How to tell If buttermilk is bad? (5 ways how)

In this article, we will answer the question: “How to tell If buttermilk is bad?”, we will discuss the health implications of eating bad buttermilk and how to store buttermilk to avoid spoilage.

How to tell If buttermilk is bad?

To determine if buttermilk has gone bad, you can use your senses of sight, smell, and taste. Here are five common indicators to look out for:

Important: You should not eat spoiled buttermilk, especially if it was not pasteurized, as it can contain harmful microorganisms that can cause different health problems and foodborne diseases (1-5).

  1. Mold: Spoiled buttermilk will develop mold on the surface and near the lid of the container. Moreover, spoiled buttermilk undergoes discoloration and it is pretty obvious to tell.

You should be very careful with molds on your buttermilk as they can produce different mycotoxins that can make you very sick (6).

  1. Texture: Spoiled buttermilk will develop a large clump that will not be able to dissolve when whisked. Moreover, it will become too clumpy and thick to pour. 

Note that fresh buttermilk has small lumps naturally and it is not to be confused with spoilage.

  1. Taste: Buttermilk should taste tangy with a creamy and buttery mouthfeel. However, if that is not the case and it tastes too sour, the buttermilk has gone bad.
  1. Smell: If the buttermilk smells extra sour, it has gone bad. However, a newly opened container of buttermilk smells extra sour. Therefore, do not rely on the smell alone to detect spoilage.
  1. Expiration date: Buttermilk that is 1 week past its expiry should not be consumed. It has become unsafe and should be avoided to protect one’s health.

Can you get sick from eating spoiled buttermilk?

Yes, consuming spoiled buttermilk can lead to different foodborne illnesses (1-5). Remember that your buttermilk typically has a shorter shelf life than regular milk due to its natural acidity (7). 

The presence of harmful pathogens in spoiled buttermilk can cause various symptoms, such as:

  • Gastrointestinal issues: Consuming spoiled buttermilk can result in stomach discomfort, nausea, vomiting, diarrhea, and abdominal cramps. Pathogens like Salmonella, Escherichia coli, and Campylobacter can be responsible for these symptoms (1-3).
  • Food poisoning: If harmful bacteria such as Staphylococcus aureus or Clostridium perfringens contaminate buttermilk and multiply to dangerous levels, they can produce toxins that lead to food poisoning (8). Symptoms may include severe abdominal pain, diarrhea, vomiting, and fever.
  • Listeriosis: Listeria monocytogenes is a bacterium that can grow in certain conditions and cause listeriosis (9). 

This infection can result in symptoms such as fever, muscle aches, headache, stiff neck, confusion, and in severe cases, it can affect pregnant women, newborns, and individuals with weakened immune systems (10).

It is worth mentioning that while these pathogens are potential risks associated with spoiled buttermilk, it is essential to follow proper food storage guidelines and adhere to the expiration dates to minimize the chances of consuming spoiled or contaminated dairy products.

What should you do if you suspect you have eaten spoiled buttermilk?

If you have consumed spoiled buttermilk and you are experiencing symptoms or suspect food poisoning, here are some general recommendations:

  • Monitor your symptoms: Pay attention to any signs of gastrointestinal discomfort, such as nausea, vomiting, diarrhea, or abdominal cramps. Note down the time of onset and the severity of symptoms.
  • Stay hydrated: Drink plenty of fluids to prevent dehydration caused by diarrhea and vomiting. Water, clear broths, and electrolyte solutions like oral rehydration salts can be helpful (11).
  • Seek medical attention if necessary: If your symptoms are severe, persistent, or accompanied by high fever, bloody diarrhea, or signs of dehydration (e.g., excessive thirst, dry mouth, dizziness), it is advisable to seek medical help promptly.
  • Report the incident: Inform your local health department or relevant food safety authority about the suspected food poisoning. They can investigate and take appropriate measures to prevent further cases.

Remember that it is always best to err on the side of caution when it comes to foodborne illnesses. 

If you have any doubts about your health or the severity of your symptoms, consult a healthcare professional for proper advice and treatment.

How to store buttermilk to extend its shelf-life?

  • To extend the shelf-life of buttermilk, it is important to handle it using clean hands. Drinking directly from the buttermilk carton can introduce bacteria into the buttermilk that can lead to spoilage.
  • Do not place the buttermilk container in the fridge door because this area suffers the most temperature fluctuations. Ensure the storage of buttermilk at a steady temperature of 4.4°C.
  • After using, never place the buttermilk on the counter at room temperature. Put it back into the fridge immediately after pouring out the amount needed.
  • Switch to powdered buttermilk if you do not want to waste buttermilk to spoilage. Powdered buttermilk can be stored at room temperature and is suitable to use in baking.

How long does buttermilk last?

Buttermilk will stay good for 1-2 weeks past the sell-by date. This is not to be confused with the expiration date. The shelf-life of the buttermilk largely depends on how it was handled and stored (7). 

After opening, if the buttermilk is not to be consumed within 1-2 weeks, it is best to freeze it.

Freezing extends the the-life of the buttermilk. It is better to use frozen buttermilk as soon as possible. Because after 3-6 months of frozen storage, buttermilk undergoes irreversible and undesirable textural changes. 

Buttermilk must be refrigerated at all times to ensure its safety and quality. The following table shows an estimate of the shelf-life of buttermilk under different storage conditions:

In the fridge 
Buttermilk (unopened) 1-2 weeks past the Sell-by date 
Buttermilk (opened)1-2 weeks


In this article, we answered the question: How to tell If buttermilk is bad?. We also discussed the health implications of eating bad buttermilk and how to store buttermilk to avoid its spoilage?References:

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8. El-Bassiony TA. Occurrence of Clostridium perfringens in Milk and Dairy Products. J Food Prot [Internet]. 1980 Jul [cited 2023 May 23];43(7):536–8. Available from: 

9. Schaack MM, Marth EH. Survival of Listeria monocytogenes in Refrigerated Cultured Milks and Yogurt. J Food Prot [Internet]. 1988 Nov [cited 2023 May 22];51(11):848–52. Available from: 

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