This paper discusses the concepts applied by the food industry to assure the microbiological safety of food products. It considers the development of these concepts and their relevance to the current needs of the industry. It discusses hazard and risk ranking, testing and measurements, design to a performance standard and the application of HACCP. It also considers, in depth, the use of formal risk assessment schemes based on hazard and exposure measurement and some of the difficulties of applying such schemes to measure microbial risks.