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If you have ever opened a package of sliced roast beef and noticed red or pinkish-red liquid around the meat, your first thought may have been: “Is that blood?” At first glance, the liquid can certainly look concerning, especially when it collects at the bottom of the package.
The good news is that in most cases, what you are seeing is not blood. The reddish liquid is related to the natural properties of meat and the way it is stored and packaged.
This small detail actually reveals an interesting part of food science. The color of meat is more complicated than it may seem, and the red color can come from a naturally occurring protein in muscle tissue called myoglobin.
Myoglobin helps store oxygen in muscles and is one of the main factors responsible for the characteristic red color of beef. The USDA explains that blood is removed during slaughter, while the small amount of liquid that remains in the meat is primarily natural moisture combined with proteins.
That means when you see red liquid inside the package, you should not automatically assume that the meat is “swimming in blood.”
In fact, beef contains a large amount of water. When meat is chilled, transported, stored or placed in vacuum packaging, some of that natural moisture can gradually leave the tissue. In the food industry, this is often referred to as “purge,” or the release of meat juices.
But why does this liquid look red?
Once again, the answer is related to myoglobin.
When myoglobin is in a certain state and there is little oxygen around it, meat can appear darker red or even purplish. When it is exposed to oxygen, oxymyoglobin forms, giving the meat a brighter red appearance. With longer exposure to oxygen, additional chemical changes occur and the meat can eventually become brownish.
This is why the color of meat can look different depending on whether the package is vacuum-sealed, how long it has been sitting on the shelf and how much oxygen has reached the product.
It is also why some people are surprised when they open vacuum-packed meat. The interior can appear darker or purplish, and after being exposed to air, it may gradually become brighter red.
However, color alone is not enough to determine whether meat is safe to eat.
That is an important distinction.
Many people judge meat simply by its color. But official food-safety recommendations emphasize that a change in color by itself does not necessarily mean that the meat has spoiled. Other signs of spoilage can include an unpleasant odor, an unusually sticky or slimy surface and an abnormal texture.
So, if you open a package of roast beef and notice a small amount of reddish liquid, there is no need to panic simply because of the color.
It is more important to consider the entire product.
What does the meat look like? Does it have an unusual smell? Does the package look damaged or swollen? Has it been stored properly? Has the date on the package passed? Has it remained refrigerated?
These questions are much more useful than simply judging the color of the liquid.
Proper storage is especially important.
The FDA recommends refrigerating perishable foods promptly and keeping the refrigerator at or below 40°F (4°C). Foods that require refrigeration should also not be left at room temperature for more than two hours, or more than one hour when the temperature is very hot.
This rule is much more important for meat safety than whether the juice inside the package looks pink or red.
Another important factor is time.
Ready-to-eat meat products should be consumed within an appropriate period. The FDA notes that with refrigerated ready-to-eat foods, including deli meats, longer storage can increase the opportunity for certain bacteria, including Listeria, to grow, particularly when refrigerator temperatures are too high.