The international experts gathered by WHO have not set a "safe" level of melamine but they have established a "tolerable" level. Melamine is a contaminant that should not be in food however sometimes it is unavoidable. TDI represents the tolerable amount of unavoidable contaminant in food that a person can ingest on a daily basis without appreciable health risk. The TDI is meant to help national authorities set safe limits in food for withdrawal purposes should melamine be detected as a result of intentional adulteration.

The TDI for melamine has been established at 0.2 mg/kg body weight. Based on this, it leads a 50 kg person to a tolerable amount of 10 mg melamine per day. 

The TDI applies to melamine alone. The TDI for cyanuric acid alone remains at 1.5 mg/kg body weight. Co-occurrence of melamine with cyanuric acid seems to be more toxic, however data are not adequate to allow the calculation of a health-based guidance value for this co-exposure.

"At the same time the limits for melamine in infant formula (1 part per million or ppm) and in other foods (2.5 ppm) introduced by many countries provide a sufficient margin of safety as compared to the TDI," added Dr. Schlundt.

The WHO Expert Meeting to review toxicological aspects of melamine and cyanuric acid was held in Ottawa, Canada, 1-4 December 2008. Twenty-one experts attended this meeting.

The executive summary of the meeting will be made available on the WHO Food Safety web page on the melamine contamination event:

http://www.who.int/foodsafety/fs_management/infosan_events/en/index1.html