When goods are bought and sold, ownership passes to the buyer as soon as the parties intend it to pass, even if delivery and payment has not yet occurred. This general rule of property law has been expressly incorporated into the sale of goods legislation of the states and territories. See sections 6 and 7 of the module 'The contents of a contract'.
Of course, the duties of delivery and payment must be carried out when due, but ownership in the goods often passes to the buyer before performance of those duties.