Myth: The Liquid at the Bottom of a Meat Package is Blood
The liquid which can sometimes be found at the bottom of a meat package is what meat scientists call “purge,” is a combination of water and meat proteins that drain from meat. One of those proteins, water-soluble myoglobin, is the key reason for the meat’s red color, which is why the water is also red or dark pink.
Meat is typically 75 percent water, which contributes to the juiciness of cooked meats. The proteins in a steak are like a sponge that holds the water. As meat ages and is handled or cut, proteins lose their ability to hold onto water. Over time, some water is released and myoglobin flows out with it, giving the liquid a red or pink color.
The liquid in a package is similar to what you find when you cook a steak. Cooking changes the purge a bit as water evaporates from meat when it’s cooked. That’s why your cooked steak or burger is smaller than when you first put it on the grill. Myoglobin also changes color during cooking. That’s why a rare steak will have red juices which a well done steak’s juices are clearer, though it is important to remember the true test of doneness is checked with a thermometer.
There are a variety of factors related to how well meat holds on to water which can include the species and age of the animal, the fatness and grade of the meat, the length of time since the animal was harvested, which muscle the cut of meat was from, and how the meat has been handled and processed. The liquid’s color is primarily determined by the age of the animal when it is harvested. Animals harvested at a younger age such as pigs or veal calves have less myoglobin in their muscles than older animals, hence a pinker liquid color for pork or veal and a darker red for a steak.
Liquid in a meat package should be handled carefully just like the meat itself. Purge in a meat container can carry the same bacteria as a raw piece of meat so it should be handled with care. Wash your hands after touching meat or “purge”, don’t consume it unless it has been cooked to a proper temperature, and try to contain it carefully to prevent cross contamination.