A mechatronics engineer works to automate the transfer of materials and goods, and the manufacturing process. Their tasks involve identifying areas for task automation, designing, developing and testing potential mechatronic devices, and implementing design solutions.
A typical tea bag has somewhere between a gram and two grams of stuff in it. If the entire contents were nothing but fructose, and that fructose completely dissolved when you made your tea, you'd consume between 4 and 8 calories (carbohydrates contain 4 calories per gram) per cup of tea -- so that's the ceiling.
First of all, you'll need to store the tea bag in a moist medium. Once they get dried out, they become a breeding ground for mold and bacteria. So your best bet is to store them in a small shot glass filled with water. That will keep them seeping while they are being stored. While you can leave them out in your kitchen, I usually put them in the fridge so that there is less chance of bacteria growth. If you think you've got bacteria or mold in your tea bag, the best indicator is smell. If it smells funky, trash it. A tea bag can be reused one or two times. After that, it's spent. Reusing green or white tea works better than darker blends. I usually reuse Orange Pekoe tea bags because I use two bags in one cup: I like strong milk tea in the mornings, with milk, no sugar.