France and Spain were hit on Tuesday by a dioxin contamination scare that has forced the closure of almost 200 Dutch farms after the cancer-causing toxin was found in animal feed.

The European Commission and officials in the Netherlands, Germany and Belgium, where contamination was previously found, have ruled out serious risk to public health but farms have been shut pending the outcome of tests.

The Dutch agriculture ministry in a statement said that two cows from one of the contaminated Dutch farms were exported to Spain.

It also said German-made clay that is used for sorting potatoes for animal feed, and which has been found to be contaminated with dioxin, has shown up in France as well as in Belgium, where it was known to have been exported.

Officials said last week that contaminated animal feed, made of potato peelings, had been bought by hundreds of Dutch cattle, pig, sheep and goat farms and shipped to Germany and Belgium.

The dioxin outbreak has led to the temporary closure of a total of 197 Dutch farms, eight farms in Belgium and four in Germany.

Authorities are still examining the feed and animals and any impact on the food chain, such as in meat and milk.

The results of eight samples of pork from some of the affected Dutch farms proved negative on Tuesday but authorities said all farms involved will remain closed until all necessary tests are completed.

Earlier Dutch results have shown contaminated milk at only two of the farms.

The contaminated animal feed found last week was from the Dutch factories of privately held Canadian potato chip maker McCain, which has halted feed sales.

“New research has shown high concentrations of dioxin in peels from another Dutch potato company.

This has led to closure of another 76 livestock farms (on Tuesday), which had bought contaminated feed,” the Dutch farm ministry said.

It added that contaminated German clay was purchased by a total of 10 Dutch companies and also sold to Belgium and France. The ministry refused to name the companies.

The ministry revised once again the number of farms it closed in the Netherlands last week to 121 from 162, saying it miscalculated the total because of the type of animals they had.