In the United States people will talk about “genetically modified foods” but they will refer to these as “GMOs” (Genetically Modified Organisms) As for the word “food”, this was covered well I the other post.

Food is a variable noun. In some situations, it is uncountable, and in others it is countable. I recommend the online Collins dictionary for English learners. It states when a noun is variable and gives examples. link: https://www.collinsdictionary.com/dictionary/english/food excerpt food VARIABLE NOUN Food is what people and animals eat. examples Enjoy your food. ...supplies of food and water. ...emergency food aid. ...frozen foods.