Sensor Sticker for Detection of Fungi Spore Contamination on Bananas
Fungi growth on bananas during transportation not only results in loss of food but it also incurs considerable transport losses. To investigate the influence of spores on the development of fungi growth on the bananas we present a sensor sticker. The sticker can be put on the banana surface for the detection of spore concentration. The designed sensor comprises of a thin layer of culture medium (PDA agarose) coated on a capacitive sensor fabricated on a polyimide foil (5 μm). As spores germinate, the capacitance of the culture medium changes which is measured by the interdigital capacitive element that contains 2 electrodes (with 428 fingers) that have a length of 3 mm, a width and a gap of 7 μm. In addition to the culture medium one of the major requirements for the fungi to grow is air. As air cannot diffuse through the sticker, air cavities are integrated in the culture medium layer to provide the necessary amount of air for fungi growth. This method was successfully applied to determine different concentrations of Fusarium Oxysporum, a major fungi species responsible for banana contamination. Measured capacitance change after a fixed time interval depends on the initial concentration of spores. The measurement takes typically 6 hours.
P. Papireddy Vinayaka et al., "Sensor Sticker for Detection of Fungi Spore Contamination on Bananas", Advances in Science and Technology, Vol. 100, pp. 130-133, 2017