Can vegetable oil go bad?
The contents of this article are fact-based except otherwise stated within the article.
Author bio
Dr Tayse has extensive experience in studying the chemical composition and stability of foods, as well as their bioactive properties.
Dr Tayse da Silveira´s Highlights:
- Lecturer at the State University of São Paulo (Unesp), Brazil, for Food Engineering students
- Post-doctorate in Food Science, with a one-year training period at Cirad – France.
- PhD in Food Science, with a one-year scholarship at the University of Reading/United Kingdom.
- Bachelor of Food Engineering at the Federal University of Pará, Brazil.
“Food Science is exciting because it touches our lives in such personal and intimate ways. Understanding food systems and gaining knowledge of how to manipulate them, helps society evolve as a whole” – Dr Tayse da Silveira.
Professional experience:
In her doctorate at the University of Campinas, Dr Tayse studied the effect of emergent preservation techniques, such as high-pressure processing, on the chemical and microbial properties of foods.
After completing her doctorate, Tayse da Silveira worked as a postdoctoral fellow in the Pharmaceutical Science Department at the University of São Paulo (USP), with a one-year training at CIRAD, Montpellier, France.
During this period, Dr Tayse worked on the development and evaluation of innovative antioxidant molecules for the preservation of fatty food products.
Dr Tayse also taught in public and private universities in Brazil for Nutrition, Food Engineering, and Enology students, always on food science and food technology-related subjects, including microbiology, milk technology, and wine-making technology.
She has also been involved in a number of studies evaluating the chemical composition and bioactive properties of food products, with emphasis on the development of analytical techniques to achieve that.
Currently, Dr Tayse works at the Centro de Investigação de Montanha (MRC), Portugal. She continues to work on the study of the chemical composition of foods, with a focus on identifying and isolating molecules with potential for application as food ingredients.
In her research, she targets molecules able to provide health and nutritional improvement, and antioxidant and antimicrobial properties (natural food additives).
She regularly publishes in high-impact, specialized scientific journals in her field, and feels encouraged to expand her knowledge domain by doing new scientific partnerships.
Education
- 2017 – PhD in Food Science at the University of Campinas Brazil, with a one-year training period at the University of Reading/United Kingdom.
- 2013 – Master’s Degree in Food Science at the University of Campinas, Brazil.
- 2011 – Bachelor of Food Engineering at the Federal University of Pará, Brazil.
Relevant Published work
- Roschel GG, da Silveira TFF, Cajaíba LM, Ferrari RA, Castro IA. Combination of natural strategies to improve the oxidative stability of echium seed oil. Journal of Food Science. 2021;86(2):411-9.
- de Moraes MR, da Silveira TFF, Coutinho JP, Souza DS, Duarte MCT, Duarte RT, et al. Bioactivity of atemoya fruits and by-products. Food Bioscience. 2021;41:101036.
- Ferreira da Silveira TF, Laguerre M, Bourlieu-Lacanal C, Lecomte J, Durand E, Figueroa-Espinoza MC, et al. Impact of surfactant concentration and antioxidant mode of incorporation on the oxidative stability of oil-in-water nanoemulsions. LWT. 2021;141:110892.
- da Silveira TFF, Cajaíba LM, Valentin L, Baréa B, Villeneuve P, Castro IA. Effect of sinapic acid ester derivatives on the oxidative stability of omega-3 fatty acids rich oil-in-water emulsions. Food Chemistry. 2020;309:125586.
- Roschel GG, da Silveira TFF, Cajaiba LM, Castro IA. Combination of Hydrophilic or Lipophilic Natural Compounds to Improve the Oxidative Stability of Flaxseed Oil. European Journal of Lipid Science and Technology. 2019;121(5):1800459.
- da Silveira TFF, Cristianini M, Kuhnle GG, Ribeiro AB, Filho JT, Godoy HT. Anthocyanins, non-anthocyanin phenolics, tocopherols and antioxidant capacity of açaí juice (Euterpe oleracea) as affected by high pressure processing and thermal pasteurization. Innovative Food Science & Emerging Technologies. 2019;55:88-96.
