Why Does Beef Turn Green? A Full Guide

Have you ever opened your fridge to find that your beef has turned an unusual shade of green?

It can be a bit alarming, but don’t worry – it doesn’t necessarily mean that your meat has gone bad.

In fact, there are a few different reasons why beef can turn green, and it’s important to understand them so that you can determine whether or not your meat is still safe to eat.

In this article, we’ll explore the science behind why beef turns green, and what you should look for to determine whether or not your meat is still fresh.

So let’s dive in and learn more about this fascinating phenomenon!

Why Does Beef Turn Green?

As we mentioned earlier, there are a few different reasons why beef can turn green. One of the main causes is exposure to light and heat. When light hits the meat, it can split into different colors like a rainbow. This is because beef contains various compounds like iron and fat, which can reflect and refract light in different ways.

Additionally, some cuts of beef may have areas of a silver or iridescent color, which can also appear greenish. This is due to the presence of muscle fibers that contain iron-bearing compounds. These compounds help give beef its red color when it’s uncooked, but they can also absorb red hues from refracted light, resulting in a greenish tint.

Another reason why beef can turn green is due to processing techniques. Deli meats, for example, are often cured before they’re sold. This alters their chemical structure and makes them more prone to color changes when exposed to oxygen or light. This is why you may notice that deli-sliced roast beef can sometimes appear green or gray.

The Science Behind Beef Turning Green

When it comes to the science behind beef turning green, there are a few factors at play. One of the main causes is the presence of myofilaments, which are strands of muscle protein that make up the structure of beef. When these myofilaments are cut at the right angle, they can reflect light in a way that creates an iridescent or rainbow appearance on the surface of the meat.

This phenomenon, known as birefringence, occurs because muscle proteins are arranged in a specific way that allows them to reflect light in a particular pattern. When light hits the meat, it splits into different colors and reflects off of the myofilaments, creating the characteristic appearance associated with iridescence.

In addition to birefringence, another factor that can cause beef to turn green is exposure to oxygen or processing techniques like curing. When beef is exposed to oxygen, it can react with compounds in the meat and cause discoloration. This is why you may notice that beef that has been sitting in the fridge for too long can sometimes turn green or gray.

Oxidation: The Culprit Behind Green Meat

One of the main causes of green meat is oxidation. When meat is exposed to oxygen, it can react with the myoglobin protein in the muscle tissue. This reaction can cause the myoglobin to break down into different pigments, such as sulphmyoglobin, choleglobin, verdoheme, nitrihemin, or nitrimyoglobin, which can give the meat a greenish hue.

Atmospheric pressure plasma (APP) treatment is another factor that can contribute to the oxidation of meat. APP treatment can induce green discoloration of myoglobin by promoting nitrimyoglobin formation. Nitrite production in myoglobin solution after APP treatment provides a positive environment for nitrimyoglobin formation. The addition of a reducing agent like sodium dithionite can result in the formation of deoxymyoglobin, which can be converted to nitrosomyoglobin upon APP treatment to yield a desirable red color.

To prevent oxidation and subsequent green discoloration in meat products, plant extracts like acerola cherry extract can be used as natural antioxidants. Acerola extract acts as a reducing agent and improves color stability in raw, uncured and cured meats, and sausage products. It also acts as a cure accelerator in cured meat products, making it an excellent consumer-friendly option for meat manufacturers. When combined with other extracts like rosemary and green tea, acerola can maximize flavor and color retention during long term storage for enhanced protection.

How To Tell If Your Beef Is Safe To Eat

It’s important to know how to tell if your beef is safe to eat, especially if it has turned green. One of the first signs that your beef has gone bad is a foul odor. If your beef smells off or has a cheesy smell, it’s best to throw it out. Additionally, if the use-by-date has passed or the meat is discolored, it’s a clear sign that it’s no longer safe to consume.

Another way to tell if your beef is expired is by checking for a slimy surface film. This film will make the steak appear shinier than usual and will have a slippery or sticky feel when touched. If you see this film on your steak, it’s a sign that it’s starting to spoil and should be thrown away.

If you don’t see any film on your steak but notice an odd color, like brown, yellow, or green, it could also be a sign of spoiled beef. Meat color can change depending on how it’s packaged and how long it’s stored. Freshly sliced beef is purplish in color due to myoglobin, but as soon as myoglobin is exposed to the air, it reacts with oxygen to form bright cherry-red oxymyoglobin. Meat that is vacuum packaged will retain its purplish color, while meat wrapped in plastic wrap that allows oxygen to pass through will retain the cherry-red color. However, continued exposure to oxygen can lead to the formation of metmyoglobin, a pigment that turns beef brownish-red. While color changes are normal for fresh meat stored in the refrigerator or freezer, spoilage beef tends to develop an off-odor, be sticky or tacky to the touch, or even be slimy.

Finally, you can also tell if your ground beef has gone bad by checking for a rancid smell. Fresh ground beef has a barely perceptible scent, but rancid meat has a tangy, putrid odor due to the increased growth of spoilage bacteria. If you notice any signs of spoilage in color or texture but don’t detect a funny scent, it’s still safest to throw it away as pathogenic bacteria cannot be smelled.

Tips For Preventing Beef From Turning Green

To prevent beef from turning green, it’s important to take some precautions when storing and handling it. Here are some helpful tips:

1. Keep beef away from light: As we mentioned earlier, exposure to light can cause beef to turn green. To prevent this, store your beef in a dark place like the back of your fridge or in a covered container. Avoid leaving it out on the counter or in a well-lit area.

2. Store beef properly: Beef should be stored at or below 40°F to slow down bacterial growth and prevent discoloration. Make sure your fridge is set to the right temperature and that your beef is stored in airtight packaging.

3. Use beef quickly: Cook beef as soon as possible after purchasing to prevent bacteria growth and discoloration. If you’re not planning on cooking it right away, freeze it instead.

4. Check for spoilage: While greenish tinges alone don’t necessarily mean that the beef is spoiled, it’s still important to check for other signs of spoilage like a slimy texture, strange smell, or mold spots. If you notice any of these signs, it’s best to throw the beef out.

By following these tips, you can help prevent your beef from turning green and ensure that it stays fresh and safe to eat.

Other Factors That Can Affect The Color Of Your Meat

Aside from the factors mentioned above, there are other factors that can affect the color of your meat. One of these factors is the animal’s diet. The food that an animal eats can have an impact on the color of its meat. For example, if an animal is fed a diet that’s high in beta-carotene, such as carrots or sweet potatoes, its meat may have a slightly yellow or orange tint.

The age of the animal can also impact the color of its meat. Younger animals tend to have lighter-colored meat, while older animals have darker-colored meat. This is because older animals have more myoglobin in their muscles, which gives their meat a darker color.

The way that the meat is stored and handled can also affect its color. If meat is exposed to oxygen for too long, it can start to turn brown or grayish in color. This is because the myoglobin in the meat has oxidized and turned into metmyoglobin, which has a brownish-gray color.

Finally, the cooking method used can also affect the color of your meat. Overcooking your meat can cause it to turn brown or gray in color, while undercooking it can leave it with a pinkish-red hue. It’s important to cook your meat to the appropriate internal temperature to ensure that it’s safe to eat, but also to avoid overcooking it and changing its color.