Food Safety and Zoonoses

Reliable evaluation of low-level contamination of food

Report of a workshop in the framework of GEMS/Food-EURO, Kulmbach, Germany, 26-27 May 1995 - ADDENDUM January 2013


Within the WHO European Programme for Monitoring and Assessment of Dietary Exposure to Potentially Hazardous Substances (GEMS/Food - EURO), measures are undertaken to assure the reliability and comparability of data handled in this Programme.

During the collation of contamination data on various food items and diets, there are always some analytical results which will be reported as non-detectable (ND), i.e. the analytical result is below the limit of detection (LOD), or nonquantifiable (NQ), i.e. the analytical result is below the limit of quantification (LOQ). Such qualitative results must be combined with quantified (numerical) data expressed as numerical, statistical figures such as median and 90th percentile.

The workshop discussed various calculation methods and agreed that the present unsatisfactory situation could be improved by applying easy to use mathematical or graphical extrapolation models which will be made available to GEMS/Food-EURO participating National Contact Points. The recommended procedure ensures the reliability and comparability of GEMS/Food-EURO data sets and results in a more realistic description of the contamination of food; the responsible authorities will be provided with sound information forming the basis of their decisions.


Last update:

12 June 2014 23:09 CEST