At its production plant in Avedoere Holme, south of Copenhagen, Chr. Hansen — a Denmark bioscience company that develops natural ingredient solutions for the food, nutritional and pharmaceutical industries — produces bacterial cultures used by food producers such as Dannon and Nestlé to make yogurt and other sour milk products. To eliminate any contaminants that could pollute or destroy the final product, the nutrient solutions are sterilized by ultra high temperature (UHT) treatment before being transferred to a fermenter.
In the UHT process, the solution is exposed to temperatures above 282°F (139°C) for several seconds. A safe sterilization can only be guaranteed if the temperature does not fall below the minimum temperature at any time. Thus, if the temperature drops and approaches the minimum required temperature, a quick reaction by the control system is necessary to counteract the temperature decrease and heat up the system again. This requires an accurate temperature sensor with a fast response time.