Signs
One of the signs of mildew in your washer is clothes that smell bad even when removed right after the wash cycle completes. Some people may also have allergic reactions to mildew.
Causes
Mildew can grow on the front door gasket (the rubber seal on the opening of the machine) or in the detergent dispenser, due to moisture or dirt residue.
Solutions
To eliminate mildew, run an extra hot water cycle with bleach. Some manufacturers recommend using a special washer-cleaning tablet. Alternatively, clean the detergent dispenser and door gasket with a mixture of water and bleach or vinegar.
Prevention
Consumer Reports recommends using warm or hot water washes whenever possible. Wipe the door gasket and glass dry between washes, and clean the detergent dispenser at least once a month. Use the right amount of high efficiency detergent, and leave the washer door open between uses to dry out the machine.
Warranty Issues
Consumer Reports recommends documenting any service calls you make due to mold or mildew problems.