Task: Question Answering
Input (English): If you really want to eat something like lettuce , it has to be washed first in a diluted bleach solution , which in Bolivia at least can be brought in most supermarkets and pharmacies . Lettuce in particular is mostly made of water , so its always going to be risky , plus those little leafy bits are perfect for harbouring bacteria . Most people just avoid lettuce and other fresh non - peelable veg altogether . 5 ) Meat and dairy . 
Question: Why does lettuce have to be washed first in a diluted bleach solution ?
Output (English): Because that's the best way to kill bacteria .