In the past, the practices organic farmers had to follow to label their food organic were regulated haphazardly by a wide variety of state and private certification programs. The standards set by these certification programs were far from uniform. To correct this problem, the Congress of the United States passed the Organic Foods Production Act in 1990. The act mandates the United States Department of Agriculture (USDA) to establish national standards governing the methods used to grow, process, and market organic agricultural products. After a decade of debate, in 2000 the USDA established new regulations that organic farmers and food processors must follow in order for products to be labeled organic. These regulations prohibit the use of genetically modified ingredients, irradiation to decontaminate products, and sewage sludge as fertilizers for any food sold as an organic product. Products labeled “100 percent organic” must contain only organic ingredients, while those labeled “organic” must contain at least 95 percent organic ingredients. Processed food containing at least 70 percent organic ingredients can be labeled “Made with organic ingredients,” and as many as three of the organic ingredients can be listed on the product’s packaging. Only products made from at least 95 percent organic ingredients can carry the USDA organic seal on their packaging and in advertisements.