I have the Professional 600 stand mixer and had always washed the blade by hand and had no issues until my daughter put it in the dishwasher. The blade discolored and had a black dust on it. I called to inquire about this and was told the blade oxidized from the detergent and I should clean with baking soda and lemon juice solution every time it is washed even if washed by hand. There is no stainless option for the 600 only the white coated option that other reviews say it flakes off over time. This is very disappointing that a stainless option is not available