Ordinarily when a fly touches a liquid food it infects the liquid with its pathogens, so it must be dipped in order to release also the antidote for those pathogens to act as a counter balance to the pathogens.
Kwa kawaida nzi anapogusa chakula kinachomiminika huathiri kimiminika kwa vijidudu vyake, hivyo ni lazima kumchovya ili aweze kutoa viuasumu vya vijidudu hivyo kwa lengo la kusawazisha vijidudu hivyo.