Plastic items turning orange or pink in a dishwasher
If you see this problem in your dishwasher, it is not caused by a fault and is, therefore, not necessary to call an engineer as he won’t be able to bring the plastic back to its normal colour.
Why has this happened:
- This orange or pink colour on plastic is caused by a tomato based foodstuff, such as ketchup. This type of foodstuff contains pigments which are called carotenoid
- Fatty or oily foods will increase the risk of this type of discolouration
There is no need to be concerned, there are no harmful effects from this discoloured appearance.
These red pigments are contained in such foodstuffs as tomatoes, baked beans, tinned spaghetti, plus other items of food colouring used in curries, including some items such as turmeric.
The red pigments are dissolved in any oil which is present, and this is then suspended in the washing water. This is then absorbed into the plastic in your dishwasher. This can be plastic dishes as well as items such as the spray arms or the cutlery basket
How to cure the problem
Unfortunately you cannot remove this colouring by using bleach, as the actual colour has been absorbed into the plastic. The only way this pigmentation can be removed is to the stand the items in direct UV sunlight, although to be fair in the UK, this could take a considerable time
How to stop this happening
You should make the effort to rinse away the residue of any or all of these foods under hot running water before loading into the dishwasher. This is always good practice anyway for ‘mucky’ plates. Anthing really that has a residue of sauces or gravy.
If you want to keep your plastic looking pristine, try to avoid washing together with any dishes that may contain any of these carotenoid products.
One more thing you could try, is to use a better quality dishwasher detergent. By a system of trial and error you may be able to avoid this problem.