Hi @kashan you would need a stabilizer of some sort, either a gelatin based or an emulsifier based solution. Even alpha cyclodextrins would work. Otherwise, use a non-dairy solution for your mousse. For example, Cool Whip (vegetable shortening) lasts longer than dairy based cream. If you look at my tropical icing demo in the last clean label cakes seminar (view it in the Academy), you would be able to make your own shelf stable cool whip.