Cooking food with chlorinated tap water and adding iodized salt can make food toxic which adversely affects health, claims new study. A team of researchers from the Hong Kong University has identified some unknown compounds formed after chlorinated water reacts with the iodized salt at a high temperature. These dangerous compounds were unknown to the scientists, maybe that’s why someone didn’t point towards the adverse effects of cooking with chlorinated tap water.
Since, water can get infected with several microorganisms, thus it is disinfected before we use it for drinking purpose or for cooking. Disinfecting or water treatment is done by two ways — Chlorination and Chloramination. Water chlorination is the process of adding chlorine (Cl2) or hypochlorite to water. This method is used to kill certain bacteria and other microbes in tap water as chlorine is highly toxic. In particular, chlorination is used to prevent the spread of waterborne diseases such as cholera, dysentery, typhoid etc. While, Cholramination is the process of adding chloramines to water. Chloramines are derivatives of ammonia by substitution of one, two or three hydrogen atoms with chlorine atoms. Both the process changes the chemical structure of water.
According to study, both chlorine and chloramines present in the disinfected tap water can react with the iodine present in the iodised salt to form an acid named hypoiodous acid (an inorganic compound with the chemical formula HIO). Hypoiodous acid is a weak acid and it does not cause any harm on its own, but it can react with the food and other organic compounds present in it to form iodinated disinfection byproducts (I-DBPs). Now, I-DBPs molecules were unknown yet and they are new to researchers. To discover the properties of I-DBPs, researchers created these molecules in the lab and tested for their toxicity.
The authors were shocked to see that our daily routine cooking generates these unknown toxic compounds. With the help of technology and chemistry techniques, researchers have successfully identified 14 completely new molecules, of which structures of nine molecules have been identified. Further testing revealed that some molecules were less toxic while some molecules were about 50-200 times more toxic.
Xiangru Zhang, corresponding author of the paper and Associate Professor at the Hong Kong University of Science and Technology said that mixture of chlorinated tap water and iodized table salt generates toxic compounds that are completely new to scientists. He further added that only way to prevent generation of such molecules is by cooking food at low temperatures.
The study appeared in the journal Water Research.
First Published on: Nov 27, 2015, 05:36 AM