How to know if olives are spoiled?

In this article, we will discuss how to know if olives are spoiled. This article will also cover the health consequences of eating spoiled olives and how to store them properly to increase their shelf life. 

How to know if olives are spoiled?

To determine if olives are spoiled, you can look for several signs:

• Visual indicators: Check for rust, bulges, or discoloration on the olives. Spoiled olives may have visible rust or bulges, and their color may be slightly off.

• Smell test: Give the olives a sniff. Fresh olives typically have a salty yet fresh smell. Spoiled olives, on the other hand, may have a distinct and unpleasant odor. If the olives smell off or moldy, it’s a sign they have gone bad.

You should never eat spoiled olives, especially if they are contaminated with molds or other harmful microorganisms as they can produce very dangerous toxins that can make you very sick (1). 

• Texture changes: Observe any changes in the texture of the olives. Black olives might turn lighter in color, while green olives can become mushy, dull green, or develop spots. These changes in texture indicate spoilage.

• Taste check: If you’re still uncertain about the olives’ freshness, taste a few olives. Spoiled olives will have a noticeably bad taste compared to their normal salty and creamy flavor. If the taste is off or unpleasant, it’s a clear indication that the olives have gone bad.

After opening a jar of olives, you may notice a white layer at the top of the brine solution. This layer is harmless and does not mean the olives are spoiled. You can safely consume the olives without worrying if you see this white layer.

It is very important to note that olives sold in a salt solution have a longer shelf life, thanks to the preservative nature of the solution. However, it is still advisable to check the expiration date or best-by date on the jar or pouch of olives to ensure they are within their freshness period. 

Always follow any storage instructions provided by the manufacturer, as they might specify the recommended duration for consuming the olives after opening. 

Is pale color a bad sign?

No, don’t worry if your olives start getting paler in the brine solution. It is because of the salt solution that causes the color to lighten over time. But if you see spots or a moldy green color then that is not a good sign. 

Remember molds produce dangerous mycotoxins that can make you very sick (1-2). You should never eat spoiled olives!

Can you get sick from eating spoiled olives?

Yes, eating spoiled olives can pose significant health risks due to the presence of harmful pathogens. Consuming olives that have gone bad can lead to food poisoning, which is caused by various bacteria commonly associated with spoiled food (3-4). 

Pathogens such as Salmonella can result in symptoms like nausea, vomiting, abdominal cramps, diarrhea, fever, and headaches (3-4). Escherichia coli strains like E. coli O157:H7 can cause severe illness with symptoms including severe abdominal cramps, bloody diarrhea, vomiting, and, in some cases, kidney failure (3-4). 

Listeria monocytogenes, another bacterium found in spoiled olives, can cause listeriosis (3-4), leading to fever, muscle aches, nausea, diarrhea, and potentially more severe symptoms like headaches, stiff neck, confusion, and convulsions, particularly in vulnerable populations (5). 

Additionally, mold growth on olives can produce mycotoxins, which are toxic substances (1). Ingesting these mycotoxins can result in allergic reactions, respiratory problems, gastrointestinal issues, and potential long-term health effects (6).

In rare cases, spoiled olives can also be contaminated with the bacterium Clostridium botulinum, which produces a toxin causing botulism (7).  

Symptoms of botulism include difficulty swallowing and speaking, facial weakness, blurred or double vision, drooping eyelids, muscle weakness, and, in severe cases, paralysis (8). Botulism is a life-threatening condition that requires immediate medical attention. 

You should know that the severity of symptoms can vary from person to person. It might be influenced by factors such as the individual’s overall health, the specific harmful germ consumed, the amount of contamination in the olives, and the quantity eaten.

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

If you have consumed spoiled olives and start having symptoms of food poisoning (9), it is very important to keep a close eye on your symptoms and seek medical help if the symptoms become severe or last for a long time. 

You should also stay hydrated to prevent dehydration in case you experience vomiting or diarrhea as recommended (10). 

Remember that you should always practice good hygiene and get rid of any remaining spoiled olives to avoid further problems for you and others. 

What is the shelf life of olives?

The shelf life of olives can vary depending on various factors, including the type of olives and how they are stored (11). Here are some general guidelines for the shelf life of different types of olives:

• Fresh Olives: Fresh olives, which are unprocessed and typically not cured, have a relatively short shelf life. They are best consumed within a few days or weeks after being harvested.

• Canned or Jarred Olives: Olives that come in cans or jars, often preserved in brine or oil, have a longer shelf life. Sealed and unopened cans or jars of olives can typically be stored for several months or even up to a year or more, depending on the specific product and the manufacturer’s instructions. 

It is important that you always check the expiration date or best-by date on the packaging for accurate information.

• Cured Olives: Cured olives are processed to reduce their natural bitterness and improve their flavor. Common curing methods include brine curing, salt curing, or lye curing. 

