I make vegetable juice using a mixture of carrots and tomatoes that I cook in boiling water. I just transfer them to a refrigerator once they’ve cooled and use them accordingly. I recently haven’t been able to eat that for a while (maybe a week?) and noticed that the water became very gooey and the tomatoes started smelling a bit sour. It seems okay to eat (I was fine today after eating it this morning) but I’m wondering why that happens and whether it’s safe to eat or not. Thanks.
Sounds like they indeed started to ferment. Those are the sour and probably slightly funky flavors your getting…But unlike intentional fermentation where you use something like salt to inhibit bad bacterial growth yours are just creating bacteria of all kinds. Throw it away.
If you ever want to try to ferment those in a safer way add 2-3% salt to them by weight.
I don’t know too much about fermented tomatoes. I would only give cooked fruits/veggies foods no more than 5 days in the refrigerator. Some people may say less time than that. You may be growing dangerous bacteria or mold. Basically, if it’s unappetizing after a few days, throw it out.