The widespread use of formalin, in preservation of fish, fruit and other food items is posing a threat to public health. The chemical used as a solution in water keeps fish fresh and makes fruits like mangoes attractive. This chemical, usually used to stop dead bodies from rotting, is now being used to preserve edible items.
A recent study by Badan Pengawas Obat dan Makanan (BPOM), Indonesia’s department controlling and surveying food and drug, has found that a section of dishonest traders are using formalin widely in preservation of food items, including fish, tofu, and noodles.
Last December (2005), BPOM performed a laboratorium test of 161 samples of sea products (including fish, squid, shrimp, oyster, dried salted fish / squid), tofu, and wet noodles from 6 cities at Lampung, South Sumatra. The test showed 64 samples were found positive containing formalin.
Furthermore, BPOM also performed a simple experiment on the positive samples in attempt to remove the formalin content. These products were washed thoroughly and boiled in water with a temperature of 80°C for 5 to 10 minutes. The formalin level was reduced but not fully removed. So the conclusion, once formalin is added, it can not be removed.
What is formalin?
Formalin is a colourless strong-smelling chemical substance usually used in industry of textiles, plastics, papers, paint, construction, and well known to preserve human corpse. It is derived from formaldehyde gas dissolved in water.
Exposure from its gas or vapor can cause irritation to the eyes, nose and respiratory tract, causing sneezing, sore throat, larynx constriction, bronchitis and pneumonia. Multiple exposures can lead to asthma. It can also affect the skin, causing dermatitis or allergic reaction.
Serious inhalation or ingestion can cause severe pain with inflammation ulceration and necrosis of the mucous membranes, which line almost every internal organ. This may show as symptoms of nausea, vomiting blood, diarrhea with bloody stool, blood from the urine, acidosis, vertigo, and circulation failure, then death. 30mL is suggested the lethal dose of formalin. The limit allowed in air that is still safe for human is less than 2 ppm.
Formalin that was recently found in food, might not give such obvious reactions. However, this substance is known to be a carcinogenic substance, can precipitate cancer. A study showed mice exposed to formalin with concentration of 6 to 15 ppm for 2 years developed squamous-cell carcinoma in the nostril. Some other studies also show formalin will cause kidney, liver, and lung problems.
- Fish. The fish will be stiff, have rubbery meat, hard scales, red gills, clear eyes, doesn’t have the “fishy smell” and no flies flying around.
- Squid. Very rubbery consistency. Unable to break the meat by hand, which you usually could, only can be cut by a knife.
- Other sea products, including dried salty fish. Formalin will make the fish become stiff, whitish and odorless. Even when cooked, i.e. fried, it will still be stiff.
- Tofu. Its consistency is more rubbery than usual, the surface tends to be hard, won’t spoil after 24 hours. Normally after 24 hours, tofu would become slimy, brittle and sour. If it is steamed, submerged in cold water, or kept in the fridge, it may last longer.
- Wet noodles. Has yellowish color, tends to be elastic, with a drug-like odor or ash-like odor when boiled or mixed with hot water.
How to avoid food with formalin?
- Fish, especially sea fish. Press the fish, if it feels tender, it should be free of formalin. Choose fish which still has its fishy smell. It’s best to buy live fish.
- Avoid dried salty fish.
- Tofu. Choose one with smooth surface and consistency. It’s safer to consume egg tofu or water tofu (also known as japanese tofu), though this product can’t last long and is very brittle.
- Wet noodles. Try the less attractive colored ones.