Testing devices (calibratable and / or verifiable) for precise hygiene and food testing in hotels, restaurants, catering establishments, canteen kitchens, bakeries, restaurants and of course in hospitals, nursing homes and butcher's shops are becoming increasingly important. The hygiene / food testing device is indispensable for determining the bacterial count, monitoring ventilation systems and maintaining the cold chain in the food sector, for example. Hygiene plays a special role in this type of business.