Following the production of the first transgenic plants, health issues concerning the safety of using genetically modified (GM) crops in foods and feeds have been discussed, debated, and evaluated. The main concerns regarding GM foods include toxin or allergen production, changes in nutrient levels, and development of antibiotic resistance. The U.S. Food and Drug Administration established extensive guidelines to address the concerns and ensure the safe commercial introduction of GM crops for use in food or feed. The guidelines were developed through evaluation of scientific data from several disciplines related to genetic engineering and food safety, and consultation with experts from around the world. Foods containing GM crops meeting the FDA guidelines are deemed to be as safe and nutritious as their non-GM counterparts already on the market.