Can you eat black fungus (wood ear mushroom) the next day after it has been soaked overnight?

Aug 29, 2025 Source: Cainiu Health

Dr. Yu Yongchao

Introduction

Under normal circumstances, whether木耳 (wood ear mushrooms) can be consumed overnight mainly depends on the storage conditions and the condition of the mushrooms themselves. When soaking wood ear mushrooms, use clean cold or warm water, avoid soaking them at room temperature for extended periods, and promptly wash and cook them after soaking. Any leftover cooked wood ear mushrooms should be sealed and refrigerated, and stored for no more than 24 hours. Carefully inspect the condition of the mushrooms before consumption, and discard them immediately if their safety is in doubt.

Generally speaking, whether木耳 (wood ear mushrooms) can be consumed overnight depends mainly on the storage conditions and the state of the mushrooms. The specific analysis is as follows:

If the mushrooms have been soaked and promptly sealed in a clean container, refrigerated, and show no signs of becoming sticky, mold spots, have no unpleasant odor, and feel firm and elastic when touched, they can generally be consumed after being thoroughly heated. Low-temperature refrigeration can inhibit bacterial growth, and as long as the storage process is hygienic and there are no signs of spoilage, consumption typically does not affect health.

If the mushrooms have been soaked and left at room temperature for a long time or were not sealed properly during refrigeration leading to cross-contamination, and after overnight storage they become sticky, soft, rotten, have a sour or rotten smell, or show mold spots on the surface, then they should not be consumed. These mushrooms are prone to滋生椰酵假单胞菌 (Pseudomonas cocovenenans), which may produce heat-resistant toxins that cannot be eliminated even after thorough heating. Consumption may cause severe gastrointestinal discomfort or even endanger health.

When soaking mushrooms, use clean cold or warm water and avoid soaking them at room temperature for extended periods. Promptly wash and cook after soaking. Any leftover cooked mushrooms should be sealed and refrigerated, and stored for no longer than 24 hours. Carefully check the condition of the mushrooms before consumption; if unsure about their safety, discard them directly and do not take risks. If discomfort occurs after consumption, stop eating immediately and seek medical attention.

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How long can black fungus be soaked before it's no longer safe to eat?

Under normal circumstances, the duration for soaking black fungus before it becomes unsuitable for consumption should be determined based on the soaking temperature. In a room temperature environment of 20°C to 30°C, soaking should not exceed 4 hours; in high-temperature environments above 30°C, soaking should be limited to within 2 hours; when soaked in a refrigerator under cold storage, the time can be extended to about 12 hours. Black fungus soaked beyond the corresponding time limits is not recommended for consumption.

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Are dried black fungus that have been stored for several years still edible?

Under normal circumstances, whether aged dried black fungus (wood ear) that has been stored for several years is still edible depends on the specific storage conditions and the current state of the fungus. When purchasing dried black fungus, choose according to actual needs and avoid buying and stockpiling excessive amounts at once. During storage, ensure it is kept in a sealed container or sealed bag in a dry and well-ventilated area, away from water sources and heat sources. Carefully inspect the condition of the dried fungus before consumption, and use sufficient warm water for soaking.

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What to Eat to Lower Blood Pressure

Under normal circumstances, patients with hypertension can choose to eat foods such as celery, bananas, oats, black fungus (wood ear), and garlic. They may also take antihypertensive medications such as amlodipine maleate tablets, metoprolol tartrate tablets, hydrochlorothiazide tablets, nifedipine controlled-release tablets, and captopril tablets as directed by a physician. In addition to controlling blood pressure through dietary adjustments, maintaining a healthy lifestyle can also help achieve the goal of lowering blood pressure.