The union has strong relationships with more than 10 countries including Chile, Argentina and Japan.
The International Union of Food Workers is the umbrella organisation for food processing, agriculture, catering, hotel and hospitality unions around the world. Mr Ritchie will be advocating on behalf of the catering industry and will later negotiate with transnational corporations to make sure the union standards are respected wherever they operate from.
Mr Ritchie said the union worked to eradicate child labour and ran campaigns about abuse of workers' rights, from the extremes of members being murdered in some parts of the world, to others being dismissed for exercising their right to join a union.
The move is a significant one for Mr Ritchie, his wife Jane and daughter Kate, who plan to follow him to Geneva at the beginning of next year.
His three adult sons live in Perth and Wellington.