Fish is an extremely perishable food item and requires preservation for future consumption. The Bangladeshi farming community is known for its rich heritage of sun drying fish that consumers can savour in the off-season as shutki, a traditional culinary delicacy.
But when it comes to health and hygiene, the traditional way of processing dried fish is grossly compromised on many counts. Fish are dried under the sun, exposed to germs and pollution in the environment. Besides, harmful chemical pesticides are often applied to protect the dried fish from flies, beetles and other insects.
Thanks to the Bangladesh Council of Scientific and Industrial Research (BCSIR, popularly known as Science Lab), a hygienic means of drying fish is being made available for people in the dried fish industry.
Reaz Ahmad/Dhaka TribuneCurrently, 20% of Bangladesh's 0.6 million tons of marine fresh catch are preserved as dried fish for later consumption (mostly domestic consumption) and also for exports, fetching only $2.5 million a year – much less than its potential.
If the companies involved in dried fish production start employing commercial fish dryers, BCSIR scientists hope Bangladesh's name can be seen in the list of dried fish export toppers such as Vietnam, Ecuador and India.
The major problem of sun drying is efficiency and the quality of the final product remains at the mercy of nature. In improper sun drying, the dried product suffers from many disadvantages. Under unfavourable operational parameters (rain, overcast weather, lack of sunlight, etc) it takes several days to complete sun drying, which affects the quality of the final product; the possibility of contamination with dust or sand, or infestation with insects is high. A big concern is application of insecticides at a high rate, which some farmers resort to in order to avoid insect infestation, eventually damaging the quality of the product and causing harm to human health.
Md Rezaul Karim heads BCSIR's Institute of Technology Transfer and Innovation (ITTI). He told Dhaka Tribune that the technology that BCSIR has been promoting is cost-effective, hygienic, and will give dried fish producers the edge over traditional competitors in the export market.
Reaz Ahmad/Dhaka TribuneIn the dehydration process, as drying is carried out under a controlled environment, most of the disadvantages faced in sun drying can be overcome and the desired quality of the final product can be maintained. Dehydrated products have a comparatively longer shelf-life than sun dried products.
Dryers are devices used to dry fish in a controlled environment. A variety of dryers are used for drying fish (cabinet dryer, kiln dryer, tunnel dryer, spray dryer, solar tent dryer, etc).
At ITTI, BCSIR scientists also demonstrated the application of UV exposure light that all dryer-dried fish pass through, thereby substantially reducing the risk of any pathogens or germs. In traditional sun drying, producers tend to apply lots of salt for long-duration preservation and weight advantage, but again it is not healthy for human consumption.
Asked about the outcome of such technology promotion so far, Rezaul Karim said some Chittagong-based dried fish producers have already shown keen interest in producing dried fish in a hygienic way and one of them has started installing the dryer and UV light facilities.
It requires Tk17 lakh for setting up a modern dryer facility, but the return is worth the investment. One can produce 30 tons of dried fish a year. BCSIR scientists say that if Bangladeshi dried fish producers go for dryers instead of sun drying, their dried fish production cost will be halved as it requires less manpower, no insecticides and it is quicker and hygienic.
Fish drying is carried out in some selected coastal areas and inland depressions of Bangladesh where modern preservation facilities and good infrastructure for transportation are absent. Some important spots are Dublar Char in the Sundarbans, St Martin's Island, Rangabali, Sonadia Island, Moheshkhali, Cox's Bazar, Kuakata, lbrahimpur of Sunamganj, and Joshomantapur of Jamalganj.
The important marine and freshwater species that are dried are Loitya (Harpodon neherius), Chhuri (Lepturacanthus savala), Punti (Puntius sarana, P. stigma), chapila (Gadusia chapra), Lakhua (Polynemus indicus), Rupchanda (Pampus chinensis), and shrimps (Metapenaeus species and Penaeus species).