- da Silveira TFF, de Souza TCL, Carvalho AV, Ribeiro AB, Kuhnle GGC, Godoy HT. White açaí juice (Euterpe oleracea): Phenolic composition by LC-ESI-MS/MS, antioxidant capacity and inhibition effect on the formation of colorectal cancer related compounds. Journal of Functional Foods. 2017;36:215-23.
You can view some of Dr Tayse´s work below and links to her professional profile:
ResearchGate: https://www.researchgate.net/profile/Tayse-Ferreira?ev=hdr_xprf
Scopus: https://www.scopus.com/authid/detail.uri?authorId=55901968900
Google Scholar: https://scholar.google.com/citations?user=l4zi0d8AAAAJ&hl=pt-PT
Linkedin: https://www.linkedin.com/in/tayse-ferreira-a2311947/
Reviewer bio
Dr Tayse has extensive experience in studying the chemical composition and stability of foods, as well as their bioactive properties.
Dr Tayse da Silveira´s Highlights:
- Lecturer at the State University of São Paulo (Unesp), Brazil, for Food Engineering students
- Post-doctorate in Food Science, with a one-year training period at Cirad – France.
- PhD in Food Science, with a one-year scholarship at the University of Reading/United Kingdom.
- Bachelor of Food Engineering at the Federal University of Pará, Brazil.
“Food Science is exciting because it touches our lives in such personal and intimate ways. Understanding food systems and gaining knowledge of how to manipulate them, helps society evolve as a whole” – Dr Tayse da Silveira.
Professional experience:
In her doctorate at the University of Campinas, Dr Tayse studied the effect of emergent preservation techniques, such as high-pressure processing, on the chemical and microbial properties of foods.
After completing her doctorate, Tayse da Silveira worked as a postdoctoral fellow in the Pharmaceutical Science Department at the University of São Paulo (USP), with a one-year training at CIRAD, Montpellier, France.
During this period, Dr Tayse worked on the development and evaluation of innovative antioxidant molecules for the preservation of fatty food products.
Dr Tayse also taught in public and private universities in Brazil for Nutrition, Food Engineering, and Enology students, always on food science and food technology-related subjects, including microbiology, milk technology, and wine-making technology.
She has also been involved in a number of studies evaluating the chemical composition and bioactive properties of food products, with emphasis on the development of analytical techniques to achieve that.
Currently, Dr Tayse works at the Centro de Investigação de Montanha (MRC), Portugal. She continues to work on the study of the chemical composition of foods, with a focus on identifying and isolating molecules with potential for application as food ingredients.
In her research, she targets molecules able to provide health and nutritional improvement, and antioxidant and antimicrobial properties (natural food additives).
She regularly publishes in high-impact, specialized scientific journals in her field, and feels encouraged to expand her knowledge domain by doing new scientific partnerships.
Education
- 2017 – PhD in Food Science at the University of Campinas Brazil, with a one-year training period at the University of Reading/United Kingdom.
- 2013 – Master’s Degree in Food Science at the University of Campinas, Brazil.
- 2011 – Bachelor of Food Engineering at the Federal University of Pará, Brazil.
Relevant Published work
- Roschel GG, da Silveira TFF, Cajaíba LM, Ferrari RA, Castro IA. Combination of natural strategies to improve the oxidative stability of echium seed oil. Journal of Food Science. 2021;86(2):411-9.
- de Moraes MR, da Silveira TFF, Coutinho JP, Souza DS, Duarte MCT, Duarte RT, et al. Bioactivity of atemoya fruits and by-products. Food Bioscience. 2021;41:101036.
- Ferreira da Silveira TF, Laguerre M, Bourlieu-Lacanal C, Lecomte J, Durand E, Figueroa-Espinoza MC, et al. Impact of surfactant concentration and antioxidant mode of incorporation on the oxidative stability of oil-in-water nanoemulsions. LWT. 2021;141:110892.
