1. Contribution from the Queensland Agricultural Biotechnology Centre (QDPI) and the Centre for Drug Design and Development, The University of Queensland, Brisbane 4072, Australia, Laboratoire de Microbiologie Alimentaire, Université de Caen, Esplanade de la Paix, 14032, Caen, Cedex, France, and Centre for Magnetic Resonance, The University of Queensland, Brisbane 4072, Australia