Q.Fertilizer/ compost
I have kept unopened sealed bags of vegetables & salad leaves bought from stores but not used by the expiry dates and past their best for eating. They have been kept unopened in an outdoor shed for some months. Over time the contents of these still unopened bags has decomposed & fermented inside the bags so the bags now contain just liquid not solid matter.
Can this liquid be used as fertilizer?
You should compost the food scraps before using for fertilizer.
Here is an article with more information.
https://www.gardeningknowhow.com/composting/ingredients/composting-kitchen-scraps.htm