<P> Genetically modified foods or GM foods, also known as genetically engineered foods, bioengineered foods, genetically modified organisms, or GMOs, are foods produced from organisms that have had changes introduced into their DNA using the methods of genetic engineering . Genetic engineering techniques allow for the introduction of new traits as well as greater control over traits than previous methods such as selective breeding and mutation breeding . </P> <P> Commercial sale of genetically modified foods began in 1994, when Calgene first marketed its unsuccessful Flavr Savr delayed - ripening tomato . Most food modifications have primarily focused on cash crops in high demand by farmers such as soybean, corn, canola, and cotton . Genetically modified crops have been engineered for resistance to pathogens and herbicides and for better nutrient profiles . GM livestock have been developed, although as of November 2013 none were on the market . </P> <P> There is a scientific consensus that currently available food derived from GM crops poses no greater risk to human health than conventional food, but that each GM food needs to be tested on a case - by - case basis before introduction . Nonetheless, members of the public are much less likely than scientists to perceive GM foods as safe . The legal and regulatory status of GM foods varies by country, with some nations banning or restricting them, and others permitting them with widely differing degrees of regulation . </P>

When were genetically modified crops first introduced for commercial production in the u.s