In the recent news, the use of formalin by the dealers/transporters/shop owners in the Bangladeshi fish market has raised lot of concern, genuinely so, because Banglee’s ever lasting fondness for fish is well known. Hence the saying Machhe Bhate Bangalee. It’s time we have some perspectives on the issue of formalin use in fish.

First of all ‘what is formalin?’. To most of us it is the smell of the air when you enter any hospital/clinic in BD. Formalin is actually a generic term which describes a solution of 37% formaldehyde gas dissolved in water. [Formaldehyde is produced by adding oxygen to methyl alcohol – the first product in the fermentation process and also a common disinfectant, known as rubbing alcohol in U.S.]

Formalin is used to store biological specimens in laboratories, even preserving human bodies in medical profession known as embalm to prevent the tissues from natural decomposition. Formalin does that by irreversibly binding the protein in the cells with the DNA. But this can lead to deadly effect on living bodies in uncontrolled environment and if used in excess quantity.

Because formalin is readily soluble in water, if consumed it quickly transforms to formic acid (the same thing found in ant bites), which raises the acidity in blood leading to conditions like rapid, shallow breathing, blurred vision or complete blindness, hypothermia, and, in the most severe cases, coma or death. People who accidentally ingest large amount of formalin should seek immediate medical help. Formalin tested on laboratory animals have shown to have carcinogenic (cancer causing) effect. On lighter side formalin can have allergic effect on people. It can cause moderate to severe skin rash and itching.

The use of formalin to prevent fish parasites is not entirely uncommon, but it has to be done in a very controlled way to prevent the toxic effect it might produce. Solutions of formalin for use on fish should contain 10 to 15% methyl alcohol, which inhibits formation of paraformaldehyde a highly toxic compound. In USA only two kinds of commercial products have the approval of Food and Drug Administration (FDA) to be used on selected species of fishes. And even then, the products (not raw formalin) are used to give the fishes a ‘bath’ – meaning apply the formalin product on the fishes for few minutes and then transfer them to a container filled with fresh water to rinse off the excess of formalin.

These controlled products are effective on parasites only, not bacterial or fungal infections. The temperature control is another huge factor when using formalin product (not raw formalin) for fish, because if the temperature is below 40 degree Fahrenheit (5 degree Celcius) then the toxic compound paraformaldehyde will be formed that has deadlier effect than formalin alone. The toxicity is also known to increase at a temperature higher than 75 F (21 C). That is scary because in Bangladesh the temperature is almost always above that level.

It is conceivable that none of the measures discussed above are being taken by the fish dealers. So the Ministry of the food better come up with some regulatory policies on this matter, gaurantee that the fishes sold in the market places do not contain toxic forms of formalin.