How long do restaurants keep frying oil?

  • By: Emma
  • Date: May 19, 2022
  • Time to read: 5 min.

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How long do restaurants keep frying oil?

Do you know how long the oil in your favorite restaurant is used in frying until it is changed? After all, it’s not like they tell you when you order food. Most people don’t even think about this and assume that they change their frying oil often enough to be safe. However, this is a big misconception!

You may not believe this, but most restaurants keep frying oil for months before changing it!

This blog post will teach you how long restaurants keep frying oil and what can happen if they don’t switch it out on time.

Read on!

Facts about restaurants keeping frying oil you want to know!

Restaurants reuse the same frying oil for much time, which is unhealthy. Of course, some restaurants fry their foods in newer oil, but that’s just because they want to spin you a story, not because the oil is fresh.  

Every day, a large part of America has their meals cooked in used cooking oil that’s been used for weeks, if not months!

Following are some facts about frying oil trends in restaurants you may have never heard before!

1. Oil filtration

Frying oil is not cheap, and to use the same oil for more extended periods, restaurants need to make sure that their cooking oil is clean enough to be reused. The only way to do this is by filtering out any debris or particles left in used cooking oil which takes time.

Hence, if you want a healthy and fresh diet, avoid eating fried foods in restaurants.   

2. Access to new oils on time

Many people think that whenever they see a restaurant reusing old frying oil, then it’s because they haven’t ordered new supplies. This is not the case.    

Many times, restaurants don’t receive their new oil delivery on time, forcing them to reuse old cooking oils.

3. Changing frying oil causes fire hazards

It takes a lot of time and effort to change out frying oils in restaurant locations because it involves draining all the used cooking oil from deep fryers, filtering out debris, and then refilling with fresh cooking oil again.

All this requires gasoline or other flammable liquids that pose serious fire threats if they are spilled.

Hence, changing prepackaged or filtered frying oil is just too risky for most restaurant managers to try!  

4. Most people care less about used oil

Yes, you can expect restaurants to fry your food in fresh cooking oil, but unfortunately, all except a few people don’t seem to mind. Most customers aren’t concerned about what they eat, and more or less, all of them expect restaurants to reuse old oil in frying foods.

That’s a fact restaurants know well! People are concerned about taste more than health and hygiene.

5. Additives for frying oil

Did you know that used frying oil can be made to look new with additives? There are many chemicals and other items which restaurants use to clean old cooking oils and make them look lovely again.

Of course, these chemicals are not suitable for your health, but they make used oil look like it’s fresh again. This is why you will never know for sure whether your favorite restaurant keeps frying oil or not!

6. Not all restaurants reuse old oil

Although many restaurants reuse old cooking oils in frying foods, some of them follow strict rules and regulations on when they should change frying oil.

Restaurants that change their cooking oil every week are the ones you should trust with your health!

7. Limit set by FDA

The Food and Drug Administration (FDA) regulates the number of times restaurants may keep their used cooking oil before changing it. According to their standards, restaurants must either recycle their frying oil or dispose of it somewhere off-site after seven days from when they started using it.

But that’s not the whole story. FDA doesn’t test any restaurant’s used cooking oil unless someone complains that there is something wrong with it!

What happens if restaurants don’t switch it out on time?

1. Bacteria accumulation

Remember that old oil can contain bacteria that may have grown inside the container or come from any small particles left in it after filtration. Exposure to this dirty cooking oil can cause severe diseases like E Coli.

So, If you are eating fried foods at a restaurant and the cooking oil has been used for more than seven days, it is best to be careful.

2. Peroxide Acids

If you are eating foods cooked in old cooking oil, you need to think twice because it often contains high levels of peroxide acids.

Peroxide acid is formed after exposure to air and increases cancer’s possibility. It can also cause skin problems like itching or rashes.

3. Cancer causing agents

Several dangerous cancer-causing agents accumulate inside used frying oil if it has been reused for more than a week.    

These dangerous carcinogens include Acrylamide, Acetone, Ethylbenzene, and many others, which absolutely no one wants to put into their bodies!  

4. Food Poisoning

If the oil is reused without filtration, there are certain types of diseases that you can get.

For example, if the oil is used for frying fish or meat, there is a good chance that you will suffer from food poisoning because fish and meat are naturally more prone to bacteria buildup.

5. Doesn’t taste good

Another reason why it’s not a great idea to eat fried foods made in old cooking oil is because it doesn’t taste right!

Old cooking oil doesn’t have any flavor, so no matter how to think or salty your french fries are, they won’t be able to cover up the burnt smell and weird taste.


The bottom line is that restaurants reuse oil for more days than you can imagine. Although the chefs must use fresh oils for frying, especially when customers expect delicious tasting foods, they aren’t so honest about it.

 If you ever dine at an unknown restaurant, it is strongly recommended to avoid fried foods. Remember that even if they claim the oil is fresh, you can never be sure how long it’s been used.

Prevention is better!

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