The following is an edited excerpt.

Unapproved genetically engineered wheat has been discovered in an Oregon field, a potential threat to trade with countries that have concerns about genetically modified foods.

The Agriculture Department said Wednesday that the genetically engineered wheat is safe to eat and there is no evidence that modified wheat entered the marketplace. But the department is investigating how it ended up in the field, whether there was any criminal wrongdoing and whether its growth is widespread.