But interestingly meat can quickly turn brown in minutes when it is vacuum packed. Vacuum packers have become very popular recently. Vacuum sealers help preserve foods by taking out the oxygen thereby prevent oxidation from occurring. Meat is red when the pigment myoglobin that is contained in blood is bound to oxygen. Myoglobin is related to hemoglobin, which is the iron- and oxygen-binding protein in blood, specifically in the red blood cells.
When oxygen is released from myoglobin there is a change in spectral properties of the myoglobin molecule. The result is a brownish color.
The images above show two pieces of grass fed meat that were unprocessed. One was left exposed to the air and the other was vacuumed packed prior to cooking using the sous vide method. The strong vacuum pulled out air and drew oxygen molecules off the surface of the meat.
Removing the meat from the bag showed that only the surface level turned brown. Carbon monoxide binds hemoglobin in much the same way that oxygen does, only x stronger. In fact CO will displace oxygen from hemoglobin or myoglobin because it has such great affinity for hemoglobin. It is a known fact that carbon monoxide is used in processed meats to keep the meat red for long periods of time. Shown below it is interesting that under vacuum the meat remained red.
While carbon monoxide treated meat may not be harmful when fresh it can mislead the consumer who may not be able to smell the actual protein,. Adding carbon monoxide to meat will not only keep meat red while on the shelf but after it's spoiled.
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. If the face cut of the N. I give the costumers a 3X5 instruction card telling them how to prepared it.
I think it is more then 2 years since a costumer came back telling me that steak was not too good. I looked him strait in the eye and told him. Moregarlic aol. Angelo- I miss you and your no-BS attitude!! I hope that my contributions hopefully and at least educate one person out there, if not many! I have missed seeing you at the convention in Davis last month. I printed two copies, I keep one in Petaluma and one in Sonoma deli. He, finally cave in. He took one home, he did as I told him, He is one of the best costumer.
Great post Jenny! Thanks David! And thank you in advance for the traffic! Great blog post, this is the kind of good information we need to get out to consumers every day to help promote good education about meat products. This is awesome! So glad you shed light on this! Thanks Jenny! Being a beef producers daughter I always knew that it was ok, but never knew the science behind it. Thanks for sharing! Thanks for the info Jenny!
Thanks for the info, Jenny. This will help me know when that might be a bad purchase. Thanks Daren! But yes, sometimes there is a fine line.
Smell has been my number one indicator of spoiled meat! Damn you, damn you! Giving away this ranchers secret way of getting inexpensive meat! As a rancher yes we have our own beef but I also buy beef at two local grocery stores fairly regularly. More than once my urban friends are aghast at seeing me buying beef from the store. Two reasons I do, if you watch specials and buy cuts that have lost their color you can save HUGE on beef. Beef just as wholesome, nutritious and delicious as that I would raise and at a cost LOWER than what I could produce the individual cut for.
I really liked how you explained the science behind this. Hopefully this information will help a family that because of budget restraints might enjoy a great beef meal they otherwise would pass up!
Thanks for the great comment Larry! I agree! I would hope that this will either a. Massively helpful for an ignorant cook like me! Raw ground beef should be bright red on the outside and brownish on the inside. If its surface has turned thoroughly brown or gray or grown mold, it has gone bad and should be discarded.
Fresh ground beef should have a relatively firm consistency that breaks apart when you squeeze it. However, a sticky or slimy texture — either when cooked or raw — may indicate the presence of spoilage bacteria. You should toss it immediately To avoid spreading bacteria from one surface to another, wash your hands thoroughly after touching raw meat. If your ground beef has a sticky or slimy texture when raw or cooked, it has most likely gone bad. This test is probably the easiest and fastest way to determine whether meat has spoiled.
It applies to both raw and cooked ground beef. Though the scent of fresh ground beef is barely perceptible, rancid meat has a tangy, putrid odor. The scent changes due to the increased growth of spoilage bacteria, such as Lactobacillus spp. Sell-by and expiration dates are additional guidelines for determining whether your ground beef is good 7. A sell-by date tells the retailer how long a product can be displayed for sale. Ground beef can be refrigerated and safely eaten up to 2 days past this date 3 , 6.
Food will have the best taste and quality before this date. Be sure to carefully read the product label when buying ground beef. Sell-by and expiration dates tell you the best time to eat ground beef. Freezing can further extend its shelf life. Spoiled ground beef is dangerous to eat because it may contain pathogenic bacteria, which are responsible for foodborne illnesses.
Symptoms include fever, vomiting, stomach cramps , and diarrhea — which may be bloody 9 , 10 , The most commonly found harmful bacteria in ground beef are Salmonella and Shiga toxin-producing E. Outbreaks of infections related to these bacteria occur fairly frequently in the United States 1 , 3 , 12 , Salmonella and STEC are the most common bacteria associated with food poisoning from ground beef.
Cook the meat thoroughly to reduce your risk of infection.
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