肉包装里为什么会积出那么多水？不一定就是人为注水

Meat and poultry are composed of naturally occurring water, muscle, connective tissue, fat, and bone. People eat meat for the muscle. The muscle is approximately 75% water (although different cuts may have more or less water) and 20% protein,

When meat and poultry are frozen, the water that is a natural component of all meats turns to solid ice crystals. The water expands when it freezes. The sharp-edged crystals push into the surrounding tissue, rupturing the cells. The water that is outside the cell membrane freezes first. As it does, it leeches water from inside the cell membranes. When it thaws, the original balance does not return to normal. The thawed product will have lost some of its natural springiness. The water released during freezing seeps out of the thawing meat and poultry into the package.

Some meat and poultry products are vacuum-packed to prolong the storage times. Products are packaged in air- and leak-proof packages under vacuum, and, in some cases, a specific gas will be pumped into the package to preserve flavor and quality. While the package sits in the refrigerator case, the vacuum is still in effect, extracting the juices out of the meat. Because these packages are airtight and leak proof, the juices accumulate in the package. In contrast, the plastic wrapped packaging, typically used by most supermarkets, allows a certain amount of evaporation.

Many grocery stores offer meat and poultry products that have flavoring solutions added into them. For example, pork chops may be injected with a solution of water, salt, and sodium phosphate (a solution that can add flavor and moisture to leaner meats).