A Washington dairy is recalling its raw (unpasteurised) milk because it may be contaminated with E. coli, according to a news release issued by the Washington State Department of Agriculture (WSDA) at the dairy's request.

The recall, which covers all expiration dates, was voluntarily initiated by the dairy after the routine monthly sampling discovered toxin-producing E. coli in a skim milk sample.

There have been no reported illnesses related to the recalled milk and investigations have started to ascertain the source of the problem.

Owners of the dairy, which has been in operation for 2 years, confirmed that they had started selling raw milk only 3 months ago. With the recall coming so soon, they have decided that in future all milk will be sent to a processor for pasteurisation.

"We realize we took a risk" said co-owner Anita De Boer. "It (raw milk) is a really good product, but there's a risk with it."

This latest recall marks the third recall of raw milk involving dairies in Washington state in the past 4 months. Four children required hospitalisation after being infected with E.coli following the consumption of raw milk.