Introduction: Due to improvements in the environment for slaughter, transportation, and sales, it is now possible to sell chilled meat of better quality. Chilled meat, also known as cooled meat, is pork that is rapidly cooled (not frozen) after slaughter, with the carcass temperature reduced to 0-4°C within 24 hours, and maintained at this temperature throughout subsequent processing, transportation, and sales.
Characteristics of Hot Meat
Hot meat is the most traditional type of commercially available pork. It is fresh meat slaughtered at midnight and supplied to the market in the early morning. Because this meat retains a certain amount of body heat, it is called "hot meat".
The interval from slaughter to consumption for hot meat is relatively short. Its meat is often in the "rigor mortis" stage. When cooked, this meat is often difficult to tenderize, lacks juice, and is not easily digested and absorbed, thereby reducing its nutritional value.
In the summer, due to the high ambient temperature of the carcass, combined with the heat generated from the breakdown of glycogen within the meat, the meat's temperature can rise sharply, even reaching 40-42°C. This provides favorable conditions for bacterial growth, producing a foul "sweaty" odor.
This odor cannot be eliminated no matter how much seasoning is added during cooking. In the summer, a few hours after slaughter, the bacterial count in hot meat can reach "innumerable" levels. By the time it reaches the consumer, it may no longer fully comply with national health standards and could pose a food safety hazard.
Hot meat is only suitable for consumption after a longer period under low-temperature conditions in winter (including transportation, sales, and storage), when it enters the "aging" stage. This process produces more flavor substances such as amino acids and peptides. At this point, the processed meat products have a better taste and are easier to digest and absorb.
If you purchase hot meat that is in the "rigor mortis" stage, you can store it in the refrigerator's chill compartment for one day until it enters the "aging" stage before eating; the taste will be better. If a "sweaty" odor has already developed, it cannot be removed. Pork with a "sweaty" odor cannot be identified by its appearance. When buying hot meat, be sure to smell it first for any off-odors.
It is best to buy only as much hot meat as you plan to eat. If you buy a large quantity at once and cannot finish it, you will have to put it in the freezer, turning it into frozen meat. Due to the limited cooling capacity of household freezers, it is often not possible to ensure that the core of the frozen pork reaches the required low temperature for preservation. This not only fails to guarantee the quality of the meat but also wastes energy. Many housewives cut the hot meat they buy into slices, shreds, dices, or mince and store it in the refrigerator or freezer. However, this practice is not advisable.
Characteristics of Frozen Meat
Frozen meat is pork that is rapidly frozen after slaughter at a temperature below -25°C, and then stored at -18°C. Under these freezing conditions, bacteria do not multiply extensively, and enzyme activity is greatly reduced, allowing for long-term preservation. Because it is sold in a frozen state, it is called frozen meat, commonly known as "cold-air meat".
During the freezing process, because the freezer is a "dry box" that easily loses moisture, the meat loses water, the tissue shrinks, the fibers become coarser, the color darkens, and the fat tissue is partially oxidized. Moreover, during the freezing and thawing process of pork, the lost juices reduce protein and other nutrients in the meat by about 7%, and decrease flavor substances. Thus, frozen meat not only has slightly reduced nutritional value but also a poorer taste. If not handled properly, it may also develop an off-flavor.
Frozen meat must be thawed before cooking or processing into forms like salted slices, shreds, or dices. If you only need a portion of a large piece of frozen meat, you should cut off the required part and leave the rest to continue freezing. Do not thaw the entire piece and then refreeze it.
To eat frozen food that is similar in quality to fresh food, the frozen meat brought home should first be portioned according to the amount needed for each meal and placed in a freezer at -18°C or below. Thawed food should be processed and cooked as soon as possible and should not be refrozen, to prevent the loss of water and nutrients in the meat from repeated freezing and thawing.
Characteristics of Chilled Meat
Due to improvements in the environment for slaughter, transportation, and sales, it is now possible to sell chilled meat of better quality. Chilled meat, also known as cooled meat, is pork that is rapidly cooled (not frozen) after slaughter, with the carcass temperature reduced to 0-4°C within 24 hours, and maintained at this temperature throughout subsequent processing, transportation, and sales.
Because chilled meat is always kept in a cold chain, it can dissipate heat from the carcass (including its deep tissues) more quickly, and a dry film forms on the surface of the meat, slowing down the evaporation of moisture and thus preventing microbial growth and reproduction, which extends its shelf life.
Furthermore, during the glycolysis of glycogen in chilled meat, lactic acid is produced, which has an inhibitory and killing effect on microorganisms in the meat, making chilled meat safer and more hygienic.
Chilled meat requires a 2-day maturation period from slaughter to sale to enter the post-ripening stage. During this time, proteins break down into more peptides, amino acids, and flavor-enhancing nucleotides, making the meat tender, elastic, easy to cook, with a delicate texture, rich in umami and aroma, and its nutrients are easily digested and absorbed by the body. Additionally, because chilled meat has not been frozen, it does not require thawing, so there is no need to worry about nutrient loss.
In the cold chain, the fat oxidation process is also inhibited, preventing the formation of ketones, aldehydes, and other rancid substances, and the "sweaty" odor does not occur. The color of chilled meat is no different from that of fresh hot meat. Worldwide, chilled meat has gradually replaced hot meat and frozen meat, becoming the preferred fresh pork for consumers.
With the availability of chilled meat, people should buy only as much as they need and process it promptly, without freezing it for storage. If you buy a large quantity at once and cannot finish it, and then put it in the freezer, it becomes frozen meat. Whether in its original form or processed into slices, dices, or mince, it no longer possesses the advantages of chilled meat.