Austria’s Linz-based company Prolactal said Sunday contamination of its cheese which caused eight people to die from listeriosis was due to human error during the manufacturing process.

In November 2009, preservatives supposed to prevent the development of listeria in cheese were accidentally replaced twice "by cultures that do not give enough protection", the company said in a statement.

The cheese was recalled on January 23. Eight have died in Austria and Germany from eating the contaminated dairy product.