That is one of those well-known facts that is actually not entirely true, and apparently under debate in the scientific community.
From what I can tell, the general consensus is:
- Komodo dragons do have venom glands.
- However, the venom they produce might not be "true" venom.
- Komodo dragons keep their mouths relatively clean.
- They do still have bacteria in their mouths, but so does every other animal. A bite from any animal can very easily become infected, even your pet dog or cat.
- The misconception of komodo dragon bites being particularly infectious may have come from instances of injured prey fleeing into dirty water and picking up extra infections there.
- Komodo dragons try to kill their prey outright via lacerations and blood loss, not over time with venom or infections.