What is the most sanitary type of water bottle for preventing odors?

Odor prevention shows what is the most sanitary type of water bottle:

• Why Bottles Smell:
  • Bacterial growth produces odors
  • Biofilm creates persistent smells
  • Porous materials absorb compounds
• Material Comparison:
  • Plastic: Permanently absorbs odors
  • Glass: Retains odors in micro-cracks
  • Medical Steel: Zero odor absorption
• Sanitation Connection:
  • Odor = bacterial presence
  • No smell = true cleanliness
  • Fresh bottle = sanitary bottle
• Testing Results:
  • Coffee test: No residual smell
  • Protein shake: Completely fresh
  • Month-long use: Like new

For permanent freshness, medical steel answers what is the most sanitary type of water bottle.