The Codex Classification of Foods and Feeds is intended primarily to ensure the use of uniform nomenclature and secondarily to classify foods into groups and/or sub-groups for the purpose of establishing group maximum residue limits for commodities with similar characteristics and residue potential. The major differences in exposure to pesticides and metabolites of pesticides in plants and animals call for a primary classification into foods and feeds of plant origin and those of animal origin. Processed foods prepared from these primary food commodities are again separated into those of plant origin and of animal origin. Multi-ingredient manufactured foods containing ingredients of both plant and animal origin are listed as plant or animal origin depending upon the main ingredients. In the event that residues are greater in the processed food than in the raw agricultural commodity from which it is derived, as a separate MRL should be considered for the processed food. In addition, there are a number of situations where special considerations may be needed: (i) when the processed food represents the sole or major food intake of infants and young children; (ii) when toxic interaction or degradation products from pesticides are found in the food during or after processing; (iii) when a significant residue results from a pesticide used in processing or storage practice (including impregnation of wrapping materials) Crops, parts of crops and other commodities which are used as animal feed, eg alfalfa, sugar beet tops, pea vines and hay, may contain residues and hence give rise to residues in products of animal origin. Such commodities are listed for convenience in a separate class: Class C - Primary Animal Feed Commodities The food commodities selected for this classification are mainly those having current or potential significance in international or national trade. A limited number of commodities of regional importance have also been included.