Michael Berney, Department of Microbiology and Immunology, Otago School of Medical Sciences, University of Otago, P.O. Box 56, Dunedin, New Zealand. Michael gave his award lecture entitled "How dead is dead?" on survival of pathogenic bacteria in hostile environments. Please find below the abstract of his presentation: Pathogenic bacteria are a general threat to human health around the world and a constant battle is being fought to contain them. A central question in this battle is the efficacy of measures taken against the pathogens (e.g. water disinfection, antibiotic treatment). In order to determine the efficacy of antibacterial treatments, reliable information pertaining to the physiological state of the cells and the mode of action of the antibacterial agent have to be gained. However, accurate determination of bacterial viability has been a long standing microbiological conundrum due to the ability of bacteria to enter physiological states commonly described as persistent, dormant, viable but non-cultivable etc. This presentation will demonstrate how the mode of action and the viability of treated bacteria were revealed for Solar Water Disinfection, a simple, low cost water disinfection method that helps to improve the drinking water quality in geographic regions where no other measures are taken and disease can spread rapidly.