"This root cause analysis identified the temporary cultivation of Amadea and Amflora plants in the same physical space in the early seed propagation stage as the cause for the co-mingling," BASF wrote in a statement.
The head of its plant science division, Peter Eckes, was quoted as saying, "We traced back the cause and can narrow the comingling down to a part of our harvest in Sweden.
He added, "The mixup occurred because Amadea and Amflora plants were in close proximity to each other at our facilities. We regret this very much. To prevent such mistakes in the future, we will ensure complete separation of the production systems for Amadea and Amflora."
Amflora has been cleared for cultivation in the Czech Republic, Germany and Sweden, but Amadea has not yet been approved by European Union authorities.
The two strains of starch potato are designed for industrial uses such as the manufacturing of glue and paper but not for human consumption. BASF said it would discard the harvests from all the affected potato fields in northern Sweden, an area that covers around 16 hectares.