Key lime pie is a classic American dessert made with key lime juice, sweetened condensed milk, and egg yolks in a pie crust. When properly stored and prepared, key lime pie can last 3-4 days refrigerated. However, there are some clear signs that indicate your key lime pie has gone bad and should be discarded.
Appearance
The appearance of key lime pie can be the first indicator that it has spoiled. Here are some things to look for:
- Mold growth – Mold will appear as fuzzy spots or patches on the surface of the pie. It can be white, green, black, or blue in color. This is a clear sign to throw the pie away.
- Cracks or dry spots on the surface – If the filling has pulled away from the crust and formed cracks or dry patches, this indicates the pie is old and drying out.
- Watery filling with visible liquid – A watery, thin filling with liquid pooled on top points to the pie being past its prime.
- Custard layer separation – If the custard layer (containing the eggs and condensed milk) has separated from the lime layer, the pie is over the hill.
- Crust is soggy on the bottom – A soggy bottom crust means the filling has wept liquid and indicates the pie is overripe.
Texture
The texture of key lime pie is also important to evaluate for freshness. Here’s what to look out for:
- Grainy, curdled filling – If the custard filling has taken on a grainy, curdled texture, that’s a sign it has spoiled.
- Soft, mushy crust – The crust should be crispy. A crust that has become very soft or mushy points to spoilage.
- Filling is runny – The filling should be thick and sliceable. A runny, thin filling indicates overripeness.
- Cheesy-looking filling – If the filling has taken on a “cheesy” appearance and consistency, it has gone bad.
Smell
Smell is an important sense when determining whether foods have spoiled. With key lime pie, be on the alert for these smells:
- Sour smell – Fresh key lime pie has a pleasant, bright citrus smell. If you detect a strong sour or fermented odor, it’s gone bad.
- Moldy/musty smell – If you pick up any mustiness or mildew-like odors, the pie is inedible.
- Rotten egg smell – This sulfur-like smell indicates the pie has been contaminated by bacteria and should be tossed.
Taste
You should rely on multiple senses, including taste, to determine if a key lime pie has gone bad. Here’s what to look out for:
- Bitter taste – The filling will take on a distinct bitter taste.
- Fizzy texture – Bubbles or fizzing when you eat it indicates fermentation and spoilage.
- Sour taste – An extremely sour flavor points to the pie being overripe.
- Off tastes – Any flavors that seem “off” or rancid are signs you shouldn’t eat the pie.
When in Doubt, Throw it Out!
Trust your senses – if a key lime pie smells, looks, feels or tastes off in any way, don’t take chances. Key lime pie poisoning is rare, but can cause unpleasant symptoms like nausea, vomiting and diarrhea. Don’t risk getting sick over a dessert – when in doubt, throw it out!
How to Store Key Lime Pie Properly
To get the longest shelf life out of your key lime pie and avoid spoilage, proper storage is key. Here are some tips:
- Refrigerate – Key lime pie must be stored in the refrigerator. Keep whole pies refrigerated until ready to slice and serve.
- Use within 3-4 days – For best quality and freshness, plan to eat refrigerated key lime pie within 3-4 days of preparation.
- Avoid temperature fluctuations – Don’t leave pie sitting out at room temperature for long periods of time, as this encourages spoilage.
- Protect from air – Once sliced, cover leftover pie tightly in plastic wrap or aluminum foil to block air exposure and minimize drying out.
Freezing Key Lime Pie
Freezing is a great option for storing key lime pie long-term. Here’s how to do it right:
- Double wrap slices in plastic wrap and aluminum foil before freezing. This prevents freezer burn.
- Freeze whole pies up to 2-3 months.
- Freeze slices for up to 1 month.
- Thaw slices in the refrigerator overnight before serving.
- Let thawed pie come to room temperature before serving for best texture.
How to Tell When Key Lime Juice Has Gone Bad
Since key lime juice is a prime ingredient in key lime pie, it’s important to also know how to tell if it has gone bad. Here are tips:
- Check expiration date – Fresh key lime juice lasts 4-6 months past the printed expiration date when refrigerated.
- Inspect color – Fresh juice should be a slightly cloudy, greenish color. Yellow, brown or murky juice has gone bad.
- Give it a sniff – Rancid, fermented aromas point to spoilage.
- Taste test – An extremely bitter, sour, or unpleasant flavor indicates the juice is over the hill.
- Watch for growth – Mold, yeast bubbles or slimy texture signals spoilage.
For peak freshness, use key lime juice within 2-4 weeks of opening. When refrigerated and tightly sealed, an unopened bottle will stay good for up to a year.
How to Tell When Condensed Milk is Bad
Sweetened condensed milk is another integral ingredient, so you’ll want to know how to determine if it has expired. Here’s what to look for:
- Sour smell or taste – Fresh condensed milk has a mildly sweet scent and flavor. Rancid or sour odors point to spoilage.
- Lumpiness – Smooth, uniform texture indicates freshness. Lumps, clumps or dry film on top are problematic.
- Gas bubbles – Fermentation produces carbonation. Bubbles mean the milk has turned.
- Mold – Any fuzzy growth in or on the milk signals it’s gone bad.
- Color change – Unopened and opened condensed milk should be a light creamy white. Yellow or darker hues indicate spoilage.
Properly stored, unopened condensed milk lasts 6-9 months past the “best by” date. Once opened, it will keep for up to 2 weeks refrigerated.
How to Tell if Eggs Used in Key Lime Pie are Bad
Key lime pie is made with egg yolks, so it’s also helpful to know how to determine if eggs have gone bad before making your pie. Here are some common signs:
- Sunken yolk – In fresh eggs, the yolk should sit up high. A flat or broken yolk means it’s old.
