Breast milk is the best source of nourishment for infants and their is no equal to it whatsoever. However, when for genuine reasons parents resort to infant formula, they quickly discover another problem. Bottle-fed babies often get their tummies upset and sterilization is a major issue with formula feeding. This can be due to contamination of milk, poor sterilization or several other reasons. There are many articles available on the web regarding common sterilization techniques such as using boiled water, electric sterilization as well as their respective advantages and disadvantages. What I have listed here are the finer issues there are easier to be overlooked regardless of your method.
Wash hands with soap and water
Before you proceed with sterilization, make sure that your hands are washed well with soap
Also boil formula spoon:
Boiling formula spoon is a good idea specially if the spoon is left out in the open or on top of the lid of the formula's can.
If you are are boiling water to sterilize the feeding equipment, make sure they are completely submerged in the boiling water.
Keep the lid closed:
At the time of boiling, insure that the lid of the utensil is closed.
After taking out equipment,assemble as quickly as possible
This insures that individual components specially the internal ones like nipples don't get bacteria on them. You should assemble them as soon as the sterilization is complete and place them in a safe place as mentioned above.
Ideally, you should use the sterilized bottle as soon as possible. You can keep them for up to 12 hours if stored in a covered place.
Don't expose the feeding equipment to air till needed
The bottles should not be left out after being sterilized. They should be tucked away in a covered place such as your cupboard or any other place that is not exposed to air. Make sure that this equipment is not unused for more than 12 hours.
Clean and disinfect the work surface used for feeding
The working surface is where you place the bottles and prepare the formula. If the place is not clean and disinfected, there are high chances that the bottle would get the bacteria from there so keep it clean at all times.
Best of luck for a safe and healthy feeding experience for you and your baby.
(Note: I have gathered these points from various resources online and by implementing these measures my son has been bottle fed for over 9 months without any episode of diarrhea)