Detectable pens, such as from Detectapro, include a special group of markers and pens that are designed to do amazing things. They are categorized as "detectable" pens because the ink is detectable under otherwise complicated and difficult circumstances. The following sample of detectable pens are most commonly used with food. 

Metal Detectable Food Pens

These pens can detect toxic levels of certain metals that have contaminated food. The marker ink itself is completely safe for human consumption and completely natural. However, the inks will immediately pick up on mercury or lead on meat or produce. It is an invaluable tool to food processing industries. 

Counterfeit Ink Detection

These highlighter-like marking pens are usually yellow in color. When the ink comes into contact with counterfeit paper money, it changes color and is readily detected underneath a small black light scanner. If you operate a business and collect cash from customers, you need counterfeit ink pens and the black light scanners. A detectable pen company can help you with the pens, but you will have to get the scanners from a business supply company. 

Cryo-Wet Ink Resistance

Imagine pens or markers that can write both in cold freeze warehouses and write on wet labels after you smudge off frost or ice. These pens can. It makes them excellent for writing dates and contents of packaging on frozen foods that you want to put in your chest freezer, but you do not want to leave these items in the chest freezer for too long. It is not fun to discover ground beef that cannot be identified as ground beef that you put in the chest freezer over a year ago. Date the bag, box, or foil wrap and a couple words to identify what the contents are. Then you can freeze it for up to a year before you should throw it out, all thanks to your cryo-wet ink pen. 

Inversion Writing

When you have to write as though you are on your back in the Sistine Chapel, it helps to have a pen that will continue to write against the flow of gravity. Many of these sorts of pens and markers were originally designed for astronauts in space, who are writing in zero gravity. If you have need of such a pen to write even when the environmental conditions should prevent ink from flowing to the point, invest in a box or two of these for both personal and business use.