An imported meat ingredient from Poland is to blame for the horse DNA contamination scandal, the Irish government has revealed.

Tests on raw materials at ABP Food Group’s Silvercrest plant – one of the sites implicated in the scandal – had found “up to 20%” horse DNA relative to the beef content on frozen meat trimmings from Poland, the Irish department for agriculture, food and the marine said on Saturday (26 January).

“This confirms previous results that the raw material from Poland is the source of equine DNA content in certain beef burgers,” it added.

The department has not named the company that supplied the Polish ingredient, but ABP Food Group stressed it was not connected in any way to its own Polish subsidiary in Poznan.

Irish agriculture minister Simon Coveney said no Irish raw materials had shown any signs of horse DNA contamination. He was quoted in the Irish press as saying this vindicated the Irish food industry.

Silvercrest was closed temporarily by ABP while investigations are carried out. Coveney said strict conditions would be imposed on ABP’s Silvercrest plan when it reopens, including direct scrutiny through government officials for six months, weekly tests on samples and a deep-cleanse of the entire plant. He said this would be part of providing “the necessary reassurance to its customers on the integrity of the production chain”, adding a key component of this reassurance would be ABP’s “commitment to source all its raw materials from Ireland and the UK”.

ABP has also announced it is changing the management at Silvercrest and reorganising its operations in response to the scandal.