I think that it is likely that for fears such as these (assuming there is no past traumatic experience with the item) they are caused basically by bad connections in the brain. Some neurons somewhere at some point through some unfortunate circumstances ended up wiring together the response