One of the ways to get this vegetables fresh is to thoroughly preserve with getting them isolated from all kinds of dirt.
What I mean is to get them thoroughly washed because most of the things(pathogenic soources) that cause disease, that is, unusual look in this vegetables ARE inherent in the dirts that accompany the vegetable from pre-harvest to harvest.
By pre-harvest I mean  that before the harvest of these crops, and we all know that pre harvested crops encounter soiling on the field. The obvious way of soiling is attachment of soil particles that carry germs in them.
Pathogen by means of entry into the plant tissue gain entry into the tissue of the plant that causes future  changes of ten observed in the vegetables we see them often as watery water soaked appearance on the leaves.
The environment has a way helping these organisms that cause organisms that grow rapidly in the tissue of the vegetables.
It is unusual to find  soiling on the tissue of leaves and you would not find these effects that are often observed.
For me I have coined the word misplaced priority the theme for this kind of thing.

I mean that the organism that requires food has to go to environments that is capable of allowing its growth. 
The growth factors that allow optimal growth and by me, meaning the desired maximum growth are often seen on our day to day life style.