Survey of the migration of melamine and formaldehyde from melamine food contact articles available on the UK market

Abstract

The migration of melamine and formaldehyde, monomers used in the production of melamine-ware food contact articles, has been determined from 50 retail articles purchased in the UK. The food simulant 3% aqueous acetic acid was used as this is the most aggressive simulant towards melamine plastics. The test conditions used were repeated exposure to the simulant for 2 hours at 70°C, since the articles were all intended for general use including contact with hot foods and beverages. Melamine migrated from 43 of the 50 samples tested and formaldehyde migrated from all 50 samples. Directive 2002/72/EC specifies migration limits for both of these monomers in foods and food simulants. Melamine is restricted by a specific migration limit (SML) of 30 mg/kg (equivalent to 5 mg/dm²) and formaldehyde, along with hexamethylenetetramine expressed as formaldehyde, is restricted by a total (T) SML(T) of 15 mg/kg (equivalent to 2.5 mg/dm²). In all cases the migration of melamine was much lower than the SML for this monomer. The migration of formaldehyde exceeded the SML(T) for 5 of the 50 samples tested. The failure to comply with the SML(T) was accompanied by a number of visible surface effects including discolouration and/or pitting of the simulant contact surface and cracking of the articles. Similar surface effects were observed when one of the samples was exposed to fruit juice which confirmed the suitability of the exposure conditions and 3% acetic acid as a simulant for the articles tested. The ratio of specific migration to overall migration was consistent with, but did not prove, the hypothesis that high formaldehyde migration could be due to the use of excessive hexamethylenetetramine in the polymer formulation. All illegal products were voluntarily removed from the market by the product suppliers.

Keywords:

• Melamine
• formaldehyde
• analysis
• migration
• specific migration limit

Acknowledgments

The authors thank Mrs Betty Borrill at the Procter Department of Food Science, University of Leeds, for supplying the check samples for blind analysis. We gratefully acknowledge financial support from the UK Food Standards Agency (FSA) for funding this work which was part of a survey on chemicals used in plastic materials and articles in contact with food (Food Standards Agency 2004). The statements and conclusions in this paper are the responsibility of the authors alone and they should not be taken to represent the opinion of the Food Standards Agency.