A joke about genetically modified food is:
   
“I don’t know what all the fuss is about genetically modified food. I had a lovely leg of salmon the other day.”
 
The “leg of salmon” GM food joke has been cited in print since at least 2009 and has been popular in the United Kingdom.
   
   
Wikipedia: Genetically modified food
Genetically modified foods or GM foods, also known as genetically engineered foods or bioengineered foods, are foods produced from organisms that have had changes introduced into their DNA using the methods of genetic engineering. Genetic engineering techniques allow for the introduction of new traits as well as greater control over traits than previous methods such as selective breeding and mutation breeding.
 
Commercial sale of genetically modified foods began in 1994, when Calgene first marketed its unsuccessful Flavr Savr delayed-ripening tomato.
       
20 April 2009, Evening Times (Glasgow, Scotland), “The Funniest Way to Start the Week” by David Stirling, pg. 20:
She’s become a fan of genetically modified food, and has been desperate to prove it can be just as wholesome as the grub we’ve eaten for years.

And, to be fair, she baked Nancy and me a very tasty leg of salmon last week.
 
Twitter
❤️ FizzyDuck ❤️‏
@FizzyDuck
All this talk of dangerous, genetically modified, food tasting horrible is nonsense. I mean, just today I had a delicious leg of salmon.
8:48 AM - 15 May 2009
   
10 September 2009, The Herald (Glasgow, Scotland), “The Diary” by Ken Smith, pg. 17:
“I DON’T know what all the fuss is about genetically modified food, ” said the woman having coffee with her friends.
 
“I had a lovely leg of salmon the other day.”
 
Google Books
Jokes for Blokes:
The Ultimate Book of Jokes not Suitable for Mixed Company
By Llewellyn Dowd and Phil McCracken
London, UK: Ebury Press
2011
Pg. 250:
All this talk of dangerous, genetically modified food tasting horrible is nonsense. I mean, just today I had a delicious leg of salmon.
     
Google Books
The Mammoth Book of One-Liners
Edited by Geoff Tibballs
London, UK: Constable & Robinson Ltd
2012
Pg. ?:
I have no problem with genetically modified food. I had a lovely leg of salmon the other day.
 
Twitter
DJay Saunders™‏
@DJaySaunders
All this talk of dangerous, genetically modified food tasting horrible is nonsense. I mean, just today I had a delicious leg of salmon.
11:48 AM - 18 Jan 2016
 
Twitter
Bruce Fraser‏
@BruceybearScot
Talk of genetically modified food not tasting as good is complete nonsense. I’ve just had the most delicious leg of salmon for my lunch.
6:12 AM - 15 Feb 2016
 
Twitter
Unlawful Humor‏
@UnlawfulHumor
I really don’t see the problem with genetically modified food,
I just had a nice leg of salmon.
9:54 AM - 22 Feb 2016
     
Twitter
Shit Jokes‏
@ShitJokes
I’ve got no problems with genetically modified food!
Just had a lovely leg of salmon.
4:15 AM - 18 May 2016
 
Reddit—Jokes
I’m not sure I believe all this stuff about genetically modified food being bad for you…
submitted June 9, 2017 by madazzahatter
I feel fine and I just had a really tasty leg of salmon…