Can you get sick from eating expired butter? (2 reasons)

In this article, we are going to answer the question “Can you get sick from eating expired butter?” and discuss how can you get sick from eating expired butter, how to know if butter is spoiled, what is the shelf life of butter and how to store butter to improve its shelf life.

Can you get sick from eating expired butter?

Yes, you can get sick from eating expired butter. In addition to the possibility of experiencing a foodborne disease in the short term, eating expired butter can lead to a higher risk of developing inflammatory diseases in the long term (1, 3).

Although not common, butter can cause food outbreaks and has been reported to cause several cases of foodborne illnesses in individuals consuming garlic butter, salted and unsalted butter (2).

How can you get sick from expired butter?

You can get sick from eating expired butter in two ways. Butter is susceptible to contamination. While unsalted butter can support the growth of pathogens such as Escherichia coli, Listeria monocytogenes and Salmonella, salted butter can carry psychrotrophic bacteria (1). 

Unsafe storage practices and unhygienic production conditions are the most common causes of butter contamination. Even salted butter has been reported to cause episodes of food outbreaks, leading to diseases and hospitalisations (2).

The long-term consumption of expired butter can be harmful if the butter is oxidised. Oxidised fatty acids generate toxic products, such as ketones, aldehydes and peroxides which are genotoxic, mutagenic and carcinogenic (3). 

These toxic compounds may interfere with the function of the cells and cause cellular damage, leading to cell death, as well as DNA mutation. The ingestion of oxidised fatty acids is related to atherosclerosis, cancer and cardiovascular disease.

How to know if butter is spoiled?

To know if butter is spoiled, you should inspect its overall appearance, odour and flavour, although microbial contamination is not always detectable by evident signs. Some indications that butter is spoiled are the following (1, 2, 4):

Presence of off-odours or off-flavours: oxidised, such as cardboard-like, metallic, bitter, paint-like; rancid, such as decayed nuts, fishy or pungent; or sour, fermented, fruity or yeasty (as a result of spoilage caused by yeast). A musty off-odours may be due to the presence of moulds.

Altered texture: a greasy texture with a fast melting.

Colour change: growth of mould or spore-forming, black discolouration, coloured discolouration, surface taint.

What is the shelf life of butter?

The shelf life of butter can vary from weeks to several months, depending on the type of butter and the storage temperature. Unsalted butter has a shorter shelf life than salted butter.

Salt is added to butter as a flavouring, but especially as a preservative, due to the property of salt to inhibit the growth of most yeasts and moulds and some bacteria and therefore to extend the shelf life of butter (1).

The shelf life of unsalted butter is 2 weeks in the refrigerator and 5 months in the freezer, while the shelf life of salted butter is 2 months in the fridge and 6 to 9 months in the freezer (5).

How to properly store butter?

You can store butter in the refrigerator or the freezer. To store butter in the refrigerator, keep the butter protected from moisture and oxygen (1).

To store butter and improve its shelf life, you should store it in the freezer. The results are better when a fast freezing rate is used, to reduce the size of the ice crystals formed and prevent damage to the butter texture (6).

Temperature fluctuations can lead to loss of quality and loss of the emulsion. The exposure of butter to moisture during frozen storage can lead to oxidation due to enzymatic hydrolysis, resulting in the generation of off-odours and off-flavours.

Pack the butter in a moisture-proof package with a good oxygen and moisture barrier and avoid temperature fluctuations during the frozen storage.

Other FAQs about Butter that you may be interested in.

Can butter go bad if left out?

Can you replace vegetable oil with butter?

Can butter be used in place of margarine?


In this article, we answered the question “Can you get sick from eating expired butter?” and discussed how can you get sick from eating expired butter, and how to know if butter is spoiled and hot to to properly store butter.

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Budhkar YA, Bankar SB, Singhal RS. Microbiology of cream and butter. Encyclopedia of food microbiology. 2014;1:728-37.


Adler BB, Beuchat LR. Death of Salmonella, Escherichia coli O157: H7, and Listeria monocytogenes in garlic butter as affected by storage temperature. Journal of food protection. 2002 Dec 1;65(12):1976-80.


Clark S, Costello M, Drake M, Bodyfelt F, editors. The sensory evaluation of dairy products. Springer Science & Business Media; 2009 Jul 30.


Lee CL, Liao HL, Lee WC, Hsu CK, Hsueh FC, Pan JQ, Chu CH, Wei CT, Chen MJ. Standards and labeling of milk fat and spread products in different countries. journal of food and drug analysis. 2018 Apr 1;26(2):469-80.


Evans JA, editor. Frozen food science and technology. Blackwell; 2008.