I put citric acid powder and some white vinegar in every rinse cycle. I put it in the cup where the fabric softener would normally go. I cannot use fabric softener due to skin issues, and I use it to help rinse more fully and to soften my very hard water some, leaving the clothing a little softer feeling. I understand that it is also good for the machine, as it keeps it cleaner inside. This has been my habit for more than 20 years, and I've never had mold or any other problems with my front loaders.

As to the amount, I put in a heaping tablespoon then pour in the white vinegar until no more will fit. If you are doing it as just an occasional thing, I would fill the cup then open the machine during the rinse and toss in maybe half a cup more of the citric acid powder.

Downy Rinse & Refresh contains citric acid and it smells good, too..

Just what everyone needs. More chemicals. Rinsing should be pure water nothing else. A machine telling you to sanitize with anything other than extreme hot water is a gimmick. Also these products that claim to sanitize your laundry are total bs. You get perfume in detergent, then some use scent beads, and then some use scented fabric softener on top of that...it is just gross. Must be everyone's germy clothing spreading all these viruses as of late, not. Chlorine bleach kills germs, but use limited to white clothing etc. Chlorine bleach also contributes to corrosion, which is why Miele frowns on its use. Miele uses citric acid in their descaler product only to clean the drum. Furthermore I don't believe any manufacturer on USA soil sanitizes the drum on a washing machine's CLEAN cycle. Miele does, not sure about Bosch. When will everyone realize all these additives are no good for you or your machine. Less is more period.

It is diffucult to wrap my brain around the idea that citric acid will sanitize laundry.