Some frozen fish do pose a higher health risk and should not be consumed frequently or should be consumed with extreme caution. Based on their source, processing, and storage conditions, the following types of frozen fish should be chosen with caution:
Repeatedly thawed "zombie fish"
These fish undergo repeated freezing and thawing during transportation or storage due to breaks in the cold chain, resulting in:
Loose, inelastic flesh that does not spring back after being pressed
Excessive bacterial growth (such as Listeria), increasing the risk of food poisoning
Severe nutrient loss, resulting in a dry, tough texture
Identification tips: The packaging bag is filled with thick frost; the fish surface is whitish, dry, or cracked.
Fish subjected to illegal preservation treatments (such as formaldehyde soaking)
Some vendors use illegal additives such as industrial formaldehyde to extend shelf life:
The fish flesh becomes abnormally firm, and after cooking, it has a rubbery texture.
It has a pungent chemical smell instead of a normal fishy smell.
Long-term consumption may damage the liver and kidneys, and may even pose a cancer risk.
Large carnivorous fish with excessive heavy metals
Deep-sea fish at the top of the food chain easily accumulate heavy metals such as mercury and cadmium:
Tuna, shark, swordfish, bigeye snapper: Mercury content can reach more than 10 times the safe limit. Long-term consumption by pregnant women and children may affect the development of their nervous system. The head and internal organs have even higher concentrations of heavy metals; it is recommended to discard them.
