The Dutch agriculture ministry on Wednesday temporarily shut 140 cattle, pig, sheep and goat farms after cancer-causing dioxin was discovered in milk produced by two farms, the ministry said.

All closed farms used a special potato product to feed animals, which the ministry said had been contaminated with dioxin.

“The closure is a prevention measure because we want to investigate whether there is dioxin contamination in the other farms and a spread into the food chain,” a spokeswoman for the ministry said.

The spokeswoman said a result from the investigation could be expected next week.

Contaminated feed was at the root of recent European food scares such as the discovery of an illegal hormone in Dutch pigs in 2002 and the 1999 Belgian scandal of dioxin in chickens.

Dioxins are one of a number of toxic chemicals that originate in pesticides or industrial processes, leach into rivers and lakes and build up in the flesh of fish and animals.