At Miso Tasty, our mission is to make our products as naturally as possible; preserving the REAL flavour of miso, by not adding any 'nasties'.  Even if it means our shelf life is shorter and we have to sell our products quicker! Every item of food at the supermarket sports a sell-by or use-by date to indicate its safety to consume -- that's just the law.  So what we are doing here is understanding how long our product can survive in its natural state, by laying down product samples and getting them micro-biologically tested once a month to detect technical as well as flavour changes. Thing is,  all products' flavours will change in its lifetime from being made  - regardless of how you have preserved it. For instance a pasteurised juice at 2 months old and 10 months old will taste different. Our mission is to become the most natural miso on the market. Unlike the pastes of our competitors, we DO NOT have ADDED SALT nor any additives so that we bring you the most unadulterated and therefore the yummiest miso you have ever tasted! Miso --  like many wines and balsamic vinegar --  get better and deeper with age, especially the darker varieties. Something that should be celebrated rather than curtailed, in my opinion, but in the world of retail, we must respect these rules..!