If you’ve ever assembled your own salad, you’ve probably popped open a jar of commercial mayonnaise or a bottle of store-bought dressing. Maybe you wondered what to do after opening them. You aren’t alone. Does mayo need to be refrigerated? Does salad dressing need to be refrigerated? Thankfully, these are fairly easy to answer. In addition to exploring the shelf life of mayo and how long other store-bought salad dressings last after opening, we’ll also cover whether or not homemade dressings can be stored unrefrigerated, and for how long.
Table of Contents
- Does Mayonnaise Need to Be Refrigerated?
- What Happens if Mayo Is Not Refrigerated?
- How Long Can Mayo Sit Out Unrefrigerated?
- Does Mayo Need to Be Refrigerated Before Opening?
- How Long Can Salad Dressing Be Left Unrefrigerated?
- Why Does Salad Dressing Need to Be Refrigerated?
- Does Homemade Salad Dressing Need to Be Refrigerated?
- What Salad Dressings Do Not Need Refrigeration?
- Is Salad Dressing OK If Left Out Overnight?
- How Do You Store Salad Dressing?
- How Long Does Salad Dressing Last After Opening?
- Refrigerating Other Salad Dressings
- Does Mayonnaise and Salad Dressing Need to Be Refrigerated? Most of the Time, Yes!
- FAQs
Does Mayonnaise Need to Be Refrigerated?
Yes, mayo should be refrigerated to maintain its freshness and quality. This is because pantry staple mayonnaise contains eggs and other perishable ingredients that can spoil if left at room temperature for an extended period.
Unopened mayonnaise can be stored in a cool, dry place until the expiration date on the package. Once unsealed, the opened mayo should be refrigerated at a temperature below 40°F (4°C) and used within 1-2 months.
Does Homemade Mayonnaise Need to Be Refrigerated?
Yes, homemade mayonnaise should be refrigerated. The homemade version mayonnaise typically contains raw egg yolks and oil, which have an even shorter shelf life (with few preservatives) than commercial mayo. They spoil quickly, especially if left at room temperature.
Once prepared, homemade mayonnaise should be stored in an airtight container in the refrigerator at a temperature below 40°F (4°C). Use within a week for best quality.
You can increase the shelf life of your homemade mayonnaise through safe handling and making sure it’s stored safely. Use clean utensils and work in a clean environment to reduce the risk of contamination.
What Happens if Mayo Is Not Refrigerated?
Mayo contains eggs and other perishable ingredients that can promote the growth of bacteria at room temperature. When left out for an extended period, the bacteria can multiply rapidly and cause the mayo to spoil.
Therefore, if mayo is not refrigerated, it can spoil and become unsafe to eat.
How Long Can Mayo Sit Out Unrefrigerated?
Mayo should not be left out unrefrigerated for more than 2 hours. Do not leave it unrefrigerated overnight.
Mayonnaise contains perishable ingredients like eggs and oil that can promote the growth of bacteria when left at room temperature. If mayonnaise is left out unrefrigerated for more than two hours, it can spoil and become unsafe to eat.
Refrigerate mayonnaise promptly after use and discard any that has been left at room temperature for more than 2 hours. Avoid leaving your mayonnaise dressing out in hot and humid environments or in direct sunlight.
If you’re unsure whether your jar of mayo has been left out for two or more hours, it’s best to err on the side of food safety and discard it.
Does Mayo Need to Be Refrigerated Before Opening?
Mayonnaise does not need to be refrigerated before opening if it is commercially produced and sold in shelf-stable packaging.
However, it’s always best to check the label for storage instructions.
Do You Have to Refrigerate Mayonnaise After Opening?
Yes, it is recommended to refrigerate mayo after opening. This maintains its freshness and extends its shelf life. Mayonnaise contains perishable ingredients like eggs and oil, which can spoil if left at room temperature for a long time.
Once opened, mayonnaise should be refrigerated below 40°F (4°C). Your opened mayo must be used within 2 months.
How Long Can Salad Dressing Be Left Unrefrigerated?
The short answer is 2 hours. This is in compliance with the two-hour rule as set forth by the USDA.
However, there is a little more to it than that.
Depending on the ingredients in your salad dressing, you may be able to get away with storing your dressing after a few hours has passed. Or even not storing it at all!
