Spots on Olives: Are They Dangerous or Safe To Eat?

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Ever found yourself peering at spots on olives, curious about those tiny specks or larger blotches? These spots can come in a whole spectrum of colors – from white to black, brown, and even blue-green – and each carries a story of its own.

Spots on olives can be caused by various factors such as natural oxidation, fermentation, bacterial or fungal growth, or can be a by-product of the processing method.

The safety of eating spotted olives depends mainly on the nature of the spots. Some spots caused by natural processes or harmless microorganisms are safe, while others indicating harmful mold or bacterial growth are unsafe.

In this article, we’re going on a deep dive into the causes of these spots on olives, exploring whether they’re safe and how to ensure they are always ready for your next meal.

spots on olives are they dangerous or safe to eat 1

I. Causes of Spots on Olives

Let’s start exploring various factors contributing to the formation of different colored spots on olives, be they black, brown, white, green, or blue-green. Here is a brief overview of spots on olives’ common causes and potential risks.

Spot ColorCommon CausesPotential Risks
Fungal infection
Yeast fermentation
Mostly harmless but could affect taste and quality. Fungal infections can be a concern if the specific fungus is harmful.
Excess water
Fungal infection
Could be harmless, but spots resulting from fungal infection or improper fermentation process may pose risks.
White or White SubstanceCristalized salt or minerals
Yeast fermentation
Lactic acid bacteria fermentation
Generally safe. The spots are mainly caused by the crystallization of natural compounds.
Green or Blue-GreenLack of brine,
Mold, specifically Penicillium
Bacterial infection
Green spots are usually safe. Blue-green spots due to mold or bacteria might affect taste and texture and, in rare cases, could pose a safety risk.
Table 1. Types of spots on olives common causes and potential risks

Of course, this table should be adjusted to suit your specific findings and research. Always

1. Black Spots on Olives

The black spots you see on the surface of your olives are usually the result of an oxidation process. Oxidation can occur when the olives are exposed to air during processing or storage, leading to black spots.

olives in a jar black spotted
Tiny black spots on olives can often result from natural causes such as oxidation or yeast fermentation and typically do not pose any health risks.

Sometimes these black spots may also indicate the growth of certain fungi, such as Aspergillus. While the thought of fungus might not be appetizing, these types are typically harmless and often occur when the olives aren’t adequately dried or are stored in high-humidity conditions. However, there can be instances where these fungi might not be as friendly, potentially producing harmful toxins, so it’s essential to be vigilant.

Finally, the black spots can also result from a phenomenon known as “flyspeck”. It’s a condition caused by a specific kind of yeast that tends to grow on the fruit’s surface, creating distinct black specks. Again, these are generally harmless but might alter the aesthetics of your olives.

black spots on olives
Black spots on olives can sometimes result from yeast fermentation, which may occur during the olive curing process.

2. Brown Spots on Olives

The brown spots on olives are typically a result of oxidation processes, similar to the black spots. When olives are exposed to air during the processing stage or storage, this can lead to these intriguing brown spots. It’s all part of the chemistry of our favorite fruit!

Specific fermentation processes might also lead to the formation of brown spots. So, if you’re seeing these spots, it could indicate that your olives have undergone some natural fermentation. While this might affect the look of your olives, it generally doesn’t pose any health risks.

We should also note that these brown spots could be due to excess water in the olives. This is especially true if your olives have been in storage for a while and haven’t been adequately drained.

Of course, while most brown spots are harmless, we should keep a keen eye on our olives. In rare cases, they could be signs of more severe issues like fungal growth, similar to black spots.

brown spots on olives
Brown spots on olives are often a product of oxidation or fermentation processes that typically don’t pose any health concerns.

3. White Spots or Substance on Olives

Opening a jar of olives only to see little white spots or a cloudy white substance can seem alarming initially, but it’s usually relatively harmless and ordinary.

So, what are we really seeing here? In most cases, what you’re seeing is crystallized salt or minerals that were initially dissolved in the brine. The shift in temperature during storage or transit can cause these compounds to crystallize or precipitate out, making themselves seen in the form of a white substance. Think of it like the sugar in your iced tea – when it gets cold, the sugar can settle out and become visible.

Also, don’t forget that white spots can result from harmless yeast growth during fermentation or even be due to water or oil droplets trapped within the jar. So, don’t fret over the appearance of these white freckles; they’re typically a natural part of the olive’s life journey.

