The darkening is due to oxidation, the chemical changes in myoglobin due to the oxygen content. This is a normal change during refrigerator storage.
Browning is the process of partially cooking the surface of meat to help remove excessive fat and to give the meat a brown color crust and flavor through various browning reactions. Ground meat will frequently be browned prior to adding other ingredients and completing the cooking process.
Spoiled meat will have a distinct, pungent smell that will make your face scrunch up. Texture — In addition to an unpleasant scent, spoiled meats can be sticky or slimy to the touch.
Color — Rotten meats will also undergo a slight change in color. Poultry should be anywhere from a bluish-white to yellow in color. Fresh, raw ground beef should be red due to its levels of oxymyoglobin — a pigment formed when a protein called myoglobin reacts with oxygen 3. Beef can sometimes develop a brown color due to metmyoglobin, a chemical reaction that occurs when the myoglobin in meat is exposed to oxygen.
Eventually, the muscle loses the ability to reduce the oxidized myoglobin and the brown becomes permanent. Lots of factors contribute to how fast this oxidation reaction happens. Meat that has been in storage longer will have less ability to reduce the myoglobin. Frozen meat is more prone to oxidizing. Salts and marinades can oxidize the meat cuts and create the brown color. Other situations with very low oxygen can create brown spots.
In some cases, bacteria can cause the meat to turn brown, but when this happens, the bacteria will also create a smell. So, the next time you find some discolored meat in the fridge, give it a sniff.
The Truth Behind Curing Meats. Meat Matters: Is Bigger Better? In order for meat to maintain that bright red color we are familiar with, oxygen must be available at a sufficient concentration.
That is why grocery stores utilize a small film over their products versus a vacuum package. Browning of meat can also occur with meat that has been chilled for a long period of time about 5 days , ie: taken home from the grocery store and placed in your fridge for some time.
Browning of meat can also occur when oxygen partial pressure is low or basically when meat is stacked on top of one another. This is more than likely the case from the photo above. This is also the reason why your ground beef from the store may be red on the outside but brown on the inside. The changing from red to brown and even the purplish color to red occurs quite easily in meat, the reverse is much difficult.
Once meat has browned, it is hard to get it enough oxygen to reverse the process. Also, this same process is the reason meat does indeed turn brown when you cook it. But once meat is cooked, it denatures the proteins so there is really no going back! All of the protein is not affected at the same time which is why you get different variations of a reddish color at different temperature points.
Basically this is what gives us rare, medium rare, medium, well done, etc. Those colors associated with meat temperatures are basically denatured metmyoglobin!
One myth I see commonly brought up is that old meat is dyed red. This is not anything any of us in the meat industry have heard of nor have we found information to supply this so-called practice. The number one indicator of spoiled meat is in fact smell. An off odor will be prevalent to your senses and the most effective way to diagnose spoiled meat.
Another indicator of spoiled meat is tacky or sticky to the touch. Slimy meat not juicy is also a great indicator of spoilage. This especially occurs if meat has been temperature abused. Raw meat that has been heated up not cooked and then re-cooled will often times become sticky or tacky along with possibly a color change. Use these three factors in diagnosing spoiled meat: does it smell, is it sticky, AND does it have color change?
If it is not spoiled, feel free to indulge without worry! Meat Color from University of Saskatchewan. GREAT blog post! I hope a lot of folks read it. One thing with that though is you need to know what should smell like generally. Thanks Janice! I am surprised by the number of people who either bring us meat or call us to ask about meat being spoiled. I, too, hope this post sheds some light on that!
And you are right that smell and touch are relative, but they are the number one indicators we use to diagnose. It amazing to me the. What is looking bad, in this case actually is better. What does the color of ground poultry indicate? Does a change in color indicate spoilage?
How long can you freeze ground beef? What color is normal for livers? Trending Articles How long is meat or poultry safe to use after the sell-by date? How long can you store eggs in the refrigerator? How long can meat and poultry remain in the refrigerator, once thawed?
0コメント