If you've eaten spoiled food and it was spoiled enough to make you sick and give you food poisoning you will usually begin feeling sick within a few hours to 4 hours after eating the spoiled meat.
However sometimes it may take as long as 24 hours to start feeling sick after eating the spoiled food.
Most cases of food poisoning are not very serious and usually resolves on it's own within a few days to a week but if you think it's getting worse or not going away then going to urgent care of the emergency room would be a good idea just to make sure you didn't get a more serious form of food poisoning such as botulism which can be deadly.
The symptoms of food poisoning will feel like the stomach flu so if you feel something like the stomach flu then you've likely got food poisoning from the spoiled food.
If the food and meat is spoiled you should really throw it out and not risk getting sick over it.