The Department of Food Technology says its investigations show that 15 percent of all edible products in the market are adulterated. A 10-month study of 619 samples collected nation-wide revealed that 89 were sub-standard. Over half of all "pasteurised" milk samples tested from Kathmandu markets contained Coliform bacteria, including milk sold by the state-owned Dairy Development Corporation. Bottled water was another major culprit-more than half the samples tested revealed the presence of bacteria. The same goes for edible oils, which contained traces of argimore, a natural product that is said to be harmful to health. Despite this, the department says that the levels of the undesired substances and life forms in food products has declined, compared with last years' findings.