...The use of carbon monoxide deceives consumers and creates an unnecessary risk of food poisoning by enabling meat and ground beef to remain fresh-looking beyond the point at which typical color changes would indicate ageing or bacterial spoilage, according to Kalsec, Inc. of Kalamazoo, Michigan, a privately-held supplier of natural spice, herb, hop, and vegetable extracts for use in food, beverage, and pharmaceutical applications.
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Moreover, the petition claims the FDA did not have legal authority to permit the use of carbon monoxide in fresh meat packaging because it is an unapproved and prohibited color additive, and the agency bypassed the required procedure for carbon monoxide to obtain a color additive designation, a necessary precondition for making it legal to use carbon monoxide in fresh meat packaging, according to the petitioners.
Regulations of the U.S. Department of Agriculture's Food Safety and Inspection Service (FSIS) prohibit the introduction of ingredients in fresh meat that function to conceal damage or inferiority, or give the appearance the product is of better or greater value.
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The use of carbon monoxide has been banned in other countries. In 2003, the European Union prohibited the use of carbon monoxide in meat and tuna.
http://www.consumeraffairs.com/news04/2006/02/fda_meat.html