But there’s another factor at play – lactic acid bacteria fermentation. It’s a standard step in olive preparation that can contribute to the appearance of white spots or a cloudy brine. During this process, sugars in the olive are converted into lactic acid, contributing to the preservation and that tangy olive flavor we love. Byproducts from this fermentation can become trapped and visible as tiny white spots. Likewise, the interaction between lactic acid and brine elements can cause a cloudy appearance.

In conclusion, white spots or a milky-looking brine are often just signs of natural processes in the life of your olives.

white spots on olives
White spots on your olives in a jar result from yeast fermentation, a natural and harmless process that doesn’t affect their safety for consumption.

4. Green or Blue-Green Spots on Olives

In fresh, raw olives, these can be natural color variations or slight skin imperfections, which are perfectly normal. For jarred or canned olives, it’s often a small area where the brine didn’t fully penetrate, causing a slightly different coloration. But it’s usually harmless and won’t affect your olive’s taste or safety.

olives in a brine
Olives may develop spots if they are not fully submerged in brine during storage, as this exposure to air can lead to discoloration and potential bacterial or fungal growth.

However, if these spots look more blue-green, they could indicate the growth of Penicillium mold. This can happen when olives aren’t properly dried or if they’re stored in conditions with high humidity. While this mold is generally not harmful, it could affect the olive’s flavor and texture.

One more potential culprit for green or blue-green spots is pseudomonas bacteria. This bacteria can grow on olives if stored improperly or the brine solution isn’t acidic enough. These bacteria can create green or blue-green spots, but more importantly, they can make your olives smell and taste off.

green spots on olives
Green spots on olives may be areas where the olive hasn’t been thoroughly penetrated by the brine having no effect on the taste or safety of the olives.

II. Are Spotted Olives Dangerous?

It’s important to keep in mind that not all spots on olives are a sign of danger. There are a number of factors that can cause these spots to appear, ranging from harmless natural processes to potential health concerns. The key is to understand what these spots signify and to be able to distinguish between normal variations and possible warning signs.

For instance, black or brown spots on your olives are often the result of oxidation or fermentation, and in some cases due to harmless fungal growth or the presence of excess water. These are typically safe and should not stop you from relishing your olive delicacies.

Similarly, white substances or specks on your olives are usually just crystallized salt, minerals from the brine, or are a result of yeast or lactic acid bacteria fermentation. Once again, these are generally safe and have no cause for alarm.

But not all spots or changes in color are harmless. Green or blue-green spots can indicate Penicillium mold or bacterial infection. These are clear signals that your olives might have been compromised and may pose a risk if consumed. In such cases, it’s essential to discard these olives to steer clear of potential health risks, as food poisoning.

This table can help you quickly understand which spots are harmless and which require caution:

Spot ColorReasonsRisk LevelNotes
BlackOxidationLowMay affect taste and quality but is generally safe.
BlackFungal infectionMediumCould cause some deterioration in quality and taste.
BlackFungal infection (Aspergillus)HighCould produce harmful toxins, best to discard.
BlackYeast fermentationLowTypically harmless, although it can affect taste and quality.
BrownOxidationLowUsually harmless but can affect taste and quality.
BrownFermentationMediumCould be harmless, but improper fermentation may pose risks.
BrownExcess waterMediumMay promote fungal growth and affect quality.
BrownFungal infectionMediumCould cause some deterioration in quality and taste.
BrownFungal infection (Aspergillus)HighCould produce harmful toxins, best to discard.
White/White SubstanceCrystallized salt or mineralsLowUsually safe; the white substance is the result of natural compounds crystallizing.
White/White SubstanceYeast fermentationLowTypically harmless, although it can affect taste and quality.
White/White SubstanceLactic acid bacteria fermentationLowGenerally safe; it’s a natural part of the fermentation process.
GreenLack of brineLowTypically safe; green spots are usually a result of natural color variations or areas not penetrated by the brine.
Green/Blue-GreenMold (specifically Penicillium)MediumMight affect taste and texture. In rare cases, could pose a safety risk.
Green/Blue-GreenBacterial infectionHighCould pose a risk to health, especially if the bacteria are harmful.
Green/Blue-GreenMold (Aspergillus)HighCould produce harmful toxins, best to discard.
Table 2. Comparative risk analysis about spots on olives

What About Mold on Olives?

Spots on olives aren’t always innocent. In fact, if you see green, blue-green, or other unusual colored spots on your olives, caution is warranted. These spots might indicate the presence of mold.

