A wide range of raw agricultural commodities (RAC) are processed before consumption by the public. In fact, many RACs are consumed in multiple processed forms [e.g. grapes (RAC), raisins, grape juice, wine; potato (RAC), chips, cooked, baked and fried potato, dehydrated flakes]. The processes that are used (industrial or domestic) to produce these foods are diverse and varied. From a consumer protection point of view it is always important to know not only the residues in the RACs but also the residues in the processed commodities, i.e. in the ready-to-eat food. This information is essential for refinement of the dietary exposure. Additionally, it is important to know the residues in processed feeds to calculate the dietary burden for feeding studies and thus to estimate the probable residues in products of animal origin. Studies on the magnitude of residues in processed commodities provide data on the transfer of residues to different processed commodities from the raw agricultural commodity (RAC). Studies on the magnitude of residues are conducted in order to quantify levels of residues in processed commodities and to provide the distribution of residues (active ingredient, and/or metabolites, degradation products) in various processed products resulting from the processing of a commodity.