What will happen if you eat expired yogurt?

Quick Answers

Eating expired yogurt may cause minor gastrointestinal issues like stomach pain, nausea, vomiting, and diarrhea. The risk increases the longer the yogurt has been expired. Moldy, foul-smelling yogurt should be discarded. Most negative effects are temporary and resolve on their own. But infections or severe vomiting/diarrhea can require medical treatment. Those with compromised immune systems are at higher risk of illness.

What is Yogurt Expiration?

Yogurt expiration refers to the date after which the yogurt is no longer considered fresh and its quality and safety begin to decline. This date is determined by the manufacturer based on factors like the processing method and storage temperature. After the expiration date, bacteria can grow and spoil the yogurt, and nutrients like protein and probiotics may start to break down.

The expiration date is usually printed on the yogurt container with a phrase like:

  • “Best by”
  • “Sell by”
  • “Use by”
  • “Best before”

This is the last date recommended for use at peak quality. Some types of yogurt may still be safe to eat for 1-2 weeks after the expiration date if stored properly in the fridge. But quality declines as it passes peak freshness.

Why Can Expired Yogurt Make You Sick?

Eating expired yogurt increases the risk of foodborne illness because potentially harmful bacteria can grow over time. Fresh yogurt has cultures like Lactobacillus acidophilus that keep it safe. But as yogurt ages and sours, dangerous bacteria like Staphylococcus aureus, Salmonella, and E. coli can start to multiply, especially if the expired yogurt was left at room temperature or has mold.

Some of the potential health risks from spoiled, out-of-date yogurt include:

  • Food poisoning – Nausea, vomiting, diarrhea, fever
  • Gastroenteritis – Stomach pain, cramping, diarrhea
  • Listeriosis – Fever, muscle aches, confusion
  • Salmonellosis – Abdominal cramps, diarrhea, nausea
  • Staphylococcal food poisoning – Vomiting, diarrhea, abdominal pain

The older the yogurt, the higher the levels of bad bacteria may grow. While yogurt is acidic, which helps limit microbial growth compared to other dairy products, contamination can still occur and is more likely the longer yogurt is expired.

How Long After Expiration is Yogurt Bad?

It’s difficult to provide an exact timeframe for how long yogurt is safe after expiration. How quickly yogurt spoils depends on factors like:

  • Storage temperature – Yogurt lasts longer refrigerated vs. at room temperature
  • Type of yogurt – Pasteurized yogurt lasts longer than unpasteurized yogurt
  • Package seal – Tightly sealed yogurt lasts longer than yogurt resealed or left open
  • Fat content – Full-fat yogurt lasts longer than low-fat or fat-free yogurt
  • Preservatives – Yogurt with added preservatives maintains quality longer

As a general guideline:

  • Sealed yogurt stored in the fridge is likely safe 1 week past expiration
  • Yogurt 2 weeks expired should be evaluated before consuming
  • Yogurt over 2 weeks expired should be discarded

When refrigerated properly, the nutrients and probiotics in yogurt can remain relatively stable for about 1-2 weeks after expiration. But the taste, texture, and overall quality deteriorate rapidly. Yogurt that is moldy, watery, lumpy, or foul-smelling should always be thrown away regardless of the expiration date.

Does Expired Yogurt Go Bad?

Yes, expired yogurt can spoil and go bad. Over time, the live active cultures that give yogurt its thick, tangy flavor begin to die off. Enzymes start breaking down proteins and fats. This causes yogurt to smell sour, taste unpleasant, and develop a thin, watery texture.

The natural sugars in yogurt also ferment with bacteria, producing gas that leads to bloating of the package. Mold may start growing, which can appear as white, blue, green, or black spots.

While these obvious signs make spoiled yogurt unappealing, dangerous pathogens may also be present before strong odors or textures manifest. So it’s important to rely on the expiration date as a guide and be cautious once it has passed.

Can You Get Food Poisoning from Yogurt?

Yes, eating yogurt contaminated with bacteria, toxins, or mold can cause food poisoning. Symptoms like nausea, vomiting, stomach cramps, and diarrhea usually start 12-36 hours after ingesting harmful microbes from yogurt or other dairy products and last 1-3 days.

