Jan Hulsen pointed us to a handy checklist from Attica Cows.
Check is you're washing your milk containers correctly in four questions:
1. Are the containers rinsed before going into the wash water?
2. Are the containers washed in hot soapy water with chlorine?
Are they brushed vigorously?
3. Are the containers rinsed in an acid solution after washing?
4. Are the containers allowed to completely dry between uses?
You can find the full checklist here>>
Includes an option to rate yourself on 5 points.