Mold growth in food is not a minor concern. It poses potential health risks, including food poisoning, allergic reactions, and in certain circumstances, respiratory problems.

Molds, a type of fungi, find warm and damp conditions favorable for their growth. Given the chance, they can infest various foods, including olives, becoming a significant health hazard. Some molds even produce toxic substances called mycotoxins. Eating food contaminated with these toxins can cause health issues.

Adding to the complexity, certain types of mold such as Aspergillus can lead to similar concerns. They often present as black or brown spots on olives and while they may not always be harmful, certain strains of this mold can produce harmful toxins. This means that it’s not only the green or blue-green spots that warrant caution.

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III. Can You Still Eat Spotted Olives?

Firstly, you’ve got to remember not all spots are created equal. Some spots, particularly those on raw olives, are completely harmless and natural. They can result from the olive’s natural maturation process or caused by environmental conditions during growth. On the other hand, spots on your olives in the jar can often be due to harmless minerals or salts from the brine solution.

However, if you notice mold-like spots or a slimy texture, it’s best to err on the side of caution. Molds, particularly harmful ones like Aspergillus and Penicillium, can produce mycotoxins which can pose health risks if ingested. So, if you’re in doubt, it’s better to discard these olives.

The ‘white stuff’ on olives in jars is another matter. Often, it’s a harmless yeast known as Candida boidinii, and although it can impact the olives’ taste and texture, it usually doesn’t pose health threats.

So, the bottom line is, yes, you can still eat spotted olives, as long as you’re sure the spots are harmless.  Inspect the olives carefully. If the spots result from natural pigmentation or salt crystallization, they should be safe to eat. However, if the spots are fuzzy, accompanied by an unusual odor or a change in texture, it’s best to discard those olives.

So, to summarize, yes, you can still eat spotted olives if you can confidently identify the spots as harmless, such as due to natural pigmentation, salt crystallization, or benign fermentation processes. However, if the spots are fuzzy, have an unusual odor, or have altered the olives’ texture, it’s best to play it safe and discard them.

olives with spots gained naturally
Olives with spots gained naturally, such as through oxidation, fermentation, or environmental variations during growth, are generally safe to eat and pose no health risks.

How to Clean White Spots Prior Eating Olives?

In situations where the white spots on your olives are indeed caused by harmless factors like crystallized salt or minerals, you can still consume these olives.

However, if you find the spots visually unappealing or if they slightly alter the texture of the olive, you can opt to rinse the olives under cold water before consumption. A gentle scrub can also help dislodge any crystallized particles on the surface.

Keep in mind that this can lead to a mild reduction in the saltiness or the flavor intensity of the olives. As always, if the spots are not easily removed, or if changes in smell or texture accompany them, it’s safer to discard the olives.

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IV. How to Store Olives Correctly to Avoid Spots and Mold

The first thing you need to remember is the importance of a tight seal. Air is an uninvited guest that can lead to quicker spoilage and promote the growth of mold. So, let’s keep that jar shut tight when not in use!

Next, we should think about temperature and light. A cool, dark place is an olive’s best friend, with the fridge being the top choice. But, remember not to lose them behind that leftover lasagna or last week’s takeout!

Now, for those of you who’ve got olives in a brine, here’s my tip: let the olives take a long, relaxing soak. The brine acts as a natural preservative, keeping your olives in tip-top shape for longer.

Also, once that jar is opened, aim to enjoy your olives within two weeks. After this, you might start seeing those pesky spots or unwanted mold.

Last, but certainly not least, be vigilant! Always inspect your olives before you eat them. If you spot any signs of spoilage or something looks off, don’t risk it—better safe than sorry.

Check our olives storage guidelines in this table:

Storage FactorGuideline
TemperatureOlives should be stored at cool room temperatures, ideally between 55-60°F (13-16°C). Avoid placing them near heat sources.
Light ConditionsKeep your olives in a dark place, as exposure to light can degrade their quality. Avoid clear glass jars for long-term storage.
ContainerUse an airtight container for storing olives. This prevents moisture loss and entry of bacteria or molds.
Olive LiquidMake sure olives are fully submerged in their brine or oil. This helps maintain their freshness and prevents mold growth.
Shelf-lifeMost jarred olives can last for up to two years unopened. Once opened, consume within a couple of weeks and always smell for off-odors before eating.
Table 3. Best practices of olives storage.