Dressings that are made with dairy (ingredients that are milk and cream relatives) or that have fresh ingredients in them, such as dressings that are homemade, will need to be refrigerated right away once used. This is especially true if the dressing you bought was refrigerated upon purchase.
If, however, the bottle of dressing you bought is sealed and was purchased at room temperature, you will only need to refrigerate that dressing once it is open.
(By the way, if you’re wondering about salad’s shelf life in the fridge, I have a blog post on that, too!)
Why Does Salad Dressing Need to Be Refrigerated?
Salad dressing doesn’t always have to be refrigerated. If the dressing only contains non-perishable items – like oil and vinegar with salt and pepper, for example – then this can be stored at room temperature for a few months at best quality. For example, salad oil (that is just pretty much oil), can get away with not being refrigerated a while.
Most dressings, however, will require refrigeration of some sort. That is because most dressings contain fresh vegetables (onions, roasted peppers, etc) or other ingredients (like dairy) that require constant refrigeration, especially once exposed to air.
As previously mentioned, bottled dressings that were purchased at room temperature can stay that way even up to a few months past the best by date printed on the label. This is provided that the bottle of dressing was never opened.
A dressing that was purchased refrigerated, however, must stay that way. These types of dressing typically do not contain many preservatives like those that were sold on the shelves. They are, therefore, more prone to spoilage.
Does Homemade Salad Dressing Need to Be Refrigerated?
Homemade salad dressing typically needs to be refrigerated, if the dressing contains fresh vegetables or dairy. If the dressing only contains vinegar and oil, then refrigeration might not be necessary.
If you aren’t sure, place your salad dressing in the fridge and use it up within a week of making it. Better to err on the side of safety rather than to take the risk of contracting food borne illnesses.
What Salad Dressings Do Not Need Refrigeration?
Salad dressings that do not need refrigeration include those that contain only oil, vinegar, and non-perishable spices. Some people choose to leave store bought dressings out at room temperature after opening because they know they contain preservatives.
While it is true that dressings bought at room temperature contain preservatives to keep them fresh this way, it is also true that breaking the seal on salad dressing exposes it to air. This can lead to bacteria growth.
As such, it is imperative that your dressing be stored safely in the fridge after opening, even if you purchased a dressing that was sitting on the shelf at the store.
Is Salad Dressing OK If Left Out Overnight?
Unless your salad dressing is a simple dressing that only contains non-perishable ingredients, you may need to throw away any opened or fresh dressings that have sat out overnight.
As air and moisture reach your dressing, bacteria begin to form and multiply. The longer the dressing sits out, the more dangerous the dressing will be.
The reason that storing the dressing in the fridge is ideal rather than leaving it out, is because the refrigerator slows the process of decay. Therefore, placing your dressings in the refrigerator quickly after opening prevents unhealthy mold and bacteria from growing in your dressing. Refrigeration also allows the dressing to stay useable until the best by date.
Note: As always, be sure not to consume any dressing that has changed in color, taste, texture, or consistency.
How Do You Store Salad Dressing?
The best way to store your salad dressing will depend on the type of salad dressing you have.
Use the following guidelines for each type of salad dressing:
- Homemade Salad Dressing: Homemade version dressings have few preservatives. Store in an airtight container or tightly sealed glass jar (even a well-sealed squeeze bottle) for up to one week. Vinegar only or oily dressings may be stored in an airtight container at room temperature.
- Store-Bought Salad Dressing From Shelf: Store in its original container at room temperature until ready to use. Once you’ve opened the bottle, you’ll need to store this type of dressing in the refrigerator until the best buy date.
- Refrigerated Store-Bought Salad Dressing: Store in its original container in the fridge until ready to use. After use, you must immediately place it back in the refrigerator to keep it fresh until its best by date.
How Long Does Salad Dressing Last After Opening?
Salad dressing that has been left open will last about 2 hours before beginning to grow bacteria if it is store-bought and was purchased refrigerated. Any other opened dressings, including those that are homemade, should be refrigerated no more than a few hours after having been used.
All dressings should be thrown out if left overnight, with the exception of those made from simple and non-perishable ingredients, such as oil and vinegar.
Refrigerating Other Salad Dressings
Does Oil and Vinegar Dressing Need to Be Refrigerated?
Opened oil and vinegar dressings do not need to be kept in the fridge if those are the only two ingredients in the dressing.
