In an article published on May 15, 2020, in the peer-reviewed Journal of Hazardous Materials, Jazmin Osorio and colleagues from the Analytical Chemistry Department, University of Zaragoza, Spain, and the ASSET Technology Centre, Queen’s University Belfast, Northern Ireland, UK, reported on the analysis of substances migrating from a “bamboo-based biopolymer packaging.” The test samples were “cups, dishes and jugs” bought at a local supermarket. The authors explained that the tested materials “cannot be considered as bamboo, but [as] melamine [plastic] with bamboo filler,” and thus are subject to safety requirements and testing procedures outlined in the regulation (EU) 10/2011 for plastic food contact materials (FCMs). Therefore, migration was carried out according to standard procedures for testing plastic food contact materials (FCMs) in the EU, using ethanol 10% (v/v), acetic acid 3% (w/v) and ethanol 95% (v/v) as simulants for aqueous, acidic, and fatty foods, respectively. Gas chromatography-mass spectrometry (GC-MS) was used to analyze volatile and semi-volatile migrants, while non-volatile migrants were analyzed by ultra-performance liquid chromatography coupled to time-of-flight mass spectrometry (UPLC-Q/ToF).
The authors reported migration of 25 volatile and semi-volatile compounds, of which four compounds are assigned to Cramer class III (i.e., high toxicity: methyl N-hydroxybenzencarboximidate (no CAS); 3β-ergost-5-en-3-ol, CAS 4651-51-8; clionasterol, CAS 83-47-6; arundoin, CAS 4555-56-0) and one compound to Cramer class II (i.e., medium toxicity: stigmasterol, CAS 83-48-7), while the rest are assigned to Cramer class I (i.e., low toxicity). The phytosterols were detected only in ethanol 95% food simulant. Since they have been previously detected in young bamboo shoots, they could originate from the bamboo used in the tested articles. Phytosterols were shown to not exhibit genotoxicity and some studies have even reported some beneficial effects resulting from phytosterol intake. Non-volatile migrants included 12 compounds, including melamine (CAS 108-78-1) and eight of its derivatives, as well as a surfactant triethanolamine (CAS 102-71-6), an amino acid valine (CAS 72-18-4) thought to originate from bamboo, and one unknown compound with a molecular formula C2N4O3S2. Migration of melamine and its derivatives was detected in all three food simulants and migration at levels exceeding melamine’s specific migration limit (i.e., 2.5 mg/kg) was observed in several cases. In 2019, melamine has been reevaluated by International Agency for Cancer Research and classified as being “possibly carcinogenic to humans” (FPF reported). In November 2019, melamine was also included on the Substitute It Now (SIN) list (FPF reported) and highlighted as an important substance of concern due to its persistent, mobile, and toxic (PMT) properties (FPF reported).
The authors concluded that “the addition of the polymeric [melamine] resin to the bamboo biopolymer improved its mechanical properties but at the same time, entailed a risk to consumer’s health. In addition, melamine is neither a biopolymer nor biodegradable, what means that these materials, promoted as ‘bamboo food contact materials’ can be considered as a fraud to consumers.” Of note, communication by European Commission published in August 2020 (i.e., already after the publication of this manuscript) has determined that bamboo-based additives are currently not authorized for use in plastic FCMs in the EU (FPF reported), therefore their presence alone would already render the biopolymers tested here non-compliant.
Reference
Osorio, J., et al. (2020). “Ambient mass spectrometry as a tool for a rapid and simultaneous determination of migrants coming from a bamboo-based biopolymer packaging.” Journal of Hazardous Materials 398: 122891.
