My racks have mold. Can I use bleach?
Yes, if your dishwasher isn't stainless steel. Stainless steel doesn't like bleach at all, so if you have one like that, clean everything thoroughly by hand the run a cycle with 1 cup of vinegar through it. Use the highest heat setting possible too
Before you start, read this:
I had an issue with one that had been sitting closed for awhile. I put vinegar in a spray bottle and sprayed everything. Then I ran it empty with my hottest water setting and dishwasher detergent. Then, while still wet, after the cycle, I took the racks out, scrubbed them again, rinsed them and dried them on my porch in full sun. I thought running the machine was important in case there was any I couldn't see. A soft brush helps with nooks and crannies. The best small brush I have found for this type of cleaning is a denture brush from the dollar store.
If the racks are plastic coated, you can take them outside and bleach them, but rinse immediately. Bleach is very corrosive.
I would try other methods first.
When you get the mold out, open your dishwasher as soon as the dry cycle ends and let it air dry inside.
I run vinegar through the dishwasher once a month as well as my coffee maker, but I allow both to air dry during the day.