However, if there are any sliced vegetables in the dressing, such as diced peppers or onions, you will need to refrigerate this sort of dressing.
Does Italian Dressing Need to Be Refrigerated?
Yes, you will need to refrigerate Italian dressing within 2 hours of having opened it.
If the squeeze bottle was sold at room temperature and is unopened, it will keep at room temperature for up to a few months past its best by date.
Does French Dressing Need to Be Refrigerated?
French dressing does typically need to be refrigerated once exposed to air. That said, French dressings that were bought already refrigerated should be stored in the refrigerator immediately. Keep French dressings of all types in the fridge once opened until the printed best by date.
Does Ranch Dressing Need to Be Refrigerated?
Ranch dressing should certainly be stored in the fridge once opened because of its dairy ingredients. A bottle of ranch that isn’t open and was sold on the shelves won’t need refrigeration until opened. But a bottle of ranch that was purchased refrigerated must be kept refrigerated to prevent spoilage.
Read more about ranch expiring in my blog!
Does Balsamic Vinegar Dressing Need to Be Refrigerated?
Surprise! Balsamic vinegar does not, technically, have to be refrigerated.
Like everything else, refrigeration lessens the amount of bacteria occurring in the vinegar. But generally, balsamic vinegar, on its own, will stay safe at room temperature.
Note: Once you’ve added other ingredients to balsamic vinegar to make it into a dressing, you’ll need to store the dressing in the fridge for up to a week to preserve it. Bottled balsamic vinegars that contain a wide variety of ingredients should also be stored in the fridge once open.
Does Mayonnaise and Salad Dressing Need to Be Refrigerated? Most of the Time, Yes!
Most of the time, you will find that your salad dressings require refrigeration, especially once opened. There are some caveats to this, however. These will determine whether or not your salad dressing will remain safe for consumption if left out.
Don’t be afraid to make your regular salad, potato salad, or pasta salad, using mayo or dressing. As long as you make sure your pantry staple condiments and dressings are still safe to eat.
FAQs
Does Opened Salad Dressing Need to Be Refrigerated?
Yes, opened salad dressing typically needs to be refrigerated to prevent spoilage and bacterial growth. Most salad dressings contain perishable ingredients like oil, vinegar, or dairy products, which can go bad if left at room temperature for an extended period.
Does Salad Dressing Need to Be Refrigerated?
Salad dressings that contain dairy or have fresh ingredients in them, such as homemade dressings, should be refrigerated right away once used. You will also need to refrigerate dressing that you bought if it was refrigerated upon purchase.
If, however, the bottle of dressing you bought is sealed and was purchased at room temperature, you will only need to refrigerate that dressing once it is open.
How Long Can Salad Dressing Be Left Unrefrigerated?
The easy answer is 2 hours, but you can get away with certain dressings sitting at room temperature for a few hours. To be safe, refrigerate your opened and used salad dressing.
Does Hellman’s Mayonnaise Have to Be Refrigerated After Opening?
Yes, Hellmann’s Mayonnaise should be refrigerated after opening to maintain its freshness and quality. It’s safe to say this goes the same for commercially produced mayonnaise.
Does Duke’s Mayo Need to Be Refrigerated?
Yes, Duke’s Mayo should be refrigerated. This is because Duke’s contains perishable ingredients like eggs and oil that can spoil if left at room temperature for an extended period.
Does Best Foods Mayo Need to Be Refrigerated?
Yes, like all traditional and commercial mayo, Best Foods Mayo should be refrigerated to maintain its freshness and quality. It contains ingredients that are milk and cream relatives, which are easily perishable.
How Long Does Mayo Last?
The shelf life of this go to cooking ingredient varies depending on its type and storage. Unopened mayonnaise in a shelf-stable container can last a year or more if stored in a cool, dry place away from direct sunlight. Mayonnaise in a homemade salad or sandwich should be consumed within two hours of preparation if left at room temperature. If stored in the refrigerator, mayo can last 3-4 days.
It’s important to note that the actual shelf life of homemade or commercially produced mayonnaise can vary depending on the brand, storage conditions, and other factors. When you buy mayonnaise, check the expiration date and follow the storage instructions on the package.
Can Expired Mayonnaise Give You Food Poisoning?
Expired mayonnaise can potentially give you food poisoning and food borne illnesses if it has gone bad and is contaminated with harmful bacteria such as Salmonella, Listeria, or E. coli.