Food poisoning risk increases if yogurt is left at room temperature for too long, allowing microbial growth. Possible culprits include:

  • Staphylococcus aureus – Causes nausea/vomiting. From human handlers.
  • Salmonella – Causes diarrhea, fever, chills. From raw ingredients.
  • Listeria – Causes fever, fatigue, confusion. From processing equipment.
  • E. coli – Causes stomach cramps, bloody diarrhea. From cross-contamination.
  • Mold – Causes nausea, vomiting, diarrhea. From airborne spores.

Proper food handling and avoiding expired, contaminated yogurt reduces the risk of foodborne illness. But yogurt should not be consumed if you see any signs of spoilage or experience suspicious symptoms after eating it.

Common Symptoms of Eating Bad Yogurt

Here are some typical symptoms that may develop after consuming yogurt that has gone bad:

1. Nausea

One of the first signs of foodborne illness from expired yogurt is a queasy, uncomfortable sensation in the stomach and urge to vomit. Nausea typically starts 30 minutes to 6 hours after ingesting the contaminated yogurt.

2. Vomiting

Vomiting often follows nausea and involves forcefully expelling stomach contents up through the mouth. Vomiting from bad yogurt can begin quickly or take up to 12 hours after consumption.

3. Diarrhea

Frequent, loose, watery stools are common with food poisoning from bacteria or mold in spoiled yogurt. Diarrhea often accompanies vomiting and can lead to dehydration if severe.

4. Abdominal Cramps

Cramping pains and discomfort in the abdominal region are typical with foodborne illness. This symptom arises as the gastrointestinal tract tries to eliminate the infectious agents.

5. Fever

A moderately high body temperature over 100°F (37.8°C) may accompany yogurt-induced food poisoning as the immune system activates to fight infection. Young children are more prone to fever with gastrointestinal upset.

In healthy adults, these symptoms often resolve within 24-48 hours with rest and hydration. But infants, the elderly, pregnant women, and those with compromised immunity should seek medical attention for severe vomiting, diarrhea, dehydration, or high fever from food poisoning.

How to Know if Yogurt Has Gone Bad

Watch for the following signs that indicate yogurt is spoiled and should be thrown out:

1. Expiration Date Passed

As a rule of thumb, yogurt that is more than 1-2 weeks past the expiration date printed on the package is more likely to be unsafe to eat due to bacterial overgrowth.

2. Mold Growth

Visible mold growing on yogurt indicates the presence of fungi and associated mycotoxins that can cause illness. Mold often looks fuzzy and appears in shades of black, green, white, or blue.

3. Discoloration

Grayish, yellow, or brown discolored areas on yogurt can signal contamination by molds and yeasts. This spoiled yogurt should be discarded.

4. Gas Production

Yogurt containers that appear inflated or swollen have built up gas from microbial fermentation. The sealed gases can push up the container lid. Swelling or bloating of packaging shows the yogurt has spoiled.

5. Sour Odor

A strong, unpleasant sour milk smell indicates yogurt has turned bad. This rancid odor develops as bacteria convert lactose and proteins into smelly compounds.

6. Change in Texture

Separation of whey, slimy texture, or an atypically thin, watery consistency signals the yogurt is no longer fresh and has probably spoiled.

7. Strange Flavor

An overly tangy, bitter, or just “off” flavor can mean unhealthy bacteria are growing and producing waste products that alter the yogurt’s expected taste.

Trust your senses – if expired yogurt looks, smells or tastes bad, err on the side of caution and throw it away. Better to be safe than sorry if there is any doubt about possible contamination or spoilage.

What to do if You Eat Bad Yogurt

If you accidentally consume expired yogurt that tastes or smells strange, take these steps:

  1. Discard any remaining yogurt to prevent others from eating it.
  2. Note the expiration date and type of yogurt for reference.
  3. Call your doctor if you feel severely ill or have concerning symptoms.
  4. Drink fluids to prevent dehydration from vomiting/diarrhea.
  5. Get plenty of rest and eat bland, gentle foods once symptoms subside.
  6. Monitor for signs of dehydration or high fever that require medical treatment.
  7. Report severe food poisoning to the proper health department.
  8. In the future, check dates and always discard expired yogurt products.

