According to Buzzfeed, it turns out that the substance in question is not blood at all, but rather a protein called myoglobin. The protein is responsible for the red color of the meat and its fluids, and it is completely usual to find it in food packaging.
What is the red liquid in steak juice?
Aspects of ″Red Juice″ that you should know about: myoglobin in your steak That bright crimson liquid you’re looking at is simply a mixture of water and a protein known as myoglobin. As a result of being exposed to oxygen, the iron contained inside this protein becomes red in color. This mechanism is remarkably similar to the one that hemoglobin does in the human body.
Why does steak turn red when cooked?
After everything is said and done, the ″blood″ in your steak isn’t actually blood at all. It’s myoglobin, the protein responsible for delivering oxygen to the muscles of an animal. When flesh is chopped or exposed to the air, this protein becomes red in color. The protein darkens in color as a result of being heated.