|appliance resource center|
dishwasher troubleshooting: food residue left on dishes
Older, American-brand dishwashers cleaned by filling with water, washing, emptying the dirty water and refilling with new water, etc. etc.
So between fills, the dirty water circulates and over time, food particles clog the spray arms.
Years later, the spray arms — now clogged — spit out the old junk during the final rinse. And voila: clean, yet speckled, dishes.
To remedy this, simply clean out the spray arm nozzles with an old toothbrush.
Now some models of American dishwashers incorporate filtration systems (like European models always did) that keeps food particles from recirculating back into the water.
Check out the 5-stage filtration on GE dishwashers and the triple filtration system on some Frigidaire dishwashers.
Also, the filter decreases water turbidity (translation: the water stays cleaner), making these models much more water efficient.