Foodborne illness from yogurt is not extremely common. But anytime symptoms seem excessive or last longer than 48 hours, seek medical advice, especially if you are in a vulnerable population like the very young, elderly, pregnant, or immunocompromised.

How to Store Yogurt Safely

You can help yogurt last as long as possible by storing it properly. Here are some yogurt storage tips to minimize spoilage:

  • Always check expiration dates before purchasing and consuming.
  • Keep unopened yogurt refrigerated at 40°F (4°C) or below.
  • Eat yogurt by the “use by” date for best quality.
  • Refrigerate opened yogurt immediately and use within 7-10 days.
  • Do not store yogurt in the refrigerator door where the temperature fluctuates.
  • Keep different varieties of yogurt separate to prevent cross-contamination.
  • Make sure yogurt is not kept near raw meats that could leak juices.
  • Avoid introducing spoons/utensils into yogurt containers unless thoroughly cleaned first.
  • Do not let yogurt sit out on the counter unrefrigerated more than 2 hours.

Proper yogurt storage and handling helps prevent bacterial growth as well as mold. Always discard yogurt if there are any obvious signs of spoilage no matter how long it has been refrigerated.

Tips for Consuming Yogurt Safely

You can take these additional precautions when buying and eating yogurt to reduce your risk of foodborne illness:

  • Check for damage, dents, or swelling of yogurt packages before purchasing.
  • Avoid yogurt past its expiration date or not stored cold in the market.
  • Choose pasteurized yogurt when possible for extra safety.
  • Clean utensils and workspaces before handling yogurt.
  • Consume yogurt well before the expiration or “use by” date.
  • Never eat moldy or oddly colored yogurt.
  • Do not eat yogurt with an off smell or texture.
  • Discard any yogurt left out more than 2 hours.
  • Avoid sharing yogurt containers and spoons between people.

Being an informed consumer helps you choose safe yogurt products and store them properly. But it’s always smart to discard yogurt at the first signs of spoilage.

Who is at Higher Risk from Consuming Bad Yogurt?

While anyone can experience foodborne illness from eating expired yogurt, some populations have a higher risk for infection:

Young Children

Kids under age 5 have more vulnerable, developing immune systems and are prone to dehydration from vomiting and diarrhea.

Older Adults

Adults over 65 have weakened immunity and underlying medical conditions that make them more susceptible to becoming very ill.

Pregnant Women

Hormonal changes in pregnancy increase vulnerability. Certain bacteria like Listeria are especially concerning.


Those with chronic diseases like HIV/AIDS, cancer, diabetes, or autoimmune disorders are at increased risk of severe infection.

People in higher risk groups should take extra care to avoid consuming expired or contaminated yogurt products. Prompt medical treatment is key if they develop symptoms.

Can Babies Eat Expired Yogurt?

No, babies should never be given expired yogurt. An infant’s immune system is still developing, so foodborne pathogens can make them very sick. The bacteria, toxins, or mold from spoiled yogurt can easily overwhelm a baby’s body and lead to:

  • Dehydration
  • Malnutrition
  • Severe diarrhea
  • Fever-related seizures

Infants under 12 months old should not have any expired foods or beverages. Always check expiration dates carefully when feeding yogurt to babies. And never give a baby yogurt that smells odd or looks moldy, even if the date seems okay. When in doubt, throw it out.


Eating expired yogurt is generally mild in healthy adults but poses higher risks for vulnerable groups like children, pregnant women, the elderly, and immunocompromised. While some types of sealed yogurt may last 1-2 weeks past the expiration date if refrigerated, quality and safety diminish over time.

Yogurt can grow dangerous bacteria, mold, and toxins when expired and spoiled. Consuming contaminated yogurt can cause temporary gastrointestinal illness or even life-threatening complications. Look for visible signs of spoilage and avoid yogurt with strange odors, textures, or flavors.

Discard expired yogurt, especially if more than 1-2 weeks past the date. Proper yogurt handling and storage helps prevent contamination. Seek medical treatment for concerning or persistent symptoms after ingesting bad yogurt. When in doubt, throw it out!

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