Is out of date peanut butter safe to eat? (risks)
In this article, we will discuss in which cases expired peanut butter is no longer safe to eat, the risks of eating expired peanut butter and how to identify spoiled peanut butter.
Peanut butter has a long shelf life due to its low moisture content, On the other hand, the lipids in the peanut butter undergo oxidative processes which can reduce the shelf life of peanut butter if not properly stored.
Is out of date peanut butter safe to eat?
Yes, out of date peanut butter may be safe to eat, unless there are signs of spoilage in the product (2).
When kept unopened and correctly stored, that is, in a cool and dark place and protected from moisture and light, peanut butter can be consumed after its expiration date, especially in the case of commercial products, which contain stabilisers or other additives (1, 3).
Can peanut butter go bad?
Yes, peanut butter can go bad. Peanut butter is rich in unsaturated fatty acids which oxidise with time.
When exposed to oxygen, heat, moisture and light these fatty acids react and generate oxidative products, such as peroxides, aldehydes and ketones, which characterise rancidity (1, 3).
What is the shelf life of peanut butter?
The shelf life of peanut butter depends on many factors, such as the composition of the product, the addition of preservatives, the storage conditions and the type of packaging (1, 3, 4).
Homemade peanut butter has a shorter shelf life due to the lack of stabilisers added to commercial products.
A study showed that the temperature affected significantly the stability of natural homemade peanut butter and storing at low temperatures favoured the shelf life (1).
The shelf life of peanut butter is the following (5):
- 6 to 24 months when kept unopened
- 2 to 3 months after opening if stored at room temperature
- 6 months after opening if stored in the refrigerator
What are the risks of eating out-of-date peanut butter?
The risks of eating out-of-date peanut butter are long-term, and related to the consumption of oxidised lipids (6).
When unsaturated fatty acids oxidise, they generate reactive oxygen species (ROS), which are free radicals, very reactive molecules.
These ROS can interfere with the cell metabolism in many cellular metabolic pathways, leading to damage.
The negative health consequences of these phenomena in the long term may include inflammatory diseases, cancer and heart disease.
In addition, peanut butter that has been stored for a long time can increase in moisture, favouring the development of microorganisms, including pathogenic bacteria, such as Salmonella (3).
Many food outbreaks were reported due to the consumption of contaminated peanut butter.
How to identify spoiled peanut butter?
Spoiled peanut butter can be identified especially by its odour and flavour (1, 3, 4).
As the fatty acids in peanut butter oxidise, they generate off-odours, which are very intense. Off-flavours related to bitterness and rancidity are also identified.
Another characteristic of spoiled peanut butter is the oil separation, which is visible on the surface of the product.
Changes in the colour may also occur, due to Maillard reactions, which cause darkening.
How to increase the shelf life of peanut butter?
To increase the shelf life of peanut butter, you should store it in the refrigerator even when still unopened (1, 3).
After opening, protect the peanut butter from moisture and store it in the refrigerator.
If stored at room temperature, keep the peanut butter away from heat and light and in a dry place.
Do not store peanut butter in metal packaging, as metal can accelerate the oxidative processes.
In this article, we discussed how to identify spoiled peanut butter, the risks of consuming spoiled peanut butter and how to increase the shelf life of peanut butter. If properly stored, peanut butter has a long shelf life and can be safely consumed for a long time.
Was this helpful?
Mohd Rozalli NH, Chin NL, Yusof YA, Mahyudin N. Quality changes of stabilizer-free natural peanut butter during storage. Journal of food science and technology. 2016 Jan;53:694-702.
Usda.gov. [cited 2023 Oct 17]. Available from: https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/food-product-dating
Sithole TR, Ma Y-X, Qin Z, Wang X-D, Liu H-M. Peanut Butter Food Safety Concerns—Prevalence, Mitigation and Control of Salmonella spp., and Aflatoxins in Peanut Butter. Foods [Internet] 2022;11(13):1874. Available from: http://dx.doi.org/10.3390/foods11131874
Shakerardekani A, Karim R, Ghazali HM, Chin NL. Textural, rheological and sensory properties and oxidative stability of nut spreads—a review. International journal of molecular sciences. 2013 Feb 20;14(2):4223-41.
Usda.gov. [cited 2023 Oct 17]. Available from: https://www.fsis.usda.gov/shared/data/EN/FoodKeeper-Data.xls
Vieira, Samantha A., Guodong Zhang, and Eric A. Decker. Biological implications of lipid oxidation products. J. Am. Oil Chem.’ Soc., 2017, 94, 339-351.