Ensuring the Best Quality for Your Frozen Food
Zero Degrees F is the Optimal Storage Temperature for Frozen Food Safety
In terms of frozen food safety, it’s always good practice to hold food at 0 degrees Fahrenheit (-18 degrees Celsius) or lower. At those temperatures bacteria cannot grow, so food stays protected from the proliferation of microbes that cause foodborne illness, maximizing the length of time that food can be stored. If there’s one hard and fast rule for storing frozen food, it’s that 0 degrees Fahrenheit or lower is a safe storage temperature. That’s why most commercial freezers are designed to maintain temperatures around that number, usually lower to provide a little wiggle room to compensate for door openings, the addition of products, and defrost cycles. They also offer those lower settings for holding ice cream, which has an optimal storage temperature of -10 to 0 degrees Fahrenheit.
Just because food that is kept at 0 degrees Fahrenheit will remain safe indefinitely doesn't mean it should be held indefinitely. The quality of the food - meaning its texture, taste, and nutritional value - will degrade over time to the point that it becomes unappetizing or inedible. So how long does frozen chicken last? The United States Department of Agriculture's Food Safety and Inspection Service provides a useful cold storage chart that shows you the length of time foods can be kept frozen without suffering a loss in quality.
Be aware that not all products do equally well at 0 degrees Fahrenheit. If you're using a cook-chill system to prepare foods like soups and sides ahead of time, specifically delicate items or those with a high moisture content, you risk damaging products if you allow them to reach such low temperatures. As foods freeze, the water in them expands and turns into ice crystals. The formation of those crystals can cause damage to the product, negatively affecting the texture, flavor, and nutritional value of the product when it's thawed and reheated.
To avoid damaging more delicate foods, consider investing in a separate freezer for cook-chill products and other precooked foods that you'll be using within a few days of their initial preparation. Those products generally don't need to be much colder than 32 degrees Fahrenheit and they can be kept in a "slushy" state for several days.
Shorter Freeze Times = Better Food Quality
Those inevitable ice crystals we mentioned in the previous section can wreak havoc on the quality of your food, but it's possible to minimize the damage even if you need to store food at the subarctic temperatures required to keep food safe for more than a few days. See, the longer food takes to freeze, the larger those ice crystals tend to become, and larger crystals can do more damage to the quality of the food.
There are a few ways to speed the freezing process and ensure the best frozen food safety and quality.
- Avoid thawing and refreezing food. Your freezer really shouldn't be used to freeze large amounts of food from a non-frozen state, but rather to keep food frozen that you've received while it was frozen or frozen by another means. Plan accordingly to defrost only the food that you'll use within a day or two to avoid having to refreeze it.
- Invest in a blast chiller. Blast chillers are essentially extra-powerful freezers that are designed to bring foods down to safe storage temperatures quickly, getting them through the "danger zone" of temperatures where bacteria grows. This is the only reliable solution for an establishment looking to safely freeze food prepared in-house on a regular basis. Just be sure to pick one that's capable of freezing food; many are only designed to bring food down to refrigerator temperatures.
- Limit how much you put in the freezer at a time. If you absolutely must take food from a refrigerated or room-temperature state and freeze it, do it a little at a time. The higher the volume of non-frozen product that’s added to a freezer, the harder the freezer will have to work to get those down to temperature, and the longer it will take.
- Portion bulk products into smaller pieces or containers. If you're storing a big batch of chili, soup, or a similar dense product, portion it into containers of single or just a few servings. That will expose more surface area of the product to the cold temperatures within your freezer to help them get down to the target temperature faster.
"Keep Food Safe! Food Safety Basics." United States Department of Agriculture Food Safety and Inspection Service. Accessed August 2015.
Berry, B. W. and K. F. Leddy. "Effects of Freezing Rate, Frozen Storage Temperature, and Storage Time on Tenderness Values of Beef Patties." Journal of Food Science Vol. 54, Issue 2, pp 291-296. Accessed August 2015.
Frozen Food Handling and Merchandising. Frozen Food Handling and Merchandising Alliance. Revised 2009. Accessed 2015.