Search Challenge (3/11/15): Is the fruit getting sweeter?

It seems unlikely, but who knows? Maybe it's true.  

Today's Challenge comes to us from Regular Reader Miguel Viterbo.  Last week he wrote with an interesting question.  With his permission, I'm just going to quote his question as he sent it to me because it's a great example of the kinds of questions that we want to be able to answer.  (In fact, his writeup is much better than most.  Research questions are often vague and missing background and context--not here. This is an excellent Challenge statement.)  

My friends, family, and myself, have been noticing that in the most recent years (latest two to four years), fruits in Lisbon, Portugal are much sweeter than they were, especially in supermarkets and big superstores, where fruit was always worse than the one we could buy at local stores. 

Oranges and citrus fruits have been particularly noticeable in their increased sweetness.

We have no idea if this is a global trend, or if it's just true in Portugal.
At first, we tended to assume that supermarkets just got better at dealing with producers and acquired better stuff. In fact, most people I know didn't buy their fruit in supermarkets, so it's reasonable to expect that they had to fix that problem.

In the past months, though, we've heard rumors that farmers nowadays use sugar (or some kind of sweetener) added to the irrigation. Yesterday, the fruit shop owner in my neighborhood (whom I assume to be knowledgeable, because she has been picking her suppliers for 20+ years, and at a time was married to a producer herself, if I remember it right) told me that this was common knowledge (she said, "some time ago those sweeteners were added to the fertilizers, now they're within the irrigation itself").

(1) Is this true? Does this actually work to make fruit sweeter? 

(2) Should I be concerned?  Sugar is already hiding in so many everyday "non-sugar" foods (way more in the US than in Portugal, granted) that I don't want to take any more added sugar.  If it's really more sugar, how much more is it?  

I haven't spent any time trying to research this Challenge.  I didn't want to get a head start on this.  I want to check this out this along with all of you loyal Search Researchers.  

I have no idea if this is true, or if we're going to be chasing down an urban legend.  

That's why this is an especially interesting question:  We don't know how it's going to turn out!  

Let's begin on Miguel's Challenge.  What can you find out about this?  Is it true that farmer's are now adding sweeteners to their irrigation water?  

Unleash the hounds of Search Research!  Go!  

Let us know what you find out AND tell us how you did it. 

Search on.  



- Muito obrigado to Miguel Viterbo for this excellent Challenge.