Q: Dear Flash,
Why is it that I can’t bring kumquats—or any number of other fruits—over the border from Mexico, but I can buy Mexican kumquats at the grocery store? How do they know those kumquats are safe and others aren’t?
A: Dear Fruity,
You’ve asked a big question; but the short answer is that fruits with the potential to carry infectious plant diseases or insects must be imported very carefully and harvested from known sources tested to ensure they're clean. Of course, contamination still happens. I guess that’s just the price we all have to pay so folks like you can have your weird tropical fruits.