Laura asks via email:
"Hey food geek, I have a question that I can't seem to find a definite answer to by Googling. Is "pink" chicken always "bad" chicken? I'm currently making Anthony Bourdain's Poulet Roti. It takes a moment to mock those who fear pink in their chicken thighs. My mother strongly disagrees and insists chicken should have no pink whatsoever. On the other hand, she admits fully that her chicken is always--ALWAYS--severely overcooked. So I went to Google, but even it seems to be failing me. I'm finding a bunch of terrible answers on places like Ask!Yahoo where people are using apocryphal examples, or even just personal experience (ie "well, I ate pink chicken 48 hours ago and I'm not sick yet so obviously it's fine"). On the other side of the argument, there's this, and I have no idea how reliable the source is for that, either. Do you know a solid answer? We argue every time I make chicken and I end up giving in for fear of killing everyone (not because they'd be dead so much as because I don't want to hear "I told you so" for the rest of my afterlife), but then, of course, my chicken always turns out--you guessed it--dryer than a desert."
There are a couple of issues here, but I am going to start with the explicit one. The reason that we cook chicken so that it doesn't have pink is because the molecule that makes it look pink, myoglobin, denatures at just around 140°F. If you hold chicken at 140°F for around 7 minutes, then you know you've killed off any bacteria that are in it. Or you can cook it to 170°F, which will do the same. Either way, that should be enough to turn the myoglobin from pink to brown when it denatures.
These temperatures are the same for all bacteria and myoglobin for all meat products, so you may be wondering what makes chicken so special that it needs to get all the pink out, when something like beef is fine with plenty of pink in it. Well, unlike beef and many other types of meat, chicken and other poultry is packed with its skin on, and the skin is where all the bacteria comes from. It's rare to have dangerous bacteria in the meat of an animal, because if it were, the animal would have suffered from the effects of that bacteria. That is, after all, what the immune system is for.
Another reason chickens require more cooking is because chickens have less acidic meat than other animals. Acid, like low temperatures, salt, and higher concentrations of sugar, help inhibit bacterial growth. If you have enough of those factors together, then bacteria will either grow slowly or die out altogether.
Which doesn't mean that chicken that is pink will make you sick. What it does mean is that you can't be sure that it won't make you sick. If the chicken were exposed to salmonella, and the salmonella had enough time to make it deep into the chicken muscle near the bone, then a pink chicken is a dangerous chicken. If the chicken were well tended in life and after, and packaged well, perhaps even brined, then you would be less likely to have a problem. Those of you thinking that a Kosher chicken sounds like it's following all of those rules, you would be correct. Regardless of whatever else it is, Kosher food is very much about keeping people from getting sick from their food.
If a meat is cooked very slowly, then it is possible for the myoglobin to remain in-tact and red, which is one of the situations in which a pink chicken should be safe. If you did cook it very slowly, but you know that it reached a temperature that will kill bacteria for the proper amount of time, then all will be well. Likewise, if you used a proper amounts and combinations of acid, salt, and/or sugar, then you should not have to cook it as thoroughly. In that case, you're likely to be making some sort or charcuterie, and you will need to be careful to follow all of the advice for making it.
To sum up: pink in chicken doesn't equal illness necessarily, but you are increasing your chances, and there aren't a lot of good ways to know what the outcome will be until it's too late. There are plenty of ways of cooking a chicken thoroughly without making it dry and tasteless. My favorite methods are brining or just cooking the dark meat (which tastes better in any case).