Rapid and sensitive detection of bacteria is one of the key steps in assuring the microbiological safety of food and water. Electrochemical methods for bacterial detection offer the advantages of rapid quantification with minimal equipment. Here, significant efforts were made to improve the sensitivity of electrochemical detection using a variety of strategies. Three electrochemical methods were successfully developed to detect bacteria. These methods have the potential to enhance the safety of food and water by providing a more rapid and reliable timeline from the sampling to results. The first approach targeted the detection of Salmonella in agricultural water, using a combination of immunomagnetic separation and electrochemical redox cycling. Antibody coated magnetic beads were used to capture, separate and concentrate Salmonella from agricultural water samples. Reporter enzyme alkaline phosphatase conjugated to anti-Salmonella antibodies were used to label the bacteria as well as catalyze an electrochemical reaction. Redox cycling allowed the signal enhancement by regeneration of electroactive product on the electrode surface. Despite of the high specificity of antibodies, they are sensitive to environmental conditions, and not able to differentiate viable from non-viable bacterial cells. Therefore, for the next two projects, bacteriophages (phages) were used as biorecognition elements. Phages are viruses that can only infect the living bacterial cells with a high degree of specificity. A phage-based electrochemical method was developed for the detection of E. coli in aqueous samples. Phages were not only used to recognize and capture the target bacteria, but also enabled the electrochemical detection. A gene encoding for the reporter enzyme, β-galactosidase, was inserted into the phage genome. During the initial stages of infection, reporter enzymes were expressed and then released into the sample solution during the final stages of infection. The enzymes in the solution could then be electrochemically detected, which indicate the initial presence of viable E. coli. For the third approach, we further improved this method by engineering phages to express a fusion enzyme alkaline phosphatase which could directly adsorb to a gold electrode via a peptide tag. The incorporation of gold-binding peptides, allowed 1) direct contact of the electrochemically active enzyme and the electrode, and 2) an additional concentration step. This scheme resulted in an overall improved assay format with regard to sensitivity.