I have used Bicarbonate soda for nearly six months directly on my body diluted with a small amount of water as well as added to the buth but it does neither kill not keep away Malassezia yeast. If it works for some individuals then they are indeed lucky!
I have been buttling this beast for a long time and used many substances both natural ans well as chemical /pharmacy available but so far i can see improvement but cure seems a long way.
My story long and rather severe including photos is detailed in a blog i created recently trying to collate all information which may bring some help both to me as well as to others.
If you have not cured your problem and still seek for information i hope you may find some helpful information there. No selling nor promoting products nor any affiliation with business, just my long experience in all its details.