Delegate Vani Hari holds signs that say 'Label GMOs' during day two of the Democratic National Convention at Time Warner Cable Arena on September 5, 2012 in Charlotte, North Carolina.

U.S. consumers will see labels on food products that contain genetically modified ingredients as early as 2020, federal officials said Thursday.

The USDA on Thursday released the first national disclosure requirements for foods that have been altered in a way that doesn't occur naturally.

The fight over whether or not to label foods with genetically modified ingredients, also called genetically engineered foods and GMOs, has raged for years. Advocates say consumers should know how their food is made, and opponents worry consumers will interpret labels on bioengineered foods as a warning on foods many agree are safe.

The guidelines, which use the term "bioengineered" instead of the more commonly used "genetically modified," allow disclosure of bioengineered ingredients in several formats: in text, a symbol, a digital link printed on packaging or text message.

Companies can use a QR code with a statement like: "Scan here for more food information." After scanning the code, consumers will be brought to a website where genetically modified foods will be disclosed. If a company provides a digital link disclosure, it must also provide a telephone number consumers can call for information. Critics say companies that use the QR code should be required to include the word "bioengineered" in their statement.