- da Silveira TFF, Cajaíba LM, Valentin L, Baréa B, Villeneuve P, Castro IA. Effect of sinapic acid ester derivatives on the oxidative stability of omega-3 fatty acids rich oil-in-water emulsions. Food Chemistry. 2020;309:125586.
- Roschel GG, da Silveira TFF, Cajaiba LM, Castro IA. Combination of Hydrophilic or Lipophilic Natural Compounds to Improve the Oxidative Stability of Flaxseed Oil. European Journal of Lipid Science and Technology. 2019;121(5):1800459.
- da Silveira TFF, Cristianini M, Kuhnle GG, Ribeiro AB, Filho JT, Godoy HT. Anthocyanins, non-anthocyanin phenolics, tocopherols and antioxidant capacity of açaí juice (Euterpe oleracea) as affected by high pressure processing and thermal pasteurization. Innovative Food Science & Emerging Technologies. 2019;55:88-96.
- da Silveira TFF, de Souza TCL, Carvalho AV, Ribeiro AB, Kuhnle GGC, Godoy HT. White açaí juice (Euterpe oleracea): Phenolic composition by LC-ESI-MS/MS, antioxidant capacity and inhibition effect on the formation of colorectal cancer related compounds. Journal of Functional Foods. 2017;36:215-23.
You can view some of Dr Tayse´s work below and links to her professional profile:
ResearchGate: https://www.researchgate.net/profile/Tayse-Ferreira?ev=hdr_xprf
Scopus: https://www.scopus.com/authid/detail.uri?authorId=55901968900
Google Scholar: https://scholar.google.com/citations?user=l4zi0d8AAAAJ&hl=pt-PT
Linkedin: https://www.linkedin.com/in/tayse-ferreira-a2311947/
In this brief article, we are going to answer the question “can vegetable oil go bad?” by providing answers related to the shelf life of vegetable oil, how long it lasts, how to identify stable vegetable oil, and how to store it correctly.
Can vegetable oil go bad?
Yes, vegetable oil can go bad. Oils are nothing more than fat. Chemically, fat in food is mostly formed of fatty acids glued together to form triglycerides.
You have probably heard about triglycerides because they are also present in your blood, and knowing their level is part of that long list of exams during your annual health check-up.
Actually, every fat (the one in red meat, in butter, in porc fat) is primarily made of triglycerides. But triglycerides in vegetable oils are majorly constituted of a special type of fatty acids, the ones that are highly prone to reactions with air (oxidation).
When vegetable oils undergo oxidation, a chain of complex chemical reactions takes place whose main final results are the appearance of off-flavors (rancidity), nutrient losses, and even toxic compounds [1].
How long does vegetable oil last?
An unopened bottle of vegetable oil lasts for six months to one year, according to manufacturers. But this limit date may vary among countries.
When you open a vegetable oil bottle, the shelf life will depend on the handling practices, but as a rule of thumb, it is reduced. The reason is that when you open a bottle of vegetable oil, it gets exposed to air, promoting oxidation.
Even though the quality does not deteriorate immediately, it happens over time because so far, fat oxidation cannot be avoided, just delayed.
But if you stock the oil bottle fastened, safe from excessive heat and light incidence, it can last the whole shelf life period indicated on the label without any significant sign of rancidity.
How to tell if your vegetable oil has gone bad?
Smelling is the best way to know if a vegetable oil has gone bad. Oxidation is easily recognized as rancidity. For this reason, usually, it is not necessary to taste it, just sniff it.
You can also observe the oil color and consistency. Most oils come in clear bottles, so when having look at it, the oil should be translucid.
Turbidity and viscous consistency indicate extensive oxidation and oil like that should be immediately discarded.
All vegetable oils come with a best-before date. This date helps you judge the quality of the oil and it is usually not a determining factor when it comes to the safety of the vegetable oil.
Can you get sick from eating rancid vegetable oil?
