Today 5,358 species of earthworms have been identified. These worms are first divided into ecological groups. The group know as composters are epigeic and live in surface mulch. These are the worms that will eat your food waste in a bin.
Of these epigeic worms I use Eisenia fetida which is the scientific name for the red wiggler. Although some companies will sell you other composting worms be sure you are working with a reputable dealer. One clue to finding out if the dealer is reputable is to see if they use the scientific name. Using comman names can be confusing and sometimes incorrect. Another way to see if the person you are buying worms from is knowledgable is to see if they are selling invasive worms. If they are selling them then that is problematic.
An invasive species is something that causes economic or environmental harm or harm to human health.
The Wisconsin DNR is working hard for all of us to understand the potential damage of the Jumping Worm or Amynthas  here is their website 
Once at this website you can print off their brochure on Jumping Worms or join me at my next event and I will give you a copy.