Briefs: Accuracy of temperature-measuring equipment
Food Refrigeration & Process Engineering Research (FRPERC), University of Bristol (UK) has conducted studies on 3 types of temperature-monitoring equipment. The temperatures were measured between mock (tylose) food packs in 3 retail cabinets. Digital instruments, liquid-crystal strips and infra-red thermometers were compared. Liquid-crystal strips were on average the least accurate. Digital instruments were the most accurate and the average error was less than the +0.5°C allowed in UK food hygiene regulations. The infra-red and liquid-crystal devices indicated surface product temperatures, which can be rapidly affected by changing air temperatures. The emissivity of the product surface and incidental radiation from surroundings also gave rise to inaccuracies. It was concluded that liquid-crystal and infra-red instruments are easy to use and less expensive than digital instruments, but that for accurate and portable temperature measurement, digital instruments were vital.