I ate undercooked steak, what can happen to me?

The risks of eating undercooked steak vary based on the the region, the risk status of the person involved (are they a child, elderly, or immunocompromised in any way).

For normal healthy adults, the risks of eating a single bit of under cooked steak in any of the industrialized nations are fairly small.

• Nothing might happen
• You might suffer from food-borne illness, most likely e coli. from steak, with consequences ranging from:
  • You might get a "tummy ache"
  • You might suffer flu-like symptoms or vomiting for a few days
  • You might die, but it is quite unlikely

Note that food borne illness normally takes at least 24-48 hours to develop, and is related to the quantity of contaminated food consumed. One bite is lower risk than a whole meal (lower, not none).

If you are seriously concerned, you should consult your physician.

See also: Foodborne Diseases Factsheet from Texas state government

Exactly how it's been undercooked is also a factor.

If you have an item that's been well-cooked on one side, without being cooked on another side, you're at a much higher chance for pathogens than something that's been well seared but still rare in the middle.

Besides what SAJ14SAJ has mentioned, you want to cook all exposed surfaces. In the case of ground meat (which exotec has mentioned) almost everything is an exposed surface, which makes it much more difficult to deal with, and you're dealing with more complicated machinery that's more difficult to clean than a simple blade.

You then have other factors, such as how it's raised, where it's been processed, how long it's been since it was cut and what temperature it was held at, etc. In general, the less time since it's been cut, the less risky it is, assuming all other things (like the cleanliness of where it was processed) being equal.

All of that being said, eating raw beef on its own is not a problem. There are plenty of places where it's still practiced. My experience has been with Ethiopean food -- kitfo is raw, ground beef with spices, while gored gored is cubed, raw beef. Inuit also eat raw meat, but it's typically frozen first, and rarely beef.

As for what might happen ... that's been pretty well covered on the bad side ... but there are also groups out there who advocate eating raw meat, or even rotting meat to help with digestive issues. I don't know that I'd personally recommend it, though.

There is nothing wrong with eating rare meat, assuming the meat is fresh and was handled and refrigerated properly. I have been eating blue rare meat my whole life, and often eat raw beef in sushi or tartar. There is no need to worry. Rare hamburger, on the other hand, can be risky due to the surface area of the meat and the fact that portions of the meat that are inside the burger will have potentially been exposed to bacteria.

I had eaten a blue rare 6oz steak, cooked very briefly on the grill, both sides, and was having sever diahrreah, abdominal pain, and vomiting for 2 days before it went away. This was also in North Dakota and was cut very fresh and of the highest grade! Let's keep in mind that everyone digests food differently, some better than others (this has a lot to do with blood type and genetics). So if your able to eat blue rare steak or other undercooked meats, do not think everybody else will be able to as well! This is dangerous advice and could get someone seriously ill. Some of the confidence shown in undercooked meat on this thread is very worrisome, as my family in particular has trouble processing undercooked meats, especially low grade. Stay safe and cook it to at least a light pink if your unsure! Better to eat safe than sorry ?

Well, considering that "steak tartare" is raw steak... I'd say you probably don't have too much to worry about! The dangers in raw beef are mostly for ground meat. That's because the facilities processing it may harbor bacteria which can be harmful (read: salmonella, for instance). Those bacteria are typically less harmful in whole cuts, like steak.