Is it OK to leave oat milk out overnight?

Oat milk has become an increasingly popular plant-based milk alternative in recent years. Its creamy texture and mild flavor make it a tasty choice for coffees, smoothies, cereals, and more. But there are some important food safety considerations when it comes to storing oat milk properly.

The basics of oat milk storage

Like dairy milk, oat milk is perishable and can spoil if left out at room temperature for too long. The proteins and sugars in oat milk make an ideal environment for bacteria to multiply quickly if given the chance.

So how long can oat milk be left out before it goes bad? General food safety guidelines recommend throwing away plant-based milk like oat milk if it’s been left out at room temperature for more than 2 hours. Bacteria grow most rapidly in the “danger zone” between 40°F and 140°F. Leaving oat milk out overnight would easily exceed the recommended 2 hour window.

Signs that oat milk has spoiled

If you accidentally leave a carton of oat milk on the counter overnight, check for the following signs of spoilage before drinking it:

• Sour odor
• Curdled texture or separation
• Mold on surface

Spoiled oat milk may develop a distinct sour smell as bacteria start to grow and produce acid. You may also notice the texture becomes curdled, chunky, watery or slimy as proteins coagulate. If any mold appears on the surface, it is also a clear sign the oat milk has spoiled and should be discarded.

Foodborne illness risks

Consuming spoiled oat milk can potentially lead to foodborne illness. Bacteria like Bacillus cereus, Staphylococcus aureus, and certain molds can produce toxins that cause symptoms like:

• Nausea and vomiting
• Abdominal cramps and diarrhea
• Fever

People with weakened immune systems, older adults, young children and pregnant women may be at higher risk for foodborne illness from spoiled dairy or plant-based milks. If you suspect oat milk sickness, discard the carton immediately and contact a healthcare provider if severe or persisting symptoms develop.

How to store oat milk properly

To get the longest shelf life and avoid spoilage, here are some tips for storing oat milk:

• Check “best by” date on carton and use within 5-7 days of opening.
• Keep refrigerated at 40°F or below after opening.
• Store unopened shelf-stable oat milk cartons in cool, dry pantry.
• Keep opened cartons towards front of fridge where it’s coldest.
• Don’t store in door of fridge where temperature fluctuates.
• Keep lid tightly closed between use.
• Don’t return unused milk back to carton after pouring.
• Use clean utensils to dispense milk.

Following proper refrigeration and using good hygiene practices will help prevent bacterial growth and keep your oat milk fresher longer.

Can spoiled oat milk make you sick?

Yes, consuming oat milk that has spoiled can make you sick. Like dairy milk, oat milk can harbor dangerous bacteria when left out at room temperature overnight or longer. Bacteria multiply rapidly in the danger zone between 40°F and 140°F.

Common symptoms of foodborne illness from spoiled milk include:

• Nausea
• Vomiting
• Abdominal cramps
• Diarrhea
• Fever
• Headache

Some bacteria that can grow in spoiled milk produce toxins that cannot be destroyed through cooking or boiling. Consuming spoiled or contaminated oat milk can cause a toxic infection.

How long does oat milk last once opened?

Once opened, oat milk will generally last 5-7 days in the refrigerator if stored properly between 35°F and 40°F. The shelf life depends on the type of oat milk:

Oat Milk Type	Refrigerator Life After Opening
Shelf-stable oat milk	7-10 days
Refrigerated oat milk	5-7 days
Barista-style oat milk	7 days

Make sure to check the “best by” date and never use oat milk past the recommended shelf life. Use your senses too – if it smells sour or shows separation, it’s safest to discard it.

Tips for longer lasting oat milk

To maximize the shelf life of opened oat milk:

• Store in back of refrigerator furthest from door.
• Keep oat milk carton lid closed tight.
• Check expiration dates and use oldest first.
• Don’t return unused milk from glass back into carton.
• Keep refrigerator temperature at or below 40°F.
• Clean spills immediately to avoid bacterial growth.
• Use clean utensils each time dispensing milk.

Avoiding contamination and temperature abuse will help keep your oat milk fresh and safe to drink before it expires.

Can you freeze oat milk?

Yes, freezing is an effective way to extend the shelf life of oat milk. To freeze:

• Make sure carton is securely sealed.
• Leave about 1/2 inch of headspace to allow for expansion.
• Flatten carton so it can stack neatly in freezer.
• Freeze at 0°F or below.
• Use within 3-4 months for best quality.

Thaw frozen oat milk cartons in the refrigerator overnight before use. Give it a good shake once thawed and pour into a glass before drinking. The texture may be slightly thinner after freezing.

Is it safe to cook or bake with spoiled oat milk?

No, it is unsafe to use spoiled oat milk in cooked or baked goods. The bacteria that cause spoilage can survive being heated or cooked. Consuming foods made with spoiled ingredients could still make you sick.

Additionally, using spoiled oat milk will negatively affect the flavor, texture, appearance and overall quality of anything you cook or bake. Spoiled milk may curdle, ruining the consistency of smoothies, cream sauces, oatmeal and more.

Always use fresh, unspoiled oat milk measured into a separate container instead of pouring directly from the carton when cooking or baking. Never taste or consume cooked foods made with spoiled oat milk.

Should you smell or taste test oat milk before using?

It’s not recommended to rely on smell or taste alone to determine if oat milk is safe to consume. Bacteria that cause illness do not always produce obvious changes in odor or flavor in the early stages of spoilage. Small amounts of contaminants or toxins may not be detectible.

The safest approach is to check expiration dates, store oat milk properly, and look for obvious signs like curdling or mold before use. When in doubt, remember the old adage – if it smells funky, looks chunky, or you’re unsure – throw it out to be safe.

Conclusion

Leaving oat milk out on the counter overnight exceeds the 2 hour safety window and provides opportunity for bacteria to multiply to dangerous levels. Consuming oat milk that has been left out too long can potentially cause foodborne illness.

To avoid getting sick, always refrigerate oat milk promptly after use and throw away any cartons left out for more than 2 hours. Check for signs of spoilage like odor, texture changes, or mold. Follow proper storage guidelines and oat milk should stay fresh for 5-7 days past opening.

While it’s not recommended, if you accidentally leave your oat milk out overnight, when in doubt, throw it out. Don’t take risks with your health.