The shelf life of cured olives can vary depending on factors such as the curing method, the presence of preservatives, and how they are stored. Properly stored, cured olives can generally last for several months or even up to a year.

You should know that the shelf life of your olives can vary depending on the specific product, processing methods, and storage conditions. 

Thus, it is best that you always refer to the manufacturer’s instructions or the best-by date indicated on the packaging for the most accurate information on the shelf life of  your olives. 

How to properly handle olives to avoid spoilage?

If you want to keep the olives fresh for a longer time, keep the jar unopened in a cool and dry place such as the pantry where the temperature is cold and dry. After opening the jar and using olives, make sure that you place the jar in the fridge.

Opened olive cans should not be put in the fridge, instead the olives along with the brine solution should be shifted to an airtight jar that will protect the olives from going bad. Make sure that the olives are completely submerged in the liquid once they are opened. 

You might have noticed how the lid pops when you open it, this is because of the trapped air inside. The lid is very tightly closed and it helps the olives stay fresh for a longer time. To increase the shelf life of olives, you should also do the same after you open the lid each time.

Conclusion:

In this article, we discussed how to know if olives are spoiled. This article also covered the health consequences of eating spoiled olives and how to store them properly to increase their shelf life. 

References:

1.    Gourama H, Bullerman LB. Mycotoxin production by molds isolated from ‘Greek-style’ black olives. Int J Food Microbiol [Internet]. 1988 Feb 1 [cited 2023 Jun 7];6(1):81–90. Available from: https://www.sciencedirect.com/science/article/abs/pii/0168160588900876 

2.    Dantigny P, Conika M, Fontana A, Schorr-Galindo S. Mycotoxins during Consumer Food Storage. Mycotoxins Food Beverages Innov Adv Part I [Internet]. 2021 Jun 10 [cited 2023 May 31];51–68. Available from: https://www.taylorfrancis.com/chapters/edit/10.1201/9781003035817-3/mycotoxins-consumer-food-storage-philippe-dantigny-monika-conika-angélique-fontana-sabine-schorr-galindo 

3.    Argyri AA, Lyra E, Panagou EZ, Tassou CC. Fate of Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes during storage of fermented green table olives in brine. Food Microbiol [Internet]. 2013 Oct 1 [cited 2023 Jun 7];36(1):1–6. Available from: https://www.sciencedirect.com/science/article/abs/pii/S074000201300066X 

4.    Grounta A, Nychas GJE, Panagou EZ. Survival of food-borne pathogens on natural black table olives after post-processing contamination. Int J Food Microbiol [Internet]. 2013 Feb 15 [cited 2023 Jun 7];161(3):197–202. Available from: https://www.sciencedirect.com/science/article/abs/pii/S0168160512006587 

5.    Lennard LB. Food microbiology and food poisoning. In: Food & Nutrition [Internet]. Taylor & francis Gr…. Routledge; 2020 [cited 2023 May 30]. p. 132–54. Available from: https://www.taylorfrancis.com/chapters/edit/10.4324/9781003115663-11/food-microbiology-food-poisoning-louise-lennard 

6.    Patel P, Komorowski AS, Mack DP. An allergist’s approach to food poisoning. Ann Allergy, Asthma Immunol [Internet]. 2023 Apr 1 [cited 2023 May 5];130(4):444–51. Available from: https://pubmed.ncbi.nlm.nih.gov/36334721/ 

7.    Jalava K, Selby K, Pihlajasaari A, Kolho E, Dahlsten E, Forss N, et al. Two cases of food-borne botulism in Finland caused by conserved olives, October 2011. Eurosurveillance [Internet]. 2011 Dec 8 [cited 2023 Jun 7];16(49):20034. Available from: https://www.eurosurveillance.org/content/10.2807/ese.16.49.20034-en?crawler=true 

8.    Ting PT, Freiman A. The story of Clostridium botulinum: from food poisoning to Botox. Clin Med (Northfield Il) [Internet]. 2004 May 5 [cited 2023 May 3];4(3):258. Available from: https://pubmed.ncbi.nlm.nih.gov/15244362/ 

9.    Milaciu M V, Ciumărnean L, Orășan OH, Para I, Alexescu T, Negrean V. Semiology of food poisoning. Int J Bioflux Soc [Internet]. 2015 [cited 2023 May 10];8(2):108–13. Available from: http://hvm.bioflux.com.ro/docs/2015.108-113.pdf 

10.  McRobert GR. THE TREATMENT OF BACTERIAL FOOD POISONING. Br Med J [Internet]. 1934 Aug 8 [cited 2023 May 10];2(3841):304. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2445530/ 

11.  García-García P, López-López A, Garrido-Fernández A. Study of the shelf life of ripe olives using an accelerated test approach. J Food Eng [Internet]. 2008 Feb 1 [cited 2023 Jun 7];84(4):569–75. Available from: https://www.sciencedirect.com/science/article/abs/pii/S0260877407003615