If it is not Daddies, HP or Branston and is indeed Asda's own brand, there are probably sub atomic weevils in shell suits befowling it. The trace amounts of their vile excretia is only released when plonking them on their heads. Your rarebit may have an extra tangyness but your brain is now irretrievably altered and you will find yourself craving white lightning served out of a sweaty trainer whilst dancing involuntarily to old Neil Diamond hits. Serves you right.