Student or Learner
The Food goes bad or goes rotten.
The Milk turns sour.
The escalator was out of service.
The traffic light is not functioning.
How we say for tap (The faucet is leaking excessive) and electric toy car (It is not working).
Faucets are not supposed to leak at all. So, "the faucet leaks" or "is leaking" is sufficient.
The electric toy car "doesn't work" or "is not working is fine".
For your first, I would say the food "goes bad" or "spoils".
Pope of the Dictionary.com Forum