April 1, 2009
Infrared thermometers can be used in food cooling applications ranging from candy manufacturing to ensuring the right temperature of frozen peas and baked goods.
For manufacturing candy bars, the chocolate is poured into plastic molds. These molds are a thick plastic and are chilled to a temperature of 62°F (17°C) before they are filled with chocolate. If the molds are not sufficiently cooled, then the bars will not be solid enough to be wrapped. Conversely, pouring the chocolate into molds that are too cool can alter the color of the chocolate and make it visually unappealing to the consumer. The temperature of the molds is easy to control with infrared devices because the target is large and the temperature is measured at the exit of the cooler. The color of the molds will not affect the measurement or the emissivity setting required on an infrared thermometer.
Many candy-making processes require sugar or corn syrup to be melted and later cooled to a taffy-like condition. To obtain the proper process temperature, the sugar or corn syrup is poured over chilled rolls. The tendency is to control the roll temperature using contact-type temperature measurement devices to measure the sugar temperature is not practical because sugar buildup would insulate the sensor and result in an inaccurate temperature indication. Infrared sensors can provide improved measurement accuracies in this application. Again, the color and thickness of the sugar or syrup do not influence the thermometer setting.
Frozen food is a big market for the use of infrared thermometers. Products such as frozen corn, peas, French fries and waffles must be cooled rapidly to the right temperature to prevent color changes that would make them unappealing to consumers. They are typically flash-cooled to approximately -36°F (-38°C). In these applications, the infrared instruments are installed so that they measure the food temperature as the food exits the flash-cooling chamber. The instrument is not installed to measure the food in the actual cooling chamber because moisture in the air will interfere with the temperature indication.
In the highly automated production of baked goods such as pizza, accurate temperature measurement is crucial to ensuring process safety. If a baked food product is not properly cooled before it is packaged, it can start a fire that could destroy the process line or, worse yet, cause major damage to the entire factory or warehouse. Infrared thermometers can monitor the temperature of the product to ensure that it is cooled to specification.