Hi. A word "food" hasn't got plural form. Are "GMFs" and "Genetically modified foods" correct forms? I saw such forms many times. I guess "foods" means here "products", doesn't it?

Question

Answer

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.

Answer

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.