How To Defrost Frozen Meat Correctly

By Author: Jack Guo
Total Articles: 5
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Hot Fresh Meat

Hot fresh meat means that livestock and poultry are slaughtered and processed, and sold directly in a fresh state after passing the sanitary inspection. Usually slaughtered in the early morning and marketed in the early morning without any cooling treatment. In the process from processing to retail, hot fresh meat may not only be polluted by air, flies, transport vehicles and packaging, but also the temperature of the meat is higher during this process, and bacteria are most likely to multiply. But there are also excellent masterpieces of hot fresh meat, most of which are niche dishes. For example, restaurants such as hot lamb and Chaoshan beef hot pot, but slaughtering and transportation require extremely high time, like a race against time.

The safer way to preserve meat is to store it at low temperature and carry out acid removal treatment. Because of the different temperatures used, the low-temperature storage method of meat can be divided into cooling method (chilled meat) and freezing method.

When it comes to cooling, there is a very popular name "refrigerated preservation". It refers ...
... to the storage of meat at a constant temperature of 0℃to 8℃. At the same time, the deacidification process of meat is being completed. The hot fresh meat mentioned above is very susceptible to microbial contamination and spoilage. However, if the livestock is slaughtered and cooled in time, the temperature of the meat will drop to 0℃-4℃ within 24 hours, and the temperature will always be maintained during a series of processing, circulation and sales in the future, which can inhibit the meat. The activity of the enzymes and the growth and reproduction of most microorganisms change the fiber structure of the meat, making it easier to chew and digest, the absorption and utilization of nutrients is also high, and the taste is better. This is called the deacidification process of meat.

If this cold storage process is carried out in a vacuum packaging belt, it is also called "wet ripening".

As the chilled meat is not completely frozen, there are still low-temperature bacteria in the muscles, so the storage period is far less than that of frozen meat. The shelf life of frozen meat can be as long as two years. why?

Frozen Meat

Large frozen block meat are usually processed by industrial meat processing machines like frozen meat flaker or frozen meat dicing machine.
Frozen meat refers to the pre-cooling of meat products at a temperature below minus 18℃for several hours, and the temperature of the deep-seated meat should at least reach below minus 6℃. Most of the water (above 80%) in the meat forms ice crystals, and the volume of the meat will increase after freezing. In this way, the meat storage time can be greatly extended.

Better quality "frozen meat" has strict requirements for storage temperature. For example, due to a series of objective factors, the factory equipment is limited and the cold storage temperature is not low enough. In the process from fresh meat to frozen meat, the freezing speed is too slow, which will cause the blood (cell fluid) inside the muscle to flow out.

It should be known that when the meat is frozen, the ice crystals formed in the muscle must exert a certain mechanical pressure on the muscle tissue. The rapid freezing at minus 40℃, due to the smaller and denser frozen crystals generated, is relatively small compared to the resulting pressure. And because muscles have a certain degree of elasticity, rapid freezing will not cause muscle tissue to be damaged and strained. But if it freezes slowly, the freezing environment is around minus 18℃, and some even can't reach minus 18℃. Then the ice crystals formed in the fleshy fibers will inevitably be large in volume and unevenly distributed. Therefore, the pressure generated by the ice crystals will also be very large, which will cause damage and destruction of the tissue structure. At the same time, it will oppress the fiber assembly. This type of tissue destruction phenomenon is mechanical and therefore irreversible. Sometimes ice crystals are so big that they can be seen clearly by the naked eye. Such meat will inevitably cause a large amount of blood (cell fluid) loss after thawing.

To translate the above paragraph in layman's terms, it means: frozen meat stored above minus 18℃ is not good and easily damages the meat quality. The meat that is frozen at minus 40℃ will be much better. Most meat slaughter plants in the United States use a rapid freezing process at minus 40℃.

Therefore, the stipulated shelf life of most domestic frozen meat can only be within one year. The shelf life of high-end imported frozen meat like American beef and pork is as high as 2 years! Fully doubled!

In this way, a piece of qualified frozen meat can extend the shelf life of meat compared to chilled meat (chilled meat). At the same time, as long as you defrost it correctly, it will hardly affect the flavor and nutrition of the meat. Therefore, for a piece of frozen meat, it is just fresh meat that is dormant.

The shelf life of frozen meat depends on factors such as the preservation temperature, the way of packaging, the type of meat, and the fat to lean ratio. The lower the preservation temperature, the better the protection of meat quality. If the packaging method is a sealed vacuum, the effect is better. If it is stored in a non-sealed vacuum, the cold air will directly invade the surface of the muscle. Over time, the surface of the muscle will eventually become air-dried and discolored. The water in the meat will evaporate and drain in a low temperature environment, forming a spongy body on the muscle surface. If left in this way for too long, the ice crystals under the sponge-like layer will continue to evaporate and sublimate, passing through the surface layer as water vapor, so that the sponge-like layer will continue to deepen.

Unless there is an "ice-packing" process on the surface of the meat, an ice layer is formed on the surface of the muscle to prevent the surface of the muscle from being directly invaded by cold air, just like putting a thick armor on the meat.

To fully achieve the goal of not affecting the quality and flavor of the meat after thawing, the efforts of the factory alone are not enough. The end customer also needs to do one thing when cooking meat: it needs to be defrosted in the correct way.

If you do not pay attention to the "thawing" part, then when frozen meat is thawed, the ice crystals in the muscle cells will pierce the cell membrane, resulting in the loss of "gravy". Both the nutritional value and taste and flavor will be affected. From a macro point of view, the meat will become very loose and difficult to handle. After cooking, there is no meaty taste, and the taste will be very woody. If you repeatedly freeze and thaw, the difference will be more obvious.

What is the Correct Way to Defrost?

First, the meat should be slowly thawed in an environment with a relatively small temperature difference. For example, if a piece of meat at minus 18℃​is thawed in an environment of 0℃ to 4℃, the temperature difference is about 22℃. If it is thawed at room temperature, the normal temperature is generally around 26℃. That is the temperature difference of 44℃! This will inevitably cause a large loss of blood (cell fluid), and the flavor will also be destroyed. And if it is slowly thawed in an environment with a small temperature difference, the juice ice crystals between the meat cells and the cells will slowly dissolve, and if there is time for it to gradually infiltrate the cells, the water loss rate after thawing will be small, even close to zero. In this way, the meat can return to the state of fresh meat to the greatest extent.

To put it simply, just move a piece of frozen meat together with the packaging bag directly from the freezer compartment to the refrigerator compartment as close as possible to zero℃ to thaw. As long as you give it enough time to thaw, the tender and moist meat will wake up from this!

I am a part-time writter in food industry. My full time work is doing food machines exporting business at Kingston Machinery. It is the top manufacturer and exporter of food processing machines in China. That is to say, we are a China-based factory-direct company for exporting of all kinds of food machines including meat processing equipment, nut machine, kitchen equipment and fruit/vegetable processing machine.