What does frozen meat look like and why do meat products change color after freezing

The first trick is to look at the appearance.

If it is spoiled frozen meat, the longer it is frozen, the protein contained in the meat will be oxidized, and the color of the meat will change to red or dark red, and the redder and darker the frozen meat, the more you cannot buy it. If there are white or black spots on the surface of frozen meat, the meat is even more inedible, and a lot of metabolites have been produced in it, so it is inedible.

When buying frozen fish, the eyes of the fresh frozen fish look pure, the scales on the fish body are complete, the body of the fish is elastic and will not sink down, and the belly of the fish is white and not black, so the frozen fish is relatively fresh.

The second trick is to smell the smell.

Spoiled frozen meat will smell rotten, we can pick up the meat and put it on our nose when we buy frozen meat, there is no smell, the same is true for frozen fish, some merchants will process spoiled frozen meat, and use a lot of spices, peppers, salt and other seasonings to cover up the taste of spoiled meat, so try not to buy this kind of pickled raw meat.

The third trick is to touch it with your hands.

Touching it with your hands is a technique to live, after the fresh frozen meat is thawed, the meat is also very tight and not loose, and it will be restored to its original appearance immediately after pressing, the meat is elastic, the meat is relatively dry, and there is a greasy feeling when touched by hand, but it is not sticky, if it is spoiled meat, the surface of the meat feels sticky, and some unscrupulous merchants will inject some water into it to ensure the elasticity and moisture of the meat, at this time, you can press the surface of the meat by hand, if there is more water on the surface, it is not fresh meat.

These 3 tricks are also applicable to frozen beef and chicken, if you are buying imported frozen meat, you must see whether there is a quarantine mark, production date, and production batch number.

Batch and other qualified documents, these are available, but also check whether the appearance is complete, whether there is damage, if the packaging is damaged, do not buy, to prevent contamination.

In daily life, we should try to buy fresh meat or refrigerated meat, if we want to buy frozen meat, we should observe more carefully, carefully select, do not buy meat from unknown sources, and go to regular supermarkets and vegetable markets.

and other places to buy, choose regular brand meat.

In our daily life, try to eat the meat as soon as possible, if you need to freeze, you can cut the meat into small pieces, freeze them separately, take out a small piece of thaw every time you eat, do not thaw repeatedly, so that it is not fresh and destroys the nutritional value of the meat, and the preservation time should not be too long, and it should be eaten as soon as possible, otherwise it will pass the frozen shelf life. Finish.

Discolored, melted into minced meat, do not eat to avoid poisoning.

The color becomes darker. Fresh meat has a shiny surface and uniform color. Fresh pork is red or light red, and the fat is white; The color of beef and mutton is bright red, and the fat is mostly yellow; Poultry meat** is pale yellow or white, and the meat is white and reddish.

With longer storage time, the flesh color will gradually turn reddish-brown due to the oxidation of myoglobin. The darker the color, the less edible it is. And when the surface of the meat turns gray or gray-green, or even white or black spots appear, it means that the microorganisms have produced a large number of metabolites, and such meat cannot be eaten.

The surface is sticky. Fresh meat is slightly dry or moist on the outside, slightly moist on the cut surface, oily to the touch, but not sticky; After the meat is spoiled, due to the large number of microorganisms, sticky metabolites will be produced, causing the surface of the meat to be sticky and even stringy. Sticky meat is a sign of the beginning of spoilage.

Elasticity deteriorates. Fresh meat is tight and elastic and heals immediately when you press the indentation with your fingers. The longer it is stored, the protein and fat in the meat will gradually be decomposed by enzymes, and the muscle fibers will be destroyed, so the meat will lose its original elasticity, and the depression after finger pressure will not only not be completely restored, but will even leave traces.

There is a peculiar smell. Fresh meat has a normal meat taste, while spoiled meat has an obvious rancid smell due to the decomposition of proteins, fats, and carbohydrates by microorganisms, which will produce various amines, indoles, acids, ketones and other substances.

Poor elasticity, high viscosity, peculiar smell, mixed broth. If the meat has a foul smell or peculiar smell, press the meat pieces with your fingers, the depression cannot bounce up, the color of the meat is dark, and the surface is filthy and sticky, such meat must be spoiled meat.

