Hello there,
My Uncle Dan would be upset if I did not correct you in stating that FTO for Fair Trade Organic is actually an acronym and not an abbreviation. Uncle Dan also got mad when I used to talk about my GPS system, but that is another story.
There is an acronym HTML tag http://www.w3schools.com/tags/tag_acronym.asp but I am unaware that Google actively uses it. I would answer your question as follows.
- Is there search volume for the acronym and when you search for that acronym, what type of pages does Google show? In other words are people searching for it and does Google know what it means. When I search FTO https://www.google.com/search?q=FTO I get a pages related to the FTO gene http://en.wikipedia.org/wiki/FTO_gene that is related to obesity and also Fresh Touring Origination a sports coupe from Mitsubishi
I tried "FTO vegetables" but I got instructions on how to make lacto fermented vegetables - I could not find FTO on the page with the instructions though. Results 5 and 6 looked to have to do with fair trade vegetables. I Googled "FTO food" and got sites for "Fresh to Order Food" and "Food Truck Outfitters Atlanta"
My point is, if most people don't use FTO to represent Fair Trade Organic, then Google probably will not, but it still may understand it in the context of use with other words. It may be that FTO is searched a bunch, but it may not be the searches you want.
- Based on my 30 second assessment above, you may want to consider using the acronym in combination with the words Fair Trade Organic and that would work. You need some variety of the words on the page. That goes without saying. I would not though, use it as the primary words in place like your title tag, h1 etc. Makes more sense in the body of the text on the page.
Specifically, "would it provide a weaker result" ? It depends. I would say for FTO searches, you would probably not show up as Google potentially does not associate FTO with Free Trade Organic. For "Free Trade Organic" (full keyword) related searches, I would use it, but not as much as other keywords that are probably searched more often and are more relevant in the results as you need to vary up your keywords anyway.
Hope this helps!