private static function splitKeywordTagOnSemiColon(
        CultureFeed_Cdb_Item_Event $event
    ) {
        $event = clone $event;

        /**
         * @var CultureFeed_Cdb_Data_Keyword[] $keywords
         */
        $keywords = $event->getKeywords(true);

        foreach ($keywords as $keyword) {
            $individualKeywords = explode(';', $keyword->getValue());

            if (count($individualKeywords) > 1) {
                $event->deleteKeyword($keyword);

                foreach ($individualKeywords as $individualKeyword) {
                    $newKeyword = new CultureFeed_Cdb_Data_Keyword(
                        trim($individualKeyword),
                        $keyword->isVisible()
                    );
                    $event->addKeyword($newKeyword);
                }
            }
        }

        return $event;
    }