This short piece of glass is of great help. It always help us in monitoring temperatures. Temperatures of oven, water, juice, jellies, refrigerator, freezer, air and even body temperature. However, there are other types that do the same function without much risks.
1) Using glass thermometer is indeed risky. Glass is fragile. Handle it with care to prevent breakage. But accidents do happen and cannot be always avoided. Broken glasses might hurt own’s hand, feet if left scattered on floor…
What are you going to do if broken glasses fall in prepared juice? Simple filtering can remove larger pieces but not minute shrapnels that can cause mouth and internal organ wounds when swallowed. Glass is an inert material and no stomach acid can degrade it.
2) DOH Administrative Order 2008-0221 – ban of mercury based thermometers starting September 28, 2010. Many hospitals have implemented the ban long before the indicated date. Dangerous mercury is the reason. Mercury in any form is toxic. It enters the body through swallowing, inhalation and absorption to skin and mucous membranes. Imagine a piece of mercury in hand separated by a thin piece of glass. Scary! Never sure if the order was also effective on food industry.
If the piece of mercury based thermometer is broken and fell to food, then the food should be dispose immediately. Removing mercury and broken glass pieces is not possible.
3) It is hard to read. I have been using this type of thermometer since elementary grade. I always find it hard to read, finding a fine line along a sealed glass tubing.
Switch to dial type or digital thermometer with a stainless steel tip.