The presence of Escherichia coli (EC) microorganisms in live organs can cause foodborne illnesses and food-related deaths. Here, EC assay was performed using a microcopper three-electrode (MCE) system, where a handmade MCE was used as a working electrode and Ag/AgCl as reference and platinum counter electrodes. Under a EC standard, the diagnostic optimum conditions were sought. The analytical oxidation potential was obtained at V via positive scan. Under these conditions, the stripping linear working range was attained with mg/mL EC variations. A statistic relative standard deviation of (n=13) was obtained by mg/mL EC using sec accumulation time. Under optimum conditions, the detection limit was mg/mL. Here, the diagnostics were explored real-time in the blood vascular system of a live frog. Moreover, which probe can be used for in-vivo clinical application in animal organs (heart, colon, lungs, and gallbladder) was determined as the patient’s peak current increased a hundred times more than in the negative tissue. The sensing time was only 30 sec. This method is simpler than the common PCR amplification, electrophoresis, and photometric detection methods and can be useable for fluorescence analytical catheter probe. | In-vivo Assay of Escherichia coli microorganisms in a live organ using Voltammetric microprobe