Ask a Food Safety Scientist: What Foods Should Always Be Refrigerated?

Recently, our food safety scientists received a question about what types of food need to be kept cold.

You may already know that it’s important to refrigerate certain foods to help prevent pathogen growth. But how do you know what does and doesn’t need to go in the fridge? Here are a few guidelines that can help you determine what foods should be refrigerated. We’ll also share a few tips for how to organize your fridge to keep food safer and fresher.

Time/temperature control for safety (TCS) foods

Food handler puts turkey in fridgeTime/temperature control for safety (TCS) foods are foods that are more vulnerable to pathogen growth. These foods contain a food source, like carbohydrates or protein, and moisture that bacteria need to grow. If allowed to stay in the temperature danger zone (41°F-135°F) for too long, pathogens can grow to a point that the food becomes dangerous to eat. They should always be stored in the refrigerator to keep pathogens from growing to dangerous levels.

Some common TCS foods include:

  • Milk and milk products, like cheese and yogurt
  • Eggs
  • Meat, poultry, fish, and shellfish
  • Cooked foods like vegetables, rice, and potatoes
  • Raw sprouts and cut leafy greens
  • Cut melons
  • Cut tomatoes
  • Garlic in oil

If your dish uses any of these foods as ingredients, you will also need to keep them cold. For example, potato salad usually contains mayonnaise, eggs, and cooked potatoes, so it needs refrigeration.

In addition, if any TCS food is left out at room temperature for four hours or more, it should be thrown away. Bacteria grows rapidly at room temperature, and it can reach dangerous levels in about four hours. If you eat food that’s been left out too long, it is likely you will get a foodborne illness.

Does butter have to be refrigerated?

Commercial kitchens should keep butter in the fridge to be extra safe, but it may surprise you to learn that home chefs don’t always have to refrigerate their butter. Even though it’s a milk product, the pasteurization process changes butter’s physical properties. After pasteurization, the water molecules in butter are separated by fat, which is almost impenetrable to bacteria and protects butter from microbial growth. Salted butter is even more resistant to pathogen growth.

Homemade butter or butter that hasn’t been pasteurized should always be kept in the fridge.

How long does food stay good in the refrigerator without power?

If your power goes out without warning, keep your refrigerator and freezer closed. Fridges will stay cold for about four hours while freezers will keep cold for about 48 hours.

Storing foods

When stocking your refrigerator or freezer, you should arrange foods by cooking temperature. Foods with lower cooking temperatures should be at the top, while foods that need to be cooked to higher temperatures should be stored at the bottom. Organizing your fridge this way will keep your food safer, since any bacteria that leaks from the food above will be killed as you cook the food below.

Ready-to-eat foods should be stored on the top shelf, followed by vegetables that will be cooked for 135°F, whole meats and seafood that will be cooked to 145°F, ground or mechanically tenderized meats that will be cooked to 155°F, and finally poultry, casseroles, and stuffed pastas that will be cooked to 165°F.

Date marking food

In addition to storing your food on the right shelves, you should keep it in the right order so that you use older food first and minimize your food waste. You’ll want to use the First In, First Out (FIFO) method.

After appropriately date marking your food, store it so that the oldest food is at the front with the newest at the back. That way, the first food you grab from the shelf is the one that needs to be used first. If you don’t use the food by its use-by date, be sure to throw it away immediately.

Thawing, heating, and reheating

In addition to storing fresh foods correctly, it’s important to thaw frozen foods correctly to prevent bacterial growth. Keep frozen foods out of the temperature danger zone as much as possible by using approved thawing methods. Safe thawing methods include thawing food in the refrigerator and running cold water over food. You can also use cooking equipment, like stoves and ovens, to reheat and cook food.

Cooling foods

When cooling food, follow the two-stage cooling process to keep it out of the temperature danger zone as much as possible. If you’re cooling a large batch of food, you can help it cool faster by splitting it up into smaller portions or putting it in an ice bath.

Remember to use a thermometer to check the temperature often when performing any of these activities to ensure that the food is thawed, cooked, reheated, or cooled properly!

Following these guidelines can help reduce your risk of foodborne illness. At the same time, you can reduce your food waste and improve your profits. Learn more about TCS foods and other good food safety practices in our online food handlers training course.

If you have any questions you’d like to ask our in-house food scientists, fill out this one-question survey!

— Janilyn Hutchings

Updated: May 30, 2019 — 4:04 pm
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