There is a bag of pistachios at the back of the pantry, and you can’t remember when you bought it. Do pistachios go bad, or do they last forever like some snacks? They do go bad, mostly through rancidity and sometimes mold. Here is what UC, USDA and FDA say about shelf life, storage and spoilage signs.
Do pistachios go bad?
The Short Answer: Yes. UC’s consumer nut guide lists pistachios, in the shell or shelled, at about 1 year in the refrigerator and about 3 years in the freezer. It says nuts keep quality for only a few months at room temperature, and that room temperature makes the oils go rancid sooner. These are quality estimates, not a promise of safety. Dating is for quality, not safety, per USDA. Throw out pistachios with visible mold, because USDA lists nuts among foods to discard when moldy. Rancid nuts are poor quality, and we’d toss them too. A normal look and smell can’t rule out harmful bacteria, per UC. Sealing them and keeping them in the refrigerator or freezer is the best way to keep them fresh, which is our own advice.
For a complete pantry and fridge reference, see our Food Storage Guide. For related nuts, see whether almonds go bad, whether pecans go bad and whether pecans need to be refrigerated.
Pistachios: At a Glance
Pantry (room temperature)
A few months for nuts in general. Kansas State lists 4 months for unopened in-shell nuts and 2 weeks once a package is opened
Refrigerator (40°F or colder)
About 1 year, per UC’s table. NDSU lists 4 to 6 months for opened nuts
Freezer (0°F or colder)
About 3 years in UC’s table, up to 2 years in its general text
In shell vs shelled
Same refrigerator and freezer times in UC’s table
Moldy pistachios
Discard them. USDA lists nuts under “Discard”
Rancid pistachios
UC says rancid nuts are not unsafe, but quality is poor. We’d toss them
“Best by” date
A quality date, not a safety date, per USDA
Best storage
Sealed, cold and dry. Fridge or freezer for long keeping
Key Takeaways
UC’s consumer nut guide (ANR Publication 8406, August 2010) lists pistachios, in-shell or shelled, at 1 year in the refrigerator and 3 years in the freezer. It says nuts keep quality for only a few months at room temperature.
UC says room temperature storage makes nut oils turn rancid sooner and can encourage insect growth, especially in backyard-harvested nuts. It also says rancid nuts are not unsafe, but we’d discard them for quality.
USDA’s mold page lists peanut butter, legumes and nuts under “Discard” when moldy, and says not to sniff a moldy item.
FDA lists pistachios among the foods most susceptible to aflatoxins. It says regularly eating foods with aflatoxins can increase the risk of liver cancer.
UC says refrigeration and freezing do not destroy Salmonella, and that harmful bacteria cannot be determined by sight, smell, taste or texture.
USDA says product dating is for quality, not safety. Sources disagree on how long opened nuts keep at room temper
