Effects of processing of heavy metal content of foods

Metals occur in all foodstuffs. Of particular concern is the presence of toxic metals, which include lead, cadmium, arsenic and mercury. The toxic metal content of foods is influenced by many factors ranging from environmental conditions during growth to post-harvest handling, processing, preparation and cooking techniques. For example, metal content increases in some commodities grown in contaminated soils or atmospheres while post-harvest handling steps such as washing generally remove metal contaminants. Cooking may reduce metal content although some foods can absorb metals if the cooking water is contaminated. Metals used in food processing equipment or food packaging material may contribute to food contamination. Contamination may also occur during kitchen preparation and storage. This paper will review the effects of processing of foods on toxic metal content. A broad interpretation of processing, to include aspects of food production from growth through cooking, will be taken in discussing the toxic metal content of foods. Specific examples of changes in metal content due to processing will be discussed.