Colorado ? State health officials warned residents of a southern Colorado town Wednesday to stop drinking and cooking with tap water because they said it might be linked to a salmonella outbreak.

The state health department said 33 cases of salmonella have been confirmed and 46 other reports were being investigated in Alamosa, a city of 8,500 about 160 miles south of Denver. Officials said that the tap water tested positive for bacteria believed to be salmonella, but that the results had not been confirmed.

Water-borne salmonella outbreaks are fairly rare, said Mark Salley, a spokesman for the Colorado Department of Public Health and Environment. The bacteria are typically spread by food, he said.

Boiling water for 15 seconds will kill the bacteria, but health officials advised residents to use bottled water for brushing teeth, washing dishes, making ice, cooking, drinking and making baby formula. People can use tap water to bathe, as long as they are careful not to ingest it, Salley said.