The color is dark, the red obviously turns dark red, and it feels sticky to the touch, which is spoilage.

See if the color changes color, see if there is a taste.

BecauseMyoglobinThe color is dark in the case of freezing and lack of oxygen.

Meat turns black after freezing because myoglobin is the main factor that affects the color of meat, and the color of fresh and cured meat depends on myoglobin, but the color of myoglobin is more likely to change. The color of the meat can be transformed into each other. Myoglobin and oxymyoglobin can change color by losing an electron to form methemoglobin (oxidation).

A common manifestation of abnormally frozen meat products.

Discoloration: The color of frozen meat will gradually darken due to its own changes, but if it is contaminated by microorganisms such as Pseudomonas and Leuconostoc, the surface of the meat will produce yellow, red, purple, blue, green, brown and other pigments. Once spoilage, it should be forbidden to eat.

Moldy: Some psychrophilic molds can multiply and grow even under freezing conditions at 20 years. If frozen meat has been stored for too long or has been contaminated during processing, these molds can form moldy spots, usually white spots, on the surface of the meat.

Dryness: After the frozen meat is stored for too long, especially after repeated freezing and thawing, a large amount of water in the meat is lost, which makes the frozen meat dry up, and the meat is sponge-like, and the protein and fat in the meat are seriously oxidized, and the nutritional value is reduced, so it is not suitable for consumption.

Taste change: Frozen meat has an off-flavor after drying, mainly due to the rancid smell caused by fat oxidation. In addition, if meat is stored and transported in the same warehouse or vehicle with odorous food and articles, it will have an odor due to the absorption of foreign odors.

Thawed meat generally spoils after about 6 hours at room temperature, and bacteria that like to grow and multiply on meat, and grow fastest when it is hot. If it takes a little longer to thaw, the meat may not be fresh or even spoiled. Careless consumption is very harmful to the human body.

After the pork is bought from the wet market, it needs to be stored in the refrigerator. It is important to note here that the pork is kept in the refrigerator. It is to be placed in the freezer, not the refrigerator.

When I put the pork in the freezer. Before putting it in, you need to cut the pork into small pieces and wrap the pork in plastic wrap, so that the pork will not lose its original nutrition.

Frozen meat can be stored for up to 6 months, and frozen things will not spoil if kept frozen, and will spoil if they are thawed repeatedly halfway.

First of all, the meat is kept in the freezer for up to 6 months.

However, it is recommended not to thaw the meat repeatedly, as this will reduce the taste and quality of the meat and breed microorganisms.

Refrozen meat, that is, meat that has been thawed for two or more times and repeatedly frozen, generally speaking, the quality will be greatly reduced, because the thawed meat at room temperature microorganisms enhance the fecundity and enzyme activity.

It is not resistant to storage after rising and re-freezing, and is easy to deteriorate.

If you buy too much meat at one time, you can divide the meat that needs to be frozen into several portions and store it, and only thaw one part each time you need it, so that there will be no problem of repeated thawing or re-freezing and spoilage.

In fact, not all food can be stored in the refrigerator, and there are some foods that are not suitable for refrigerator storage.

1. Honey. When honey is stored in the refrigerator, glucose will be precipitated.

Crystallization, although it will not affect the nutritional value, will affect the taste, and some people will think that the honey has deteriorated and throw away the honey, resulting in waste.

2. Chocolate.

Chocolate will be stored in the refrigerator will undergo a startling change of fat crystals, and like honey, it will not spoil, but it will affect the taste.

3. Tropical fruits.

Tropical fruits such as mangoes and bananas are suitable for storage at a temperature of around 12, but leaving them in the refrigerator will cause them to spoil.

If frozen meat goes bad, there are generally the following ways:

1.Put it at room temperature: Put the frozen meat at room temperature, in the room temperature environment, bacteria will move, will produce a lot of heat and various harmful substances, so that the frozen meat will spoil.

2.Keeping it in a hot and humid environment: Keeping frozen meat in a hot and humid environment will soften the proteins in the meat, making the meat more susceptible to rotting.

3.Add organic solvents: When organic solvents are added to frozen meat, Zhiyun will decompose the white matter of eggs in the meat, so that the frozen meat will deteriorate.

4.Placed in an environment with residual harmful substances: If it is placed in an environment with residual harmful substances, it will also spoil the frozen meat.