Foods not to freeze

Before freezing food, consider the impact of low temperatures on its flavor and texture.

"Freezing tends to break down the structure of food", said Keith Warriner, a professor of food science at the University of Guelph, Ontario, Canada.

According to him, some foods can change significantly after freezing. For instance, mayonnaise may separate its oil. Fried foods like fried chicken can also lose their crispness as oil seeps out.

Whole eggs can crack as the water inside freezes and expands. For foods heavily dependent on texture, such as lettuce, bean sprouts, sprouts, and mushrooms, ice crystals formed during freezing can break down cell structures.

Fresh vegetables can still be frozen, but blanching them first is advisable. This process helps inactivate enzymes that can cause vegetables to darken and degrade quality during storage.

Storage time depends on the type of food. According to guidelines from the US Department of Health, many foods can be stored in a freezer for at least one to two months while maintaining quality.

Foods commonly stored for this duration include bacon, sausages, deli meats, and pies like pumpkin and pecan.

For cooked foods:

Soups and stews: two to three months.

Cooked meat or poultry: two to six months.

Leftovers like pizza or fried chicken pieces: one to three months.

For raw meats:

Chicken: 9 months for pieces, one year for whole.

Ground beef, turkey, or chicken: three to four months.

Beef, pork, lamb, or veal, including steaks, chops, and roasts: 4 months to one year.

These timelines primarily relate to food quality, not when food immediately becomes unsafe.

"There is no microbial growth when water is frozen, but chemical reactions, such as rancidity and moisture loss from freezer burn, still continue", Warriner said.

Therefore, storage times are only guidelines. Vacuum-packed food often retains quality longer than food in plastic bags with more air.

How to freeze food to maintain quality

The more air inside the packaging, the faster food quality deteriorates. Therefore, use airtight packaging like ziplock bags, removing as much air as possible, or vacuum-sealed bags.

This packaging method helps limit moisture loss. When water in food freezes and turns into vapor, food can develop dry, discolored areas, commonly known as freezer burn.

"Air, specifically oxygen, can also initiate the rancidity process in oils, causing off-odors and flavors", Warriner said. According to him, even though this process occurs more slowly when food is frozen, chemical reactions still continue.

Food that is rancid or has unusual odors or flavors should not be eaten. Some compounds formed during spoilage can cause illness.

Nhat Minh (via Simple Recipe)