In an article published on November 8, 2016 in the peer-reviewed journal Food Additives & Contaminants: Part A, Veruscka Mannoni and colleagues from the Istituto Superiore di Sanità, Rome, Italy, report on the migration of formaldehyde and melamine from melaware and other amino resin tableware. “Melaware” is a generic term indicating a family of food contact articles made of plastic resin obtained from the reaction between melamine (MA) and formaldehyde (FA). Particularly children’s tableware is often made of this material, because it is inexpensive, almost unbreakable, and flexible in supporting different color and shape designs.
The scientists investigated new articles (72; bought on the Italian market from legally recognized importers, low cost retail shops and open-air markets) as well as already used articles (18; obtained from consumers). Migration from select articles was further remeasured after artificial aging. Investigated articles included plates, soup plates, cups, glasses, bowls, and containers, most intended for use by children but some also by adults. Migration tests were performed in 3% acetic acid for two hours at 70°C, selected as the most aggressive (“worst case”) condition, repeated up to three times with a fresh simulant (repeat contact test).
Among the new products tested, the Specific Migration Limit (SML; set by the Commission Regulation (EU) No 10/2011) was exceeded in more than 20% for either FA (SML 15 mg/kg) or MA (SML 2.5 mg/kg), but never for both in one product. In some cases, even the Overall Migration Limit (OML; 60 mg/kg) was exceeded. Migration behavior across the first, second, and third contact tests differed for different products, with migration increasing, decreasing, or remaining constant.
Select plastic articles were further characterized by Fourier Transformed – Infrared analysis, which highlighted the presence of different amino resins based on formaldehyde-melamine, urea-formaldehyde or melamine-urea-formaldehyde, all exhibiting different migration behavior. These results demonstrate that the market-present tableware labeled as “Melaware” in fact consists of different resins with inhomogeneous composition. This complicates the prediction of migration behavior and assurance of compliance.
Among the consumer-supplied used products, despite them being in use for many months already, migration of the FA and/or MA was still measurable in >60% of the products, and the SML of MA was exceeded in one product, with MA migration at 3.4 mg/kg food simulant. The data obtained on real-life samples suggested that, during the prolonged use, not only decreased and constant migration are possible, but migration can even increase due to gradual degradation of the polymer.
Ten of the new products were further subjected to an artificial aging test, simulating up to 18 dish-washer washing cycles, corresponding to a real-life frequent use of 15-30 days. At the 18th cycle the SML of MA was exceeded in 78% of the samples. Interestingly, while some of the products displayed visible deterioration signs, accompanied by increased migration, others had no visible deterioration signs, with gloss and integrity unaffected, but still displayed increased MA migration, even exceeding the SML. These results demonstrate that a good external appearance of aged objects cannot be taken as an indication of low migration. This situation constitutes a significant risk to consumers “since the articles not showing early signs of degradation do not alert the consumer and their use could continue for a long period.”
The authors emphasize that “the monitoring of the market plays a fundamental role for food safety,” because the consumer is not able to distinguish the items of better quality what concerns the migration values. The authors further suggest that melaware articles should be accompanied by an extensive labelling providing detailed information on use restrictions, such as avoiding microwaving or heating directly in the plates, avoiding use with acidic foods or drinks, and quick disposing of items displaying signs of deterioration.
Mannoni, V., et al. (2016). “Migration of formaldehyde and melamine from melaware and other amino resin tableware in real life service.” Food Additives & Contaminants: Part A (published November 8, 2016).