Wheat (Triticum aestivum L.) is the most important crop worldwide, followed by coarse grains and rice. It is the basic food of eighty percent of the world population. Wheat crop covers the largest area in the world agricultural production. However, wheat may contain certain hazardous elements such as lead, cadmium, arsenic and mercury. Agricultural products like wheat are prone to be contaminated with toxic elements from fertilizer, contaminated agricultural soil and water. Many countries set food safety regulations limiting the amount of toxic elements in agricultural products. The APMP-APLAC Joint Proficiency Testing (PT) (APLAC PT T100) of toxic elements (lead and cadmium) in wheat flour was conducted in 2015-2016. Wheat also contains a number of elements classified as nutrients. The elements such as copper, zinc, iron, nickel and manganese are essential for our biological functions, but high concentrations of such elements are hazardous to our health. With increasing international trade of food and agricultural products, traceable measurements of elements in agricultural products have become one of the essential requirements for ensuring human health.

Reference values provided by KRISS for iron and zinc in the test sample were used as the assigned values for evaluating measurement results of participants. The relevant Calibration and Measurement Capabilities (CMCs) of KRISS are registered in the Key Comparison Data Base (KCDB) of the Comité International des Poids et Mesures (CIPM, International Committee for Weights and Measures) Mutual Recognition Arrangement (MRA).