"Press release. 16/03/2012
Every individual hosts 100 trillion gut bacteria which obviously play an important role in digestion of food constituents, but also in education of our immune system and our health in general. Today, scientists consider all these bacteria, known as the gut microbiota, as a true human organ..."
http://www.international.inra.fr/press/metahit_bacteria_new_organ

"Press release. 20/04/2011
...In a new study, the consortium of researchers shows that individuals fall into one of three different groups according to the bacteria present in their intestinal tract and independently of their place of origin, their state of health (obesity or inflammatory bowel disorders), gender or age. Like a person’s blood group, this classification is specific to each individual, which led researchers to use the term “enterotypes”...
...We have at least ten times as many bacteria accompanying us as we have cells..."
http://www.international.inra.fr/press/intestinal_flora_can_differentiate_individuals

"Press release. 03/03/2010
...The metagenome has 150 times more genes than the human genome itself...
...Unlike the human genome, however, the genomic content of these bacterial communities were largely unknown to date. The reason? As they lived without oxygen, safe in our bowels, in a milieu that was difficult to characterise and reproduce, most of them could not be grown in a lab..."
http://www.international.inra.fr/press/uncovering_the_genetic_secrets_of_intestinal_bacteria

MetaHIT: Metagenomics of the Human Intestinal Tract
http://www.metahit.eu/index.php?id=536

Health Research Projects in Europe: MetaHIT
http://www.youtube.com/user/microbiome

Seems that soon we will be talking about metagenome instead of "simple" genome.

The Human Metagenome
http://www.youtube.com/watch?v=yd6bZckrkWE&feature=bf_next&list=PL049556381642972A&lf=plcp

So, every individual can be mapped to one of the 3 enterotypes (intestinal microbial markers).
I wonder will that put more sense in talks about taste, maybe a group of people within the same enterotype have similar taste ?

I still have a gut feeling that enterotype has something to say about "taste".
"An enterotype is a classification of living organisms based on its bacteriological ecosystem in the gut microbiome. The discovery of three human enterotypes was announced in the April 2011 issue of Nature by Peer Bork and his associates.[1] They found that enterotypes are not dictated by age, gender, body weight, or national divisions.[2]"
http://en.wikipedia.org/wiki/Enterotype

Talking about humans "the picture" is bigger than that.
"An organism's complement of microbial inhabitants has been called a "forgotten organ".[4]"

"The human body contains over 10 times more microbial cells than human cells, although the entire microbiome only weighs about 200 grams (7.1 oz).[1][2]"

"The human microbiome consists of about 100 trillion microbial cells, outnumbering human cells 10 to 1.[21] Thus it can significantly affect human physiology. "

http://en.wikipedia.org/wiki/Microbiome

http://en.wikipedia.org/wiki/Human_microbiome

But it's not about humans only, it's about animals, and plants too.

So, before I do something to my citrus next time I should think how my action could affect their microbiome. Acting in a "Good Will" manner is not enough, a bit more of knowledge is always welcome.

In real it is even much more complex ...

Thanks iviac, very interesting.