, attention should also be paid to some novel OPEs in foods in the future.”
Wang et al. were not the first to report packaging as a source of OPEs. TPhP, TCIPP, TCEP, and five other OPEs have been detected in migrates or extracts from food contact materials (FCMs) in more than a dozen studies according to the Food Packaging Forum’s FCCmigex database. All eight of the OPEs were measured in paper and board FCMs, and seven in plastics even though plastics have been studied more than twice as much as paper and board materials. OPEs were never detected migrating from glass or ceramic packaging and only three times in metal FCMs.
Organophosphate pesticides have been previously reported to act as endocrine disruptors, e.g., by reducing semen quality (FPF reported).
Reference
Wang X. et al (2022). “Organophosphate Esters in Foodstuffs from Multiple Provinces in China: Possible Sources during Food Processing and Implications for Human Exposure.” Journal of Agricultural and Food Chemistry. DOI: 10.1021/acs.jafc.2c03603
