Knowing how to identify fish contaminated with urea will help you choose fresh, safe seafood and avoid products treated with harmful chemicals.

How to Identify Fish Contaminated with Urea

1. Eyes
Fresh fish have clear, bulging eyes with elastic corneas.
Spoiled or urea-treated fish often have sunken eyes that appear cloudy or dull. The cornea may be wrinkled or even damaged.

2. Gills
Fresh fish have bright pink or red gills that are firmly attached, not slimy, and free from foul odors.
In contrast, spoiled fish have grayish gills that are loose, slimy, and emit an unpleasant smell.

3. Scales
Fresh fish scales are shiny, tightly attached to the body, and odorless.
Spoiled fish have dull scales that are easy to peel off and may have a bad smell.

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How to Identify Fish Containing Harmful Chemicals

4. Flesh (Belly Test)
Press the fish flesh gently with your fingertip. Fresh fish flesh is firm and elastic and quickly returns to its original shape.
Fish that is spoiled or treated with urea often has poor elasticity and should not be selected.

5. Mouth and Teeth
Fresh marine fish usually have tightly closed mouths. Spoiled fish tend to have partially open mouths.
For frozen fish stored too long or improperly, teeth may loosen or fall out.

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Health Risks of Urea-Treated Fish

Consuming fish preserved with urea can cause serious health problems:

• Food poisoning:
  Urea can decompose into ammonia, which may cause nausea, vomiting, abdominal pain, and diarrhea.

• Liver and kidney damage:
  Urea is a waste product in the human body. Excess intake through food forces the liver and kidneys to work harder to eliminate it, potentially leading to impaired organ function.

• Accumulation of toxins:
  Long-term consumption of chemically treated food can lead to chronic diseases and may increase the risk of cancer.

• Digestive system disorders:
  Urea can disrupt intestinal function, disturb gut microbiota balance, and reduce the body’s ability to absorb nutrients.

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