A baby's immune system is immature when born. It is for this reason that all the baby's feeding and formula preparation equipment (and dummies) should be sterilised for at least the first 6 months after birth. However, it is important to keep preparing milk formula in a hygienic manner, to reduce the potential growth of bacteria in the formula milk. Many parents will continue their sterilising regime with their formula milk bottles up until their baby is 9 to 12 months old (or are on a normal adult-like diet).
There are 3 main ways you can sterilise bottles and equipment. These are:
No matter which method of sterilisation you choose, you need to prepare the bottles and equipment before they are sterilised. Even if the sterilisation process is carried out correctly, the bottles and equipment will not be made sterile if they have remnants of milk left on them. Therefore soon after feeding, discard any unused milk from the bottle and rinse it, the teat and cap in cold water. Do the same with the formula preparation equipment, as soon as possible after preparing the formula.
Once rinsed, scrub all the equipment in warm to hot soapy water (using dishwashing liquid). Use a bottle brush to clean inside bottles and inside teats (or use your finger or turn the teats inside out to clean inside them) and squirt water through the teat hole to make sure it is not blocked with milk. Give dummies a good scrub as well.
After cleaning all the equipment with hot, soapy water, rinse it all thoroughly in cold water. Again, squirting water through the teat's hole to rinse it well. Now everything is ready for sterilising.