When the formula is manufactured, we remove the oxygen from the tin and replace it with nitrogen and carbon dioxide before sealing the tin. This helps slow oxidation and significantly extend shelf life.

Once the tin is opened it is again exposed to oxygen, meaning that the powder starts to ‘age’ more rapidly.  Once a tin has been opened, it needs to be used within 4 weeks. After 4 weeks we can no longer guarantee that the Nutrition Information Panel (NIP) on the package is correct, meaning that you cannot be sure that baby is receiving the nutrition detailed on the package. For a baby under 6 months this is extremely important, but for an older child it is less crucial as they are having additional foods in their diet.

Even though you may be careful about opening the tin every time you use it, each time the lid is opened the formula is exposed to potential contamination. As the formula is a food source for babies as well as potential bacterial contamination, keeping a tin past four weeks may put your baby at risk of a tummy upset.

Each product has a ‘limiting ingredient’ (usually encapsulated fish oils), and this may spoil after the can has been open for a month, making the product quality and taste less than ideal.

It is a good idea to put the date you opened the tin on the plastic re-closure lid. This way you can keep track on how long a tin has been open.

Storing an open tin in the fridge or freezer is not recommended either as moisture will get into the powder and cause clumping.