Microbes share our food whether we want them to or not. We need to control microbial proliferation in foods in order to avoid spoilage, to enhance flavour and, most importantly, to reduce the risk of food-borne illness. A broad spectrum of interventions are available to control microbial growth, but the most widely used is temperature. The use of temperature to control metabolically active bacteria is discussed briefly in the context of current practices. The marketing and legislative climate has provided an impetus to develop an ever-widening range of systems for microbiological control. This short review highlights some of the problems associated with such novel control systems, including selection of new spoilage agents or food-borne pathogens, and the difficulties of monitoring the efficiency of microbial control in the light of a better understanding of bacterial physiology.