No, you do not necessarily get sick from eating rancid vegetable oil. Pathogenic microorganisms (those causing foodborne diseases) cannot grow in oils. It will mostly just taste unpalatable which will make you want to throw it away.
If you feel like you have consumed rancid vegetable oil, it is not a cause for concern and you will not see any immediate side effects.
But in long term, it is not safe continuously ingest oxidized vegetable oil. This is because oxidized fat and oxidized fat-derived compounds are toxic to the human body and may cause or worsen certain types of pathologies.
A number of studies have described the adverse implications of oxidized fat in the human body [1, 2, 3].
What are the health hazards of consuming rancid vegetable oil?
The long-term health hazards of consuming rancid vegetable oil are cellular damage. Previous research showed that rancid vegetable oil contains free radicals, which are highly reactive molecules capable of harming cell membranes, proteins, and DNA [1].
Free radicals are involved in numerous pathological states including several age-related neurodegenerative diseases, such as Alzheimer’s [3].
In addition to free radicals, oxidized oils can also contain toxic compounds derived from the extensive transformation of fatty acids due to oxidation reactions.
According to studies, some of these compounds can be pro-carcinogenic and alter cell functions [2,3].
So the best way to avoid these health hazards is not to consume oils that you perceived as oxidized. You should also store vegetable oils correctly to minimize oxidation, and consequently, the formation of undesirable toxic compounds.
What does affect the shelf life of vegetal oils?
Heat, light, and oxygen are the main factors that affect the shelf life of vegetable oils because they are critical parameters that catalyze oxidation reactions.
This means that vegetable oils exposed to direct sunlight incidence, heat, and air will oxidize much faster than oils kept sealed and safe in a pantry [4].
For example, frying accelerates oil oxidation [4]. With repeated frying cycles, oxidation-derived compounds accumulate in frying oils up to a level that becomes unpalatable and dangerous to health, according to research [4].
How to properly store vegetable oils?
Vegetable oils should be stored in a cool, dry, and dark place, away from the stove because of the heat.
If stored correctly, vegetable oils can last the whole best-before date and a bit more, as long as it still owns proper taste, color, and smell characteristics. Just be mindful and if you have doubts it is best to throw them away.
What to do with vegetable oils that have gone bad?
Follow these tips if you do not know how to proceed with bad vegetable oils:
- Never throw the oil in the sink! Place the oil in a container with a lid — a PET bottle, for example. Look for the nearest collection point.
- If your city does not have a collection point, place the bottle with oil next to the garbage to be collected.
These actions reduce the risks of soil and water resource contamination.
- You can deliver it to experts in making homemade soap. As Francischi [5] explains, it is possible to make soap from cooking oils, but it takes caustic soda, which is very corrosive.
Thus, it is more advisable to give vegetable oil to professionals or take lessons with experts on how to do it before making your soap.
Conclusion
In this brief guide, we discussed the query “can vegetable oil go bad?” by providing answers related to the shelf life of vegetable oil, how long it lasts, how to identify stable vegetable oil, and how to store it correctly.
If you have any comments or questions please let us know.
Citations
1. Vieira SA, Zhang G, Decker EA. Biological Implications of Lipid Oxidation Products. Journal of the American Oil Chemists’ Society. 2017;94(3):339-51.
2. Di Domenico F, Tramutola A, Butterfield DA. Role of 4-hydroxy-2-nonenal (HNE) in the pathogenesis of alzheimer disease and other selected age-related neurodegenerative disorders. Free Radical Biology and Medicine. 2017;111:253-61
3. Zarkovic K, Jakovcevic A, Zarkovic N. Contribution of the HNE-immunohistochemistry to modern pathological concepts of major human diseases. Free Radical Biology and Medicine. 2017;111:110-26.
4. Seppanen CM, Saari Csallany A. Formation of 4-hydroxynonenal, a toxic aldehyde, in soybean oil at frying temperature. Journal of the American Oil Chemists’ Society. 2002;79(10):1033-8.
5. Transforming waste into soap. Available on: https://www.nature.com/articles/d41586-022-01817-6
