What happens if I drink expired oat milk?

Oat milk has become an increasingly popular plant-based milk alternative in recent years. Made from soaked oats and water, it has a creamy, mild flavor that makes it suitable for drinking, baking, and adding to coffee and cereals. However, like other plant-based milks, oat milk does have an expiration date that indicates when it may no longer be safe to consume.

What is the shelf life of oat milk?

The shelf life of oat milk depends on whether it has been opened or not. Unopened, commercially packaged oat milk typically lasts 5-10 days past its printed expiration date when stored properly in the fridge. Once opened, oat milk should be consumed within 7-10 days.

The shelf life is shortened once opened because exposure to oxygen and repeated contact with containers and utensils creates opportunities for spoilage. The expiration date is based on the assumption that the product will be kept refrigerated and the package will remain sealed.

How can you tell if oat milk is expired?

Watch for the following signs that opened oat milk has gone bad:

  • Sour smell
  • Thick, ropey, or chunky texture
  • Mold on surface
  • Fizzing or bubbling when shaken
  • Change in color

Oat milk is naturally thick with a creamy consistency, so a slightly thicker texture alone does not necessarily mean it has expired. However, oat milk that has truly gone bad will have an unpleasant sour smell and may be chunky or curdled. It may also be carbonated when shaken if gases from spoilage microbes have built up inside.

Can expired oat milk make you sick?

Drinking oat milk a few days past its expiration date is generally safe, especially if it has been stored sealed in the refrigerator. However, oat milk that has truly spoiled has a higher risk of containing harmful bacteria that could cause food poisoning. Consuming expired oat milk more than 2 weeks past its printed date is not recommended.

Some of the common bacteria that can contaminate oat milk and cause illness include Bacillus cereus, Staphylococcus aureus, and certain strains of Salmonella and E. coli. Drinking contaminated oat milk could lead to symptoms like:

  • Nausea and vomiting
  • Abdominal cramps and diarrhea
  • Fever
  • Headache

Symptoms may range from mild to severe depending on the amount consumed, your age and health status, and the type of bacteria present. Severe cases can lead to hospitalization. Vulnerable groups like pregnant women, infants, young children, and those with compromised immune systems are at highest risk for foodborne illness.

How long does oat milk last once opened?

Here is a table summarizing how long oat milk lasts once opened if stored properly in the refrigerator:

Type of oat milk Lasts for
Plain oat milk 7-10 days
Flavored oat milk (vanilla, chocolate, etc.) 5-7 days
Barista edition oat milk 7 days

As you can see, plain oat milk has the longest shelf life after opening, lasting about 7-10 days in the fridge before expiring. Flavored versions only last 5-7 days since added flavors like chocolate, vanilla or strawberry shorten shelf life. Barista blends optimized for foaming and steaming also have a shorter 7 day shelf life opened.

How to store oat milk correctly

To get the most shelf life out of your opened oat milk, be sure to store it properly:

  • Keep refrigerated at 40°F or below
  • Store in the fridge door rather than on fridge shelves
  • Keep away from light and heat sources like oven vents
  • Screw lid tightly to prevent oxygen exposure
  • Keep the opening and dispensing utensils clean
  • Don’t return unused milk from glass/cup back into carton

Avoid temperature fluctuations and minimise exposure to light, heat and oxygen to retain quality and freshness for as long as possible after opening.

Can you freeze oat milk to extend its shelf life?

Freezing is an option for extending the shelf life of oat milk. To freeze:

  • Make sure milk is fresh and has not expired
  • Leave 2 inches of headspace in the container as liquids expand when frozen
  • Seal tightly and freeze immediately at 0°F or below
  • Once frozen, oat milk should last 6-8 months in the freezer

Frozen oat milk may become thinner and experience some separation after thawing in the refrigerator. Give it a good shake or stir before use. It may also have some change in texture and taste compared to fresh. But it will still be safe to consume as long as it was properly frozen before the expiration date.

Should you cook or bake with expired oat milk?

Using oat milk that has just passed its expiration date for baking or cooking is generally fine. The heat from cooking destroys most bacteria that could be present. However, oat milk with an off taste or separated texture may negatively impact the flavor and appearance of recipes. Curdled or spoiled milk may cause baked goods to rise unevenly or have a dense texture.

For best results, use oat milk that is as fresh as possible. Avoid using oat milk that is more than 2 weeks past date, smells sour, or appears curdled, separated or moldy. Make sure baked goods containing oat milk are fully cooked to an internal temperature of 165°F.

Is it safe to consume oat milk after its use-by date if it smells and looks fine?

It’s generally not recommended to consume oat milk past its use-by or expiration date, even if it still smells and appears normal. This is because harmful microbes like bacteria and mold can grow over time to dangerous levels without producing obvious signs of spoilage.

However, oat milk that is within 5-7 days past its printed date is less likely to contain dangerous levels of microbes, especially if it was properly stored in the refrigerator. Use caution and your best judgment – if it smells fine and has no signs of spoilage like mold, fizzing, separation, or unpleasant texture, oat milk slightly past its date is unlikely to cause illness if consumed immediately.

Can spoiled oat milk make pets sick?

Yes, spoiled and moldy oat milk can make dogs and cats sick. Off oat milk may contain harmful bacteria like Salmonella or E. coli that can be passed to pets and cause gastrointestinal illness. Ingesting oat milk with toxic mold can also cause illness.

Signs your pet may have become ill after consuming spoiled oat milk include:

  • Vomiting
  • Diarrhea
  • Loss of appetite
  • Lethargy
  • Dehydration

In severe cases, pets may need veterinary treatment with fluids and medications to recover. To keep your pets safe, be sure to discard oat milk once it expires or shows any signs of spoilage.


Drinking oat milk shortly after its expiration date is unlikely to cause harm, especially if it was properly stored sealed in the refrigerator. However, oat milk that is spoiled or moldy can harbor dangerous bacteria and should always be discarded. When in doubt, err on the side of caution – if oat milk smells odd, looks curdled, or is more than 2 weeks past its date, it’s safest to throw it out and not consume.

Storing oat milk correctly in a clean sealed container in the coldest part of the fridge is key to maximizing its shelf life after opening. Freezing oat milk can also extend its shelf life significantly. With proper storage and handling, oat milk can remain fresh, safe and tasty to consume for 5-10 days past its printed expiration date.

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