how are blockchains used 
as we now know blocks on bitcoin s blockchain store transactional data today tens of thousands of other cryptocurrency systems are running on a blockchain but it turns out that blockchain is a reliable way of storing data about other types of transactions some companies experimenting with blockchain include walmart pfizer aig siemens and unilever among others for example ibm has created its food trust blockchain to trace the journey that food products take to get to their locations 5