UKM News Official Portal

By Kuah Guan Oo 

BANGI, 24, August 2010 – Have you ever wondered why your favourite fish, prawns or squids are so fresh in the markets or restaurants?  

Sure, science may have made tremendous progress to keep your seafood ever so fresh like refrigeration and instant chilling that could raise the profit margins of importers, distributors and retaillers without nary a care to the consumer’s health. 

One of the most repulsive and hazardous method that has been used to keep seafood fresh is formaldehyde solution, commonly called embalming fluid that is employed to preserve dead bodies. 

More than disgusting and revolting that the thought of eating embalmed seafood can invoke in you, is the little known fact that formaldehyde is toxic, allergenic and carcinogenic! 

For this reason, a group of scientists of Universiti Kebangsaan Malaysia (UKM) led by Prof Dr Lee Yook Heng has developed a biosensor for a cheap, simple and quick test to see whether your seafood contained dangerous levels of formaldehyde, an organic compound that is widely available in the market and widely used in the industries. 

Prof Dr Lee said no formaldehyde is allowed under the nation’s Food Act and it is not listed as a preservative. However, some seafood on their own do produce a low level of the organic compound naturally.  

He said the Ministry of Health has till now collected samples of seafood imports for laboratory tests for formaldehyde but the results take times to know. Furthermore, laboratory tests, though precise in results, would require expensive machineries and trained personnel.  

For this reason, the UKM team of researchers of whom five are professors had embarked on the search for biosensors since 2001 that are based on enzymes, DNA, anti-bodies and whole cells, and that can be made available in the market as a test kit for a few ringgit. 

One such biosensor is made up of enzymes that can mainly react with formaldehyde.  

To be packaged as a mini device and portable, it uses stacked biosensing film technology and screen-printed electrodes for rapid detection of the hazardous chemical of which “we do not know how serious the problem is in our food chain.” 

Prof Lee said UKM had patented the invention and they are still in the process of bringing the test kits to the market to be used by seafood traders, health officers and even the consumers.  

Another biosensor developed by the UKM scientists, Prof Lee and Prof Dr Musa Ahmad, is a kit to test for ammonia in water.  Called “Electrochemical and Optical sensors for Ammonium Detection”, Prof Dr Lee said it could be useful to those who are concerned or involved with the question of clean and safe potable water for human consumption. 

Excrement or domestic wastewater and leakage from garbage dumps are the common contaminants of rivers from which water companies draw their raw water for treatment before piping it to the consumers. 

“Ammonia is toxic to aquatic life, especially fish, although it is not so toxic to human,” he said.  

But what makes it dangerous to human is when the water treatment plants use chlorine to treat the high level of ammonia and the reactions produce a series of hazardous chemicals that are detrimental to health.  

The water treatment plants have to constantly test the raw river water for ammonia and if it is too high, like the case of 1995 when the El Nino caused river water level to drop too low, they would have to shut down the plants. 

Prof Dr Lee said the biosensors for ammonium they had developed are aimed for users such as water treatment companies.  

Made up of enzymes and coloured chemicals to detect the level of ammonium in water in two minutes or so, he said a private company had signed up with them to produce and market the product. 

 “The company is now talking to the users to see how the test kits can be made more user-friendly,” he said. 

Both the sensor products for formaldehyde and ammonium have won awards internationally in INPEX, USA and Exhibition in Brussels, Belgium and nationally in research exhibitions such as ITEX and Asian biotechnology.