How long is unopened mayonnaise good for after the expiration date? (3+ factors)
In this article, we will answer the following question: “How long is unopened mayonnaise good for after its expiration date?” and discuss what factors determine the shelf life of unopened mayonnaise, how to correctly store mayonnaise to improve its shelf life and how to know if the mayonnaise has gone bad.
How long is unopened mayonnaise good for after the expiration date?
How long unopened mayonnaise is good after the expiration date is very difficult to predict. Unopened mayonnaise can be safe to eat for many days or months after the expiration date, although the flavour and odour change (2).
According to studies, mayonnaise loses its sensorial properties three months after the expiration date but can be consumed even 6 months past the “best by” date indication (1).
On the other hand, improper storage of unopened mayonnaise can lead to the deterioration of the product before the expiration date. In addition, contaminations during the production process or package defects may occur, resulting in the fast spoilage of mayonnaise (1, 2).
What is the shelf life of mayonnaise?
The approximate shelf life of unopened mayonnaise is, according to recommendations of the United States Department of Agriculture, 3 to 6 months at room temperature. After being opened, the shelf life is 2 months in the fridge (3).
The refrigerated storage of unopened mayonnaise is recommended to reduce the loss of quality during storage, although not mandatory. However, due to the multiple factors that may determine the shelf life of mayonnaise, its storage time may vary (1).
What determines the shelf life of unopened mayonnaise?
The shelf life of unopened mayonnaise may be determined mainly by the following factors (1, 2, 4, 5):
Storage conditions: Exposure to heat and light can drastically reduce the shelf life of mayonnaise, as mayonnaise is composed mainly of lipids that are sensitive to these factors, which cause rapid lipid oxidation.
The ingredients: A study showed that mayonnaise produced with fish oil degrades fast, having a shelf life of about 4 months at 2 °C, because of the nature of the fish lipids, which contain high amounts of polyunsaturated fatty acids.
On the other hand, mayonnaise produced only with vegetable oil, such as sunflower oil and mustard, has a shelf life of 10 months. Mustard contains antioxidants that can retard the lipid oxidation. Similarly, the addition of chemical or natural antioxidants can improve the shelf life of mayonnaise.
The pH: A critical parameter in the production of mayonnaise is the pH value of the product. The addition of acidulants, especially acetic acid in the form of vinegar, is required to inhibit the growth of Salmonella and other hazardous pathogenic microorganisms.
A study showed that a pH value of 4.5 permitted the growth of Salmonella Thyphimurium, while a pH of 3.94 or below could inhibit it.
The package: Mayonnaise can be quickly oxidised once opened and exposed to the environment oxygen, as it is a product very sensitive to oxygen. Therefore, packages with improved oxygen barriers are required to ensure the shelf life of mayonnaise.
How to know if mayonnaise has gone bad?
To know if mayonnaise has gone bad, you should inspect the sensorial properties of mayonnaise, especially the odour. The most common evidence of spoilage in mayonnaise is lipid oxidation, which causes the generation of unpleasant odours, such as rancidity (2, 4).
Lipid oxidation reactions lead to the generation of degrading compounds, such as aldehydes, ketones and alcohols, which characterise off-odours and off-flavours.
Other alterations in mayonnaise indicating spoilage are changes in the colour and consistency (2, 4).
How to store mayonnaise to improve its shelf life?
To store mayonnaise and improve its shelf life, you should consider storing it in the refrigerator, even when the mayonnaise is still unopened (1, 3). Low temperatures of storage are more efficient in preventing lipid oxidation.
It is also possible to store unopened mayonnaise in a cool and dark place away from heat sources and moisture, at temperatures preferentially below 70 °F (20 °C) (6).
Other FAQs about Mayonnaise that you may be interested in.
In this article, we answered the following question: “How long is unopened mayonnaise good for after the expiration date?” and discussed what determines the shelf life of unopened mayonnaise, how to know if mayonnaise has gone bad and how to store mayonnaise to improve its shelf life.
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Karanth S, Feng S, Patra D, Pradhan AK. Linking microbial contamination to food spoilage and food waste: the role of smart packaging, spoilage risk assessments, and date labeling. Frontiers in Microbiology. 2023 Jun 22;14:1198124.
Gorji SG, Smyth HE, Sharma M, Fitzgerald M. Lipid oxidation in mayonnaise and the role of natural antioxidants: A review. Trends in Food Science & Technology. 2016 Oct 1;56:88-102.
Usda.gov. [cited 2023 Aug 15]. Available from: https://www.fsis.usda.gov/shared/data/EN/FoodKeeper-Data.xls
Ghorbani Gorji S, Calingacion M, Smyth HE, Fitzgerald M. Comprehensive profiling of lipid oxidation volatile compounds during storage of mayonnaise. Journal of food science and technology. 2019 Sep 1;56:4076-90.
Keerthirathne TP, Ross K, Fallowfield H, Whiley H. A review of temperature, pH, and other factors that influence the survival of Salmonella in mayonnaise and other raw egg products. Pathogens. 2016 Nov 18;5(4):63.
Uga.edu. [cited 2023 Aug 25]. Available from: https://nchfp.uga.edu/how/store/texas_storage.pdf