Durable High-Temperature Humidity Sensors for Precision Food Processing

Most commercial humidity sensors in the market are polymer-based sensors primarily aiming the applications at low temperatures (below 60 °C). Some sensors can operate at high temperatures (up to 125 °C) and a few could be used in bakery processes up to 180 °C. However there has been a concern for the long-term integrity of polymer materials in hot humid environments. Our preliminary studies at Washington State University (WSU) found that the commercial polymer humidity sensors significantly drifted (8%) after only one month of exposure to a harsh environment (90 °C 80% RH). This level of drift may lead to an under- performed pathogen control process and thus increases the risk of food contamination. The food industry also lacks a tool/method to test/re-calibrate humidity sensors under those high- temperature food processing conditions. Building upon ZDC Tech's experience in high- performance solid-state (non-polymer) humidity sensors we propose to create a novel high- temperature humidity sensor for food industrial applications in a harsh environment at high temperatures up to 300 °C. We will also carry out preliminary studies of stability of sensors at high temperatures similar to food processing conditions. The overall goal of this project is to create a durable solid-state humidity sensor and calibration methods for the food industry for high-temperature food processing control and monitoring.