Basically there is no right or wrong advice here, mainly because most people don't know, and have never learned to trust their senses. Long story short: After cooking or flavoring there is no halfway reliable way determining 'rotten' foodstuff.
Long story long:
We're the product of billions of years of evolution. Two centuries ago nobody knew about bacteria, microbes, their toxins and what really happens when food gets spoiled, no freshness dates and so on. But we wouldn't have lasted a decade without sensing spoiled food before eating a stack of rotten meat. So YES, we CAN detect rotten foodstuff. It's just not easy, involves quite a bit of trial and error, and overall depends on your cleverness not to eat something that tastes bad.
Let me give you an example: The botulinum toxin is produced by different specimen of clostridium botulinum. It is one of the most toxic substances mother nature is able to throw at us, and it's undetectable by any sense (unless it's too late).
BUT: One must be a quite stupid fellow to get lethally intoxicated (by spoiled food, that is - not counting the Botox faces). So why is it that hard to die of this poison? Clostridium is a bacteria that loves meat (as almost all microorganisms do), but it hates oxygen. It won't grow colonies on the finest meat if exposed to air. To maintain the metabolism it can't just produce the quite complicated toxin, it has to digest something, like proteins, fat or sugar. During this digestion it produces massive amounts of substances we can detect, like butyric acid, acetic acid, acetone and other fine stuff nobody sane would eat. In fact most people will instantly feel a strong urge to gag or even puke if presented with the acid-sweet smell of botox meat in the morning. [ed. Please refer to the comments. I suggest the struck-out text is dangerous if understood to be the whole truth.]
The same is with almost all other food poisoning stuff - if your fish smells like it has had a quite long sunbath, it most probably isn't save to eat any longer. If your chicken feels like somebody oiled it with egg white, it has had some quite similar treatment by some small guys you dead sure don't like to eat.
So eat and drink as you fancy, but don't eat stuff that tastes awkward (and isn't supposed to do so - some people like funny tastes, and some tastes you have to get used to). Of course it will lead to wasting some food that still is good and proper, but it keeps you safe for a quite long time. It worked the last few billion years for a massive amount of species, why should it stop working now?
And, as others pointed out before: Microbes are no problem. LOADS of the wrong type present one. Some people can eat quite rotten stuff without any problems, for 1st-world citizens this won't work that good. You have to get used to the microbes you eat, and you will get a higher tolerance threshold for most toxins and microbes when eating/drinking mostly 'infected' foodstuff. That's why the average Indian can eat the ice cream on the market by the ton, while it will give you quite some friendship time with Mr. Toilette if just eating a small one.
By the way: Always being on the safe side is not that good either, because if you find yourself in front of the wrong plate one day, you will have the time of your life. Or not. Our immune system (and everything connected to it, like your gastro-intestinal system) is like a muscle - if you don't train it, it will always be weak and thus break down on every occasion. And most food poisoning problems (like salmonella) are breakdowns of your immune system and/or your gastro-intestinal flora.