Note: proper storage can significantly extend the life of your olives and ensure they remain safe to eat.

how to store olives to avoid spots and mold
To avoid spoilage, olives should be stored in a cool, dark place in an airtight container, fully submerged in their brine, ensuring they remain fresh and free from harmful bacterial or fungal growth.

When to Dispose of Olives

If you’ve noticed a drastic change in the smell, color, or texture of your olives, it’s a significant red flag. Trust me, your nose and eyes are often the best tools to determine whether the olives have overstayed their welcome. A peculiar smell, especially one that’s quite strong and unpleasant, usually suggests that something isn’t right.

Let’s also talk about mold. If you see any mold formation, whether it’s fuzzy or slimy, of any color – black, green, or white, it’s a clear sign that your olives need to go. Remember, consuming moldy olives can lead to food poisoning symptoms like nausea and vomiting, so it’s better to be safe than sorry.

Finally, don’t forget to consider the storage duration. If the olives have been sitting in your pantry or fridge for an unusually long time, beyond their sell-by date, it might be time to dispose of them. It’s not worth the risk to consume old, potentially spoiled olives.

Just remember, when in doubt, throw it out! That’s always been my golden rule when it comes to handling and consuming olives. Next up, let’s talk about how to dispose of olives responsibly and safely.

Check our step by step disposal guidelines on spoiled olives:

1Identify the SpoilageFirst and foremost, confirm that your olives are indeed spoiled. Look for spots, mold, or an off smell.
2Isolate the OlivesTo prevent cross-contamination, isolate the jar of spoiled olives from your other food items.
3Dispose of the OlivesTake your olives and throw them into the compost or trash. Be sure to wash your hands afterwards to avoid spreading bacteria or mold.
4Clean the JarIf you plan to reuse the jar, clean it thoroughly. Use hot soapy water and scrub well to remove any leftover mold or bacteria.
5Monitor Your Other OlivesKeep a close eye on your other olives, particularly if they were stored near the spoiled jar. If you spot any signs of spoilage, it’s best to err on the side of caution and dispose of those too.
Table 4. Steps to dispose of spoiled olives responsibly.

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Frequently Asked Questions

Can you get sick from eating moldy olives?

Yes, consuming moldy olives can potentially lead to foodborne illnesses. Symptoms can include nausea, vomiting, and abdominal pain. More serious health complications can arise if the mold is a producer of mycotoxins, such as Aspergillus.

How can I prevent spots or mold on my olives?

Storing your olives correctly is the best way to prevent spots or mold. This includes keeping them in a cool, dark place, fully submerged in their brine or oil, and using an airtight container for storage.

What can be done about these white spots on my olives?

If the white spots are yeast, it’s a natural part of the fermentation process and is harmless. However, if it’s mold, the olives should be discarded. The key here is identification. If you’re uncertain, it’s safer to dispose of the olives.

How long are olives good for?

When properly stored in a cool, dark place and submerged in their brine or oil within an airtight container, olives can last up to two years. However, once opened, olives should be consumed within a few weeks for optimal taste and safety. Always check for any signs of spoilage such as spots, off smells, or changes in texture before consuming.


Let’s take a moment to review the main points and come back to our central inquiry: ‘Spots on olives: are they dangerous or safe to eat?’:

  1. We’ve learned that various factors, including fermentation processes, oxidation, and bacterial or fungal growth can cause spots on olives. These spots can appear as black, brown, or white patches on the olives or in the jar.
  2. Mold on olives is another common issue, manifesting as white, green, black, or blue discolorations. Mold can develop due to improper storage conditions or if the olives have been compromised.
  3. The safety of consuming spotted or moldy olives depends on the nature of the spots or mold. Some spots are harmless, while others can indicate the presence of harmful bacteria or fungi. As such, discarding any olives with questionable spots or signs of mold is always best.
  4. We’ve also discussed the importance of storage, and disposal to prevent the formation of spots and mold. By choosing high-quality olives, storing them properly, and disposing of them responsibly when they’ve spoiled, we can ensure a safe and enjoyable olive-eating experience.

In conclusion, while some spots on olives are benign, others can indicate spoilage or the presence of mold. The key is to be cautious and discerning. If you’re ever in doubt about the safety of your olives, it’s better to be safe than sorry—dispose of them and opt for a fresh jar.

I believe this article guides you in understanding the nature of these spots, the potential risks involved, and how to safely handle olives. Stay informed, stay vigilant, and you’ll be able to enjoy your olives without worry.

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