How to Cool Foods Using the Two-Stage Cooling Method
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Cooling food after its been hot-held may seem as simple as leaving it on the counter for a while or putting it right in the fridge.
However, neither of these methods is a safe way to cool foods and can make your leftovers unsafe.
Instead, you need to follow what’s known as the two-stage cooling method to cool foods safely.
This article explains everything you need to know about the two-stage cooling method and why it’s important to prevent foodborne illnesses.
The two-stage cooling method
Cooling hot-held or cooked time and temperature control for safety (TCS) foods quickly is an important food safety principle.
This is because food passes through the temperature danger zone during its cool-down.
The temperature danger zone is 41ºF (5ºC) to 135ºC (57ºC). Pathogens that cause foodborne illnesses like bacteria multiply rapidly in this temperature zone.
Thus, food should spend at little time in the temperature danger zone as possible to prevent bacteria from rapidly multiplying and making people sick.
To limit the amount of time food spends in the temperature danger zone, you should follow the two-stage cooling method.
As the name suggests, this method happens in two stages (1).
In the first stage, you must cool foods from 135ºF (57ºC) — the minimum temperature at which foods must be hot held — to 70ºF (21ºC) within two hours.
Then, cool from 70ºF (21ºC) to 41ºF (5ºC) within four hours to complete the second stage.
Food must be cooled quicker during the first stage since bacteria multiply more rapidly between 70ºF (21ºC) and 135ºF (57ºC).
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The entire process should take six hours or less. If you cannot cool foods to 41ºF (5ºC) within six hours, you must recondition the food by reheating it to 165ºF (74ºC) and then try again.
The reconditioning process kills any bacteria that grew during the cooling process.
Use a calibrated food thermometer like a bimetallic thermometer to monitor the temperature as the food cools and then document it in a cooling log.
Keep cooling logs on file as inspectors will want to see them if a foodborne illness outbreak is traced back to your restaurant or food service operations.
Improper cooling practices contribute to a high number of foodborne illness outbreaks (2, 3).
The two-stage cooling method reduces the temperature of food from 135ºF (57ºC) to 70ºF (21ºC) within four hours and from 70ºF (21ºC) to 41ºF (5ºC) within two hours.
Ways to properly cool foods
Leaving food on the counter with no action is an unacceptable cooling method since the food may not reach 41ºF (5ºC) within six hours.
Also, never put large amounts of hot food in the refrigerator. Doing so can raise the inside temperature of the unit, and consequently, the other items inside, to unsafe temperatures.
Cold storage is designed to keep your foods cool, not chill them.
Unfortunately, one study reported that of the 420 restaurants observed, 361 did not follow the correct procedures for cooling foods (2).
There are three acceptable methods for cooling foods (1):
- Set up an ice-water bath. Place food in a prep sink — never a handwashing sink — or a large pot that is filled with ice water.
- Stir the food. Use an ice paddle — a plastic paddle that you fill with water and freeze — to stir the food frequently.
- Use a blast chiller. As the name suggests, these blast food with cold air to quickly lower their temperature. Blast chillers are used primarily by larger food operations due to their high costs.
You can also add cold water or ice to soups, stews, stocks, brines, and other liquids to cool them more quickly. To do this, make these items with less water and then add water or ice after it’s finished cooking to cool.
Even with these methods, it can be difficult to cool foods to 41ºF (5ºC) within six hours when you’re working with large amounts of food.
You can speed up the process by separating dense or liquid items like casseroles, mashed potatoes, rice, and soups into shallow pans (3″ or less in depth) and cutting thick items like roasts into smaller pieces (4).
Doing these things allows heat to dissipate or escape more rapidly.
Additionally, stainless steel containers transfer heat away from food faster than plastic and may be a better choice for cooling.
You can leave the containers uncovered if there is no risk of contamination from overhead, otherwise, keep them loosely covered to allow more heat to escape.
Remember to verify that your chosen cooling method or methods are effective by monitoring and documenting food temperatures during the cooling process.
To cool food safely and quickly, you can set up an ice water bath, use an ice paddle to stir the food, or use a blast chiller. You can also make liquid foods like soups with less water with the intent to add water or ice after cooking to cool it faster.
How long do leftovers last?
After you cool your leftovers safely, you should know how long to keep them before you must serve or toss them.
Refrigerating food slows the growth of pathogens but it doesn’t stop it.
Therefore, there is a limit to how long you can keep leftovers before they go bad.
You can safely store leftovers for up to seven days — appropriately known as the 7-day rule — if it is held at 41ºF (5ºC), with the day of cooking counting as the first day (1).
So if you cooked rice, for example, on October 1st, you would need to serve or toss any leftovers by October 7th at the latest based on the 7-day rule.
If you don’t plan to sell or serve leftovers within seven days, it’s best to freeze them to halt bacteria growth.
However, if you store leftovers in the refrigerator before moving them to the freezer, you still need to count those days — as well as the date of preparation — as part of the 7-day rule.
Label any leftover food with its name, the date prepared, and the date it should be served, sold, or tossed if you plan to hold it longer than 24 hours.
Store leftovers on the top shelf in the refrigerator or freezer.
You can safely store leftovers for up to seven days if it is held at 41ºF (5ºC) or below, with the day of preparation or opening counting as the first day.
The bottom line
The two-stage cooling method ensures that food cools to safe temperatures within a certain time.
Using this method, you must cool foods from 135ºF (57ºC) to 70ºF (21ºC) within two hours and then from 70ºF (21ºC) to 41ºF (5ºC) within four hours.
To speed up the cooling process, you can set up an ice water bath, stir the food regularly, use a blast chiller, or make soups, brines, and other liquids with less water with the intent of adding water or ice after cooking to cool them.
You can safely store leftovers for up to seven days, just make sure to label the food with its name, the preparation date, and the date it needs to be served or tossed if you plan to hold it longer than 24 hours.
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