The tester is a very useful tool for the catering industry. It is often used in restaurant kitchens, canteens, national and multinational fast-food chains, school cafeterias, hospital cafeterias, catering services, and self-service bars. The tester detects the ideal temperature of the oil in the fryer while foods such as potatoes, meats, and fish are being cooked. It also detects a crucial value regarding the maximum level of polar compounds in oils and fats, which by law must not exceed 25g per 100g. Thanks to the convenient display, reading the temperature and percentage of polar compounds is simple and immediate. Furthermore, to protect customers' health and avoid exceeding the percentage of polar compounds, the tester has 4 LEDs above the display that, depending on the color of the LED and the emission of a beep, notify the cook or fryer operator of the necessary oil replacement in the fryer to avoid violating Articles 5 and 6 of the law dated April 30, 1962, and incurring consequent penalties. In countries such as the United States and Australia, where TPM is not a legal limit, the parameter is increasingly used by catering operators as an internal reference point. Some countries use the acidity index (AV) or free fatty acids (FFA) as a quality standard. According to the official methods and recommended practices of the American Oil Chemists’ Society, FFAs can be obtained by dividing AV by a factor of 1.99.