The Short Answer
No, sour cream should not be left out at room temperature overnight. Sour cream is a dairy product that can spoil and grow dangerous bacteria if left unrefrigerated for too long. The USDA and food safety experts recommend discarding sour cream that has been left out for over 2 hours at temperatures above 40°F.
What Happens When Sour Cream Sits Out Overnight
Sour cream is a cultured dairy product made from cream. Like milk, yogurt, and other dairy foods, it can spoil and grow harmful bacteria if left unrefrigerated. Here’s a look at what happens when you leave sour cream out overnight:
- Bacteria starts multiplying. Sour cream contains lactic acid bacteria that fermented the cream to give it its tangy flavor and thick texture. When kept cold, these bacteria are dormant. But leaving it out allows them to grow rapidly.
- Pathogenic bacteria may start growing. In addition to the natural lactic acid bacteria, contamination from the environment or cooking utensils can introduce pathogenic bacteria like E. coli, Salmonella, and Staphylococcus aureus to the sour cream.
- It spoils and changes taste/texture. The growing bacteria causes sour cream to spoil. It develops an off taste and odor. The texture also becomes more watery and changes from thick to runny as fats break down.
- Toxins are produced. Harmful bacteria like Staph produce toxins that can cause food poisoning. The toxins are not destroyed by cooking.
How Long Can Sour Cream Sit Out?
Sour cream should not be left out of refrigeration for more than 2 hours at temperatures above 40°F according to food safety recommendations. Here are some general guidelines for how long sour cream can be left out:
- 1-2 hours: Generally safe if used immediately after.
- 2-4 hours: Risky – use immediately or discard.
- Over 4 hours: Unsafe – discard immediately.
- Overnight (8+ hours): Very unsafe – discard immediately.
The exact time sour cream can stay out depends on factors like the room temperature and how much it was handled/exposed during serving. On a hot summer day, it may spoil in less than 2 hours. When in doubt, it’s best to err on the side of caution and discard sour cream that has been left out for over 2 hours.
How to Tell if Sour Cream is Bad After Sitting Out
Watch out for these signs that indicate sour cream has spoiled and should be discarded after sitting out too long:
- Liquid has separated from the cream and it becomes watery
- Change in color – it darkens and becomes yellowish
- Mold growing on the surface
- Off odors like sour, buttermilk, or ammonia
- Change in taste – sour, bitter, or unpleasant flavors
Sour cream that smells or tastes bad is contaminated with high levels of spoilage bacteria. Do not taste it or use it in cooking, even if reheating may reduce bacteria levels. The toxins produced by bacteria cannot be destroyed by cooking.
Can Spoiled Sour Cream Make You Sick?
Yes, consuming spoiled, out-of-date sour cream that has been left out overnight can make you sick. Here are some of the common foodborne illnesses it can cause:
- Staphylococcus aureus – Causes nausea, vomiting, stomach cramps, and diarrhea. The bacteria produce a heat-stable toxin that is not destroyed by cooking.
- Salmonella – Causes diarrhea, fever, and abdominal cramps that start 8 to 72 hours after consuming contaminated food. Can be life-threatening in infants, elderly, and those with weakened immune systems.
- Listeria monocytogenes – Causes fever, muscle aches, nausea, and diarrhea. It can be fatal in high-risk groups like pregnant women and newborns.
- Escherichia coli (E. coli) – Causes severe stomach cramps, diarrhea, vomiting, and fever. Some strains of E. coli can lead to kidney failure.
Food poisoning usually causes symptoms within 1 to 3 days of eating contaminated food. See a doctor immediately if you develop severe food poisoning symptoms like diarrhea lasting over 3 days, bloody stool, high fever, dehydration, or vomiting that prevents keeping liquids down.
How to Store Sour Cream Properly
To prevent spoilage and foodborne illnesses, sour cream must be stored properly. Follow these tips for safe sour cream storage:
- Refrigerate after opening – Keep sour cream chilled at 40°F or below after opening. Do not return it to the pantry.
- Use by expiration date – Discard if sour cream has passed the date printed on the container, even if refrigerated.
- Check for signs of spoilage – Look for mold, off-smells, separation, or a change in color/texture before consuming.
- Store in original container – Keep sour cream in its original cup or tightly sealed container.
- Freeze for longer storage – For prolonged storage, freeze extra sour cream for up to 2-3 months.
Can You Save Sour Cream After Leaving it Out?
Sour cream that has been left out at room temperature for over 2 hours should not be saved. The bacteria levels may be high enough to cause food poisoning, even if you refrigerate it after. It’s best to discard sour cream left out overnight.
Do not taste sour cream to check if it’s still okay. Smelling is also not foolproof, as spoiled dairy may not smell bad initially. When in doubt, just throw it out.
Should You Throw Away the Whole Container?
If you accidentally left the sour cream container out overnight, you should discard the entire container. Even if just a portion of sour cream was left out, bacteria can spread through the whole container. Erring on the side of caution protects you against foodborne illness.
Do not try to scoop out just the top layer that was exposed. Bacteria could have spread into the sour cream underneath even if it looks okay. The safest option is to discard the entire container of sour cream.
Can You Use Spoiled Sour Cream in Cooking/Baking?
It is risky and not recommended to use spoiled, out-of-date sour cream in cooking or baking. The high heat may kill some bacteria, but it does not destroy the toxins produced by bacteria that make you ill.
Also, the heat can break down the toxins into compounds that may be more dangerous. Consuming cooked spoiled dairy remains unsafe. Simply discard sour cream that has been left out too long.
Should You Avoid Open Dairy and Cream-Based Foods After?
If sour cream was left out overnight, you should also inspect and evaluate any other open dairy products like milk, yogurt, cream cheese, cottage cheese, or salad dressings. Discard any that may have also been left unrefrigerated for over 2 hours.
Check your refrigerator temperature as well. If multiple products were accidentally left out, it may indicate your fridge is not cold enough. Adjust to ensure it maintains 40°F or below.
How to Prevent Sour Cream from Spoiling
Practice proper food handling and storage methods to keep sour cream safe and prevent spoilage:
- Refrigerate unused sour cream immediately after opening.
- Keep sour cream on ice if serving it out for long periods.
- Use clean utensils each time you take sour cream out.
- Put unused portion back in the fridge within 2 hours.
- Always check expiration dates before use.
- Store unopened containers in the coldest part of the fridge.
- Keep fridge temperature at 40°F or below.
- Discard if any mold, smells, or changes are noticed.
The Bottom Line
Sour cream should never be left out at room temperature overnight. The prolonged time out of refrigeration allows dangerous bacteria to multiply to unsafe levels that can cause food poisoning. Discard sour cream if left out more than 2 hours. Refrigerating it afterward does not make it safe to eat.
To enjoy the flavor and creaminess of sour cream without the safety risks, always store it sealed in the refrigerator after opening. With proper handling, it can keep up to 2-3 weeks past the sell-by date printed. But when in doubt if sour cream is past its prime, don’t risk getting sick – play it safe and throw it out.
