Sour cream is a dairy product that is commonly used as a topping or ingredient in many dishes. It has a cool, tangy flavor that can enhance soups, baked potatoes, tacos, and more. But because sour cream is a dairy product, it can spoil if left at room temperature too long. So what happens if you accidentally leave an open container of sour cream sitting on the counter overnight? Is it still safe to eat?
The Dangers of Leaving Dairy Out
Dairy products like sour cream can be breeding grounds for harmful bacteria when left out at room temperature. Bacteria grow rapidly between 40°F and 140°F. Since refrigerators are set to around 40°F and room temperature is around 70°F, dairy left out overnight enters the danger zone for bacterial growth.
Some common bacteria that can grow in sour cream left out include:
- Salmonella – Can cause salmonellosis food poisoning with symptoms like diarrhea, fever, and cramps.
- Staphylococcus aureus – Can cause food poisoning with vomiting and diarrhea.
- Listeria monocytogenes – Can lead to listeriosis which can be potentially fatal.
- E. coli – Certain strains can produce Shiga toxin leading to severe illness.
- Bacillus cereus – Causes vomiting and diarrhea type food poisoning.
In addition to bacterial growth, sour cream left out overnight will also start to undergo physical and chemical changes:
- It will begin to curdle and become more liquid-like as proteins start to break down.
- The texture changes from smooth and creamy to more watery and lumpy.
- The tangy, sour flavor starts diminishing.
- It starts emitting a rancid or spoiled odor.
These changes happen as bacteria ferment the lactose and proteins in the sour cream over time at room temperature. The increased bacteria, curdling, and rancid smells are all signs that sour cream is no longer fresh or safe to eat.
How Long Can Sour Cream Sit Out?
Dairy products should never sit out at room temperature for more than 2 hours. This is the recommended maximum time set by the FDA Food Code.
More specifically for sour cream, it should be discarded if left out beyond:
- 1-2 hours at temperatures above 90°F.
- 4-5 hours at temperatures between 40°F and 90°F
In general, the warmer your room is, the less time the sour cream has before it is considered unsafe. If your kitchen is very hot, the sour cream could potentially start growing dangerous bacteria in only an hour at room temperature.
What About Overnight in the Fridge?
If you accidentally left an opened container of sour cream in the refrigerator overnight, can you still use it? The fridge temperature, around 40°F, slows down bacterial growth significantly compared to room temperature.
An opened container of sour cream should last about 2 weeks in the fridge according to USDA guidelines. But it’s a good idea to throw it out after 7-10 days if you aren’t sure how long it’s been open.
As long as the sour cream was refrigerated properly overnight and hasn’t exceeded its recommended fridge life, it should be safe to use or consume.
How to Tell if Sour Cream is Bad
If you are ever unsure about the safety of an open container of sour cream, here are some tips for identifying if it has gone bad:
- Check the expiration date – This will give you an idea of how long it has been open.
- Look at the consistency – It should be smooth and creamy. Separation of liquid or curdling indicates spoilage.
- Smell it – Sour cream that has gone bad will have a rancid odor.
- Taste a small amount – Rancid or bitter flavors are a sign it should be discarded.
- Observe the color – Significant darkening from white to yellow or grey indicates spoilage.
As a general rule of thumb, if your sour cream exhibits any odd textures, colors, smells or flavors compared to a fresh tub – it is best to play it safe and throw it out.
Can Spoiled Sour Cream Make You Sick?
Eating sour cream that has sat at room temperature overnight can potentially make you sick. As discussed earlier, harmful bacteria like Salmonella, E. coli, and Listeria can multiply quickly at room temperature.
Consuming spoiled sour cream could lead to foodborne illness symptoms such as:
- Nausea
- Vomiting
- Diarrhea
- Abdominal cramps and pain
- Fever
- Headache
- Fatigue and muscle aches
Symptoms can appear anywhere from 30 minutes to 6 hours after ingesting contaminated sour cream. In some cases, food poisoning from bacteria in sour cream can even cause hospitalization.
At greatest risk are those with compromised immune systems such as older adults, pregnant women, young children and those with chronic illnesses. Listeria infection in particular can be very dangerous and potentially life-threatening for these high risk groups.
Even if sour cream left out overnight doesn’t make you immediately sick, it can still harbor bacteria that get transferred onto other foods. Any dishes you use the sour cream in like dips could lead to illness down the line.
How to Store Sour Cream Properly
To get the longest shelf life out of your sour cream and avoid potential food poisoning, follow these safe storage guidelines:
- Refrigerate after opening – Keep sour cream chilled at 40°F or below.
- Seal container tightly – Prevent leaks or spills that introduce bacteria.
- Use clean utensils – Don’t re-dip dirty utensils back into container.
- Avoid cross-contamination – Store away from raw meat that could pass pathogens.
- Check use-by date – Consume by expiration date on the packaging.
- Track date opened – Write the open date on containers for reference.
- Use within 7-10 days – Throw out opened sour cream after 1-2 weeks max.
Being diligent about proper refrigerated storage and using opened sour cream in a timely manner are the best ways to prevent foodborne illnesses.
Recap – Is it Safe to Eat Sour Cream Left Out?
In summary, it is generally unsafe to consume sour cream that has sat at room temperature beyond 2 hours. Leaving an opened container of sour cream on the counter or fridge door overnight allows harmful bacteria to rapidly multiply to dangerous levels.
Eating sour cream left out for more than 4-5 hours comes with a high risk of food poisoning. Symptoms like diarrhea, vomiting, and fever can begin shortly after ingesting contaminated sour cream.
Your risk level also goes up the warmer your home is, since bacteria thrive fastest at temperatures between 40°F and 140°F. If in doubt, remember the old adage “when in doubt, throw it out” applies here.
To avoid needing to discard sour cream, always seal and promptly refrigerate any leftovers. Use refrigerated opened sour cream within 7-10 days and stick to expiration dates. Follow the proper storage and handling guidelines to keep sour cream safe and reduce food waste.
