Survey of counterfeit melamine tableware available on the market in Thailand, and its migration

A simple measurement of sample density by adopting the principles of buoyancy could help screen counterfeit melamine ware if the density was below 1.50 g cm-3. However, samples with a density exceeding 1.50 g cm-3 were not necessarily made from melamine formaldehyde. FTIR analysis showed that all counterfeit products were made of urea formaldehyde and coated on the food-contact side with melamine formaldehyde, a tactic probably intended to cover up the true product features. The overall migration of real and counterfeit melamine samples complied with both European Union and Thai regulations, as the exposure layers in both cases were melamine formaldehyde. Formaldehyde migration failed to comply with Thai standards, but this was not the case for European Union standards. However, the results showed a significant inconsistency between individual items of the same brand and between individual exposures of the same test specimen. This indicated the inherent inhomogeneity between individual items, which mainly resulted from the manufacturing process: for instance, insufficient temperature and time to obtain complete polycondensation of monomers. Therefore, it is recommended that constant surveillance be conducted on melamine articles available in the marketplace in terms of quality and safety.