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What Happens if You Eat Expired Pistachios

What Happens if You Eat Expired Pistachios?

Pistachios are a popular and delicious snack that many of us love to eat. Their unique flavor and satisfying crunch make them hard to resist. But what happens if you eat expired pistachios? Are they still safe to eat or should you throw them out? In this article, we’ll explore everything you need to know about eating expired pistachios.

Do Pistachios Go Bad?

Pistachios can go bad due to their oil and fat content. The high amounts of fat and oil make them more prone to rancidity and spoilage compared to other nuts and seeds. Like other tree nuts, pistachios have a relatively short shelf life compared to dried fruits.

Proper storage is key to extending the shelf life of pistachios. With the right storage conditions, pistachios can stay fresh for 5-6 months at room temperature. Refrigerating or freezing pistachios can extend their shelf life to about one year. But regardless of storage, pistachios will eventually go bad.

You can often determine if pistachios have gone bad based on their appearance and smell. Fresh pistachios should have a mild nutty aroma. Discoloration, visible mold, a rancid smell, or shriveled texture are clear signs pistachios have spoiled. Paying attention to these signs of freshness and spoilage will help you avoid eating expired nuts.

What Happens If You Eat Expired Pistachios?

Now we come to the key question – what actually happens if you eat pistachios past their prime? Here is what you need to know:

  • Upset stomach – Rancid and moldy pistachios can cause nausea, stomach pain, diarrhea. The high fat content makes effects worse.
  • Allergic reaction – Some people may experience tingling or itching in mouth or throat after eating expired nuts if they have a nut allergy.
  • Mold exposure – Eating moldy pistachios increases risk of mold spore inhalation which can cause respiratory issues. People with lung conditions are especially at risk.
  • Food poisoning – If pistachios contain mycotoxins from mold growth, they can cause food poisoning symptoms like vomiting and fever. Severity depends on amount consumed.
  • Nutritional loss – Over time, the vitamin and antioxidant content of pistachios declines so nutritional value is lower.

The good news is eating a few stale or slightly old pistachios is unlikely to make you seriously ill. However, moderate consumption of truly rancid, moldy or insect-infested nuts could result in foodborne illness. When in doubt, remember “If it’s brown or has a frown, throw it down!

How Do I Know if My Pistachios Are Bad?

There are several clear signs that indicate pistachios have gone bad and should be discarded:

  • Mold growth – Any mold or fuzzy growth on the pistachio shells or nutmeats means they should be thrown out. Mold spores can spread to other nuts and contaminate them.
  • Dark brown color – The nutmeats inside healthy pistachios should be yellow, green or ivory in color. Dark brown or odd colored nutmeat suggests the pistachios are too old.
  • Bugs – Presence of bugs inside the pistachio bag or jar is a giveaway the nuts have gone bad. Discard immediately.
  • Withered texture – Fresh pistachios should be firm and crisp. Shriveled, wrinkled, or dried out pistachios are well past their prime.
  • Expired date – Check the best by or sell by date on the label. However, remember this is only a general guideline for peak freshness. Pistachios may still be ok to eat for a short time after.

Trust your eyes, nose and taste buds to determine if your pistachios are still good or not. Rancid pistachios will have an unpleasant taste and smell.

How to Tell if Pistachios Are Rancid

A common sign of pistachios gone bad is a rancid smell or taste. Rancid pistachios have high levels of free fatty acids that degrade the quality and give an unpleasant flavor.

Here are some tips for identifying rancid pistachios:

  • Smell – Rancid pistachios will have a distinctive sour, unpleasant smell similar to old crayons or nail polish.
  • Taste test – If you are unsure about the smell, taste one pistachio. Rancid nuts will taste bitter and leave a lingering unpleasant aftertaste.
  • Appearance – Rancid pistachio nutmeats may look darker in color or shriveled up. The shells may also appear stained or wet looking from leaking oils.
  • Texture – Pistachios normally have a crisp bite. Rancid nuts will taste mealy in texture.

If you detect any rancid notes from the smell or taste, it’s best to discard the entire batch. The rancid oil can quickly spread and spoil any remaining good nuts. Don’t take a chance with rancid pistachios.

How Long Do Pistachios Stay Good For?

The shelf life of pistachios depends largely on how they are stored. Proper storage is key to maintaining freshness and preventing premature spoilage. Here is a guide to how long pistachios stay good for under different storage conditions:

  • Room temperature – 5 to 6 months. Keep in a cool, dark pantry away from heat and sun.
  • Refrigerator – About 1 year. Store in an airtight container in the back of the fridge.
  • Freezer – Up to 1 year. Place in air-tight freezer bag or container.
  • Pantry storage – Up to 6 weeks. After opening, transfer pistachios to an airtight container.

No matter where you store them, keep pistachios in a cool environment away from moisture and light. An unopened package will last longer than pistachios stored loose in a jar or container. Watch for any signs of spoilage as pistachios get older.

Should Pistachios Be Refrigerated?

Refrigeration can help extend the shelf life of pistachios, especially if you live in a hot or humid environment. The cold air preserves the nuts by slowing down the oil oxidation process. Storing in the refrigerator can make pistachios last for about 1 year.

Here are some tips for properly storing pistachios in the fridge:

  • Place pistachios in an airtight glass or plastic container. This prevents them from absorbing fridge odors.
  • Limit exposure to moisture by keeping container tightly sealed.
  • Store nuts in the back of the refrigerator where temperature is most consistent.
  • Keep an eye on use-by date. Refrigeration can’t prevent pistachios from eventually going bad.
  • For freezer storage up to 1 year, transfer shelled pistachios to freezer bags or containers. Leave unshelled nuts in their original packaging.

While refrigeration can extend shelf life, pistachios stored at room temperature in a cool pantry will still last for 5-6 months. Feel free to refrigerate for extra freshness as needed.

How to Buy Pistachios

Buying high-quality fresh pistachios is the first step to ensuring they last as long as possible. Here are some shopping tips:

  • Check sell-by and best-by dates and choose packages with the farthest dates.
  • Avoid packages with signs of moisture or stains which indicate older or damaged nuts.
  • Inspect for visible mold, damage, or insects. This signals poor storage conditions.
  • Choose pistachios still in their shells, which tend to stay fresher than shelled nuts.
  • Opt for unsalted and unroasted pistachios. Seasonings and roasting shorten shelf life.
  • Buy only amount you plan to eat within a few months to avoid waste.
  • Once open, transfer pistachios to an airtight jar or container for storage.

Following proper storage methods and buying high-quality unprocessed pistachios can help you enjoy fresh pistachios for many months. Discard any that show signs of mold, rancid smell or taste, bugs, or other spoilage.


Pistachios are a tasty snack, but like other nuts they eventually go bad. Store pistachios properly in a cool, dark place and avoid humidity to get the longest shelf life. Refrigerate pistachios in airtight containers to keep them fresh for up to one year. Inspect nuts periodically and discard any with mold, odd colors, rancid smells, or wrinkled texture. Eating truly spoiled pistachios, especially moldy ones, carries a risk of food poisoning and allergic reaction.

But the bottom line is: trust your eyes and nose. If pistachios pass the sight and smell test, they should be safe to enjoy in moderation past their expiration date. Just be aware of any stomach upsets and discard them at the first sign of a problem. With proper storage and handling, you can safely enjoy delicious pistachios for many months.

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