Food contaminants cobalt

Different metals and metal compounds have been in use since the beginning of human civilization. Metals include aluminum, antimony, cobalt, copper, chromium, iron, nickel, manganese, molybdenum, selenium, tin, vanadium, and zinc. The list of toxic metals includes but is not limited to arsenic, beryllium, cadmium, hexavalent chromium, lead, and mercury. Contamination of food, water, and the air by metals, particularly lead and cadmium, has caused global concern. Several studies have shown elevated levels of lead, nickel, chromium, and manganese in children s hair. 

People may ingest cobalt-60 with food and water that has been contaminated, or may inhale it in contaminated dust. The major concern posed by cobalt-60, however, is external exposure to its strong gamma rays. This may occur if you are exposed to an orphaned source, or if you come in contact with waste from a nuclear reactor (though this is very unlikely). 

The earlier literature on the effect of metals on rancidity in fats has been well covered by Lea (1939). The accelerating effect of copper and iron on oxidation of fats and fat-containing foods is well established by a wealth of experimental evidence. Other metals, particularly vanadium, cobalt, and manganese, may also be strong pro-oxidants but are less likely to contaminate foods. These metals can accelerate rancidity either in the form of the solid metal in contact with the fat or as water- or fat-soluble salts in heterogenous systems. Aluminum, tin, and zinc have little catalytic activity under most conditions, although tin can act as a surface catalyst for dry fats (Lea, 1946b). 

For irradiation, the ionizing radiation used are gamma rays, generated from the decay of radioisotopes cobalt 60 or cesium 137, X rays, and electrons, the latter two generated by machines for such purposes. The operators of equipment involving ionizing radiation need to be protected from its effects. The ability subsequently to pasteurize or irradiate food should not compensate for best practices to minimize contamination of food before treatment. Moreover, treated food also needs to be protected from subsequent contamination. 

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