If I was looking at a home made product I would seriously look at what the mould outcome was after making it, and if there is a recommended use by date (tenina gives a little indication in her "basic cupboard stock/flavour enhancing" recipes), judge from your own personal experience with "BEST BY / USE BY" recommendations, if the product has been kept in the fridge or frozen. Shelf life woud depend upon the amount of preservative used eg. salt. Call up HO and ask them this question as they publish this recipe, and report back as its valuable information for thermomixers.