TABLE OF CONTENTS The microbiological world is both complex and diverse, impacting on almost every facet of human life in ways that are often poorly characterised, let alone understood. The scientific, social and economic impact of new and improved techniques for measuring the microbiological content of both natural and artificial environments could be immense. In this respect methods that enable the rapid, accurate and selective sensing of microbiological species will have enormous potential benefits.
Even within a relatively closed environment like a food processing plant a wide range of microbiological particles can exist, often in very small concentrations. Any method of monitoring or analysing the microbiological make-up of the sampled environment must overcome the problem of isolating a potentially low concentration of the particles of interest from an often diverse population. Such real world samples do not readily lend themselves to the biochemical or serological tests usually applied and the species under test must be pre-concentrated or selectively enriched, for example by bio-culture growth, prior to most chemically based analyses. Whilst these essentially chemical methods can be highly species specific, they are time consuming and inflexible, often requiring controlled environments or laboratory conditions.
Electronic sensors, or sensors that can be readily interfaced with electronic instruments, in principle offer the advantages of speed, high sensitivity (for example, impedance changes of 1 part in 10 9 can be detected), robustness and flexibility. Yet any practical electronically based micro-biological sensor must be able to pre-concentrate, detect,...
