In a survey conducted last month, civic officials found the presence of E. coli bateria in 870 of the 948 ice samples collected from bars, restaurants and roadside food and juice stalls.
The BMC will request the Food and Drug Administration to inspect factories that supply ice and take action against them, if required.
In May, the BMC initiated the special drive as a precautionary measure before monsoon when contaminated water causes several health issues. BMC's head of epidemiology Dr Minnie Khetrapal said the tests were carried out throughout the month. "The findings have surprised us. The ice samples were collected from sugarcane juice centres, vendors selling pani puri, golas and a few were from restaurants and bars. The samples were tested thrice to confirm the high levels of contamination," she added.
Interestingly, tap water collected from households did not show high contamination. "Of the 3,317 tap water samples that were tested from households, only 1% had E. coli, while water samples collected from hawkers had around 26% contamination. But when it came to ice, as many as 92% samples were found contaminated. We learnt that many manufacturers were using water from non-potable sources," Dr Khetrapal said.
The city has only 13 official ice manufacturers, though many more could be operating under the radar.
The contamination found in the samples also corresponds with a marginal increase in cases of water-borne ailments such as gastroenteritis, typhoid and cholera. Around 920 cases of gastroenteritis were reported in May and over 848 in April. Three cases of cholera were reported in the last two months. Cases of typhoid, too, jumped from 99 in April to 113 in May . "Though not all E. coli is devastating, the bacteria has a potential to kill; it can cause infections of the gut, urinary tract, and bloody diarrhoea in acute cases. Some patients may need antibiotics and hospitalization," said Dr Om Srivastava, infectious disease consultant.
Gastroenterologist and endoscopy expert Dr Amit Maydeo said the findings could mean there is widespread contamination in drinking water. "A simple way to prevent long term health damage would be to drink only boiled water."