How to Tell If Your Preserved Duck Eggs (Century Eggs) Have Gone Bad

How to Tell If Your Preserved Duck Eggs (Century Eggs) Have Gone Bad

Updated May 29, 2025
CanIEatExpired.com Team
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How to Tell If Your Preserved Duck Eggs (Century Eggs) Have Gone Bad

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Preserved duck eggs, commonly known as century eggs, are a popular delicacy in many Asian countries. These unique eggs undergo a preservation process that gives them their distinctive flavor and appearance. However, like any other food product, preserved duck eggs can go bad if not stored properly or if they are past their expiration date. In this blog post, we will discuss how to tell if your preserved duck eggs have gone bad and provide tips on how to store them correctly to ensure food safety. (Preserved duck eggs century eggs)

Understanding Preserved Duck Eggs (Century Eggs)

Preserved duck eggs, also known as century eggs or hundred-year eggs, are eggs that have been preserved in a mixture of clay, ash, salt, quicklime, and rice hulls for several weeks to several months. This preservation process results in a creamy yolk with a gelatinous texture and a dark, translucent egg white. The eggs have a strong, savory flavor with hints of ammonia and sulfur.

Preserved duck eggs are commonly used in various dishes in Asian cuisine, such as congee, salads, and pickled vegetables. They are also enjoyed on their own as a flavorful and unique snack.

Signs That Your Preserved Duck Eggs Have Gone Bad

Preserved duck eggs can spoil if they are not stored properly or if they are past their expiration date. Here are some signs that your preserved duck eggs may have gone bad:

Visual Inspection

  1. Mold Growth: If you see any mold growth on the eggshell or within the preserved egg, it is a clear indication that the egg has spoiled.
  2. Discoloration: If the egg white or yolk has changed color significantly, such as turning green or black, it is a sign of spoilage.
  3. Cracked or Leaking Eggs: Cracks or leaks in the eggshell can allow bacteria to enter the egg, leading to spoilage.

Smell

  1. Foul Odor: If the preserved duck egg emits a foul or rotten smell, it is a strong indication that the egg has gone bad. Trust your sense of smell when determining the freshness of preserved eggs.

Texture

  1. Slimy or Slimy Texture: If the egg white or yolk feels slimy or has a strange texture, it is likely spoiled.

Proper Storage of Preserved Duck Eggs

To ensure the longevity and freshness of your preserved duck eggs, proper storage is essential. Follow these tips to store your preserved duck eggs correctly:

  1. Keep in the Refrigerator: Store preserved duck eggs in the refrigerator to maintain their freshness. The cold temperature helps slow down the growth of bacteria.
  2. Store in an Airtight Container: Place the preserved duck eggs in an airtight container to prevent them from absorbing odors from other foods in the refrigerator.
  3. Avoid Direct Sunlight: Keep the preserved duck eggs away from direct sunlight or heat sources, as exposure to light and heat can cause them to spoil faster.
  4. Check Expiration Date: Always check the expiration date on the packaging of the preserved duck eggs and consume them before the date indicated.
  5. Rotate Stock: If you have multiple preserved duck eggs, use the oldest ones first to ensure freshness.

Conclusion

Preserved duck eggs, or century eggs, are a unique and flavorful ingredient in many Asian dishes. By understanding the signs of spoilage and following proper storage practices, you can enjoy these delicacies safely. Remember to inspect the eggs visually, use your sense of smell, and check for any changes in texture to determine if the preserved duck eggs have gone bad. Proper storage in the refrigerator, in an airtight container, away from sunlight, and checking the expiration date are crucial steps in maintaining the freshness of preserved duck eggs. Enjoy these delicacies responsibly and savor the unique taste they offer in your culinary creations. (Preserved duck eggs century eggs)

Authoritative Food Safety References

These agencies and university labs inform every tip and health precaution we publish.

USDAOfficial guidance

USDA FoodKeeper – Cold Storage Guidelines

Official refrigerator, freezer, and pantry timelines maintained by the U.S. Department of Agriculture.

Visit USDA FoodKeeper
FDAOfficial guidance

FDA Produce Safety Rule & Grower Guidance

Field-to-fridge handling practices that prevent contamination of fruits, vegetables, and leafy greens.

Visit FDA Produce Safety
CDCOfficial guidance

CDC Foodborne Illness Prevention Hub

Surveillance-backed guidance on pathogens, symptoms, and steps to reduce foodborne illness risk.

Visit CDC Food Safety
ResearchUniversity research

Penn State Extension – Home Food Preservation & Safety

Peer-reviewed extension bulletins on safe canning, chilling, and reheating practices.

Visit Penn State Extension
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Our articles are created using a combination of AI assistance and human review. All food safety information is based on USDA guidelines and credible sources. Learn more about our review process here.