Such as what?
Well, there is blight, fungus, mildew, rot for starters in the organic phase. And, keeping all of the insects out of the environment is an impossibility. They will sneak in no matter how careful the process in monitored.
Then there is the ethylene gas the ripening fruit and vegetables emit. That has to be scrubbed out or the crop will spontaneously ripen uncontrollably.
Then the soil has to be fertilized, with chemicals, or a chemical solution used to grow the plants in.
It really isn't simple or cost effective.