According to the article Extending the Shelf Life of Fresh Sliced Mushrooms, it states that 5% (v/v) hydrogen peroxide is an effective means for the preservation of sliced mushrooms.
In regards to the preservation:
In the USA hydrogen peroxide is an approved bactericide for some dairy products and is used for disinfecting fruit and vegetables. Its activity is due to its oxidising effects on bacteria and it also bleaches mushrooms during the soaking period.
How does oxidising effects cause the bleaching, hence preservation of sliced mushrooms?