- Cloudy whites – The whites should look clear. Cloudiness indicates aging.
- Pink, brown, green yolk – A natural yellow-orange yolk signals a fresh egg.
- Bad odor – Rotten eggs give off a distinct sulfur smell.
If you’re ever uncertain about an egg’s freshness, crack it open into a bowl before adding to your key lime pie. You’ll be able to inspect it thoroughly that way.
Common Causes of Key Lime Pie Spoilage
Understanding why key lime pie goes bad can help you make it safely and take steps to prevent spoilage. Here are some common causes of key lime pie spoilage:
- Improper refrigeration – Key lime pie needs continuous refrigeration. Leaving it out too long gives bacteria a chance to multiply and spoil the dessert.
- Too much time at room temp – Letting freshly made pie sit out more than 2 hours before refrigerating can encourage food poisoning microbes to grow.
- Old ingredients – Using expired, aging eggs, condensed milk or lime juice in the recipe introduces problematic bacteria.
- Unsanitary conditions – Making the pie on a dirty surface or with unwashed hands can introduce unwanted bacteria.
- Storing after serving – Refrigerating pie after it’s been brought to room temp and served allows bacteria from utensils/plates to migrate into the filling.
How Long Does Key Lime Pie Last in the Fridge?
Under proper refrigeration, key lime pie will maintain best quality for 3-4 days. After that point, you may notice the crust getting soggy, the filling becoming watery, and the bright citrus flavor deteriorating. Many people consume refrigerated key lime pie within 5 days without getting sick – but quality declines. For food safety, it’s best to throw out homemade pie after 5-7 days in the fridge.
Does Store-bought Pie Last Longer?
Store-bought key lime pie generally contains preservatives that prolong its shelf life. Commercially prepared pies in air-tight packaging can last 5-7 days refrigerated from the sell-by date. Check product labeling for any specific use-by/best before dates and storage guidance. Once opened, consume refrigerated store-bought pie within 5 days.
Can You Freeze Key Lime Pie?
Yes, key lime pie can be successfully frozen to enjoy later. Wrap slices tightly in plastic wrap and foil, or freeze whole pies up to 2-3 months. Thaw in the refrigerator before serving to prevent condensation. Let thawed pie come to room temperature before eating for ideal texture. Freeze any slices that were served back to room temperature within 2 hours.
Can You Refrigerate Key Lime Pie Twice?
It’s not recommended to refrigerate key lime pie after it’s been left out at room temperature twice. Bringing the pie out to room temp and back to the fridge twice gives bacteria more chances to multiply. Stick to refrigerating the pie once – either freshly made OR within 2 hours of serving. Refrigerate any uneaten portions promptly.
How Long Does Key Lime Pie Last at Room Temperature?
Room temperature allows bacteria to thrive, so key lime pie shouldn’t sit out too long. Here are some guidelines:
- 2 hours maximum sitting out after baking
- 2 hours max at room temp once served
- 1 hour max if outdoors in hot weather above 90°F (32°C)
After hitting the 2 hour mark sitting out, the pie must be refrigerated or frozen again as soon as possible. Otherwise bacteria may grow to unsafe levels and make the pie potentially hazardous to eat.
Can You Get Sick from Eating Bad Key Lime Pie?
Eating spoiled key lime pie can potentially make you sick, due to harmful bacteria like staphylococcus, salmonella, and E. coli. However, most key lime pie poisoning cases just involve temporary digestive upset. Here are the possible symptoms:
- Nausea
- Vomiting
- Stomach cramps
- Diarrhea
- Fever
- Headache
In healthy adults, symptoms typically resolve on their own in 24-48 hours. But infants, elderly people, pregnant women and those with weakened immune systems are at higher risk of severe illness from food poisoning. Seek medical care if symptoms don’t improve or worsen.
How to Prevent Key Lime Pie from Going Bad
You can minimize the chances of your key lime pie going bad with these food safety practices:
- Use fresh, non-expired ingredients
- Refrigerate pie immediately after baking
- Refrigerate leftovers within 2 hours of serving
- Keep refrigerated at 40°F or below
- Use clean utensils and baking surfaces
- Wash hands thoroughly before preparation
- Keep pie tightly wrapped when stored
- Don’t let pie sit at room temperature over 2 hours
Following proper storage guidelines and food handling hygiene will keep your tasty key lime pie fresher longer.
Frequently Asked Questions
How can you tell at a glance if key lime pie is bad?
Visible mold, cracks in the filling, a watery or separated texture, soggy crust and an “off” color can signal bad pie at a glance. Rely on multiple senses, not just sight, to assess freshness.
What happens if you eat key lime pie that has gone bad?
Eating spoiled key lime pie can cause foodborne illness. Symptoms like nausea, vomiting, diarrhea, fever and cramps may occur within 12-48 hours. In healthy people, it usually resolves without medical treatment. But seek help if symptoms are severe.
Can key lime pie be reheated after refrigeration?
It’s not recommended. Reheating risks the pie filling curdling or separating. Enjoy key lime pie chilled or at room temp instead. Freeze slices to reheat later.
How do you revive an old key lime pie?
There’s no way to safely “revive” a key lime pie that has gone bad. Discard pies with any signs of spoilage. Freezing when fresh is the best way to enjoy older pie.
Does key lime pie need to be refrigerated?
Yes, absolutely. Key lime pie must be stored in the refrigerator to prevent bacterial growth. Keep it refrigerated except when serving, and return to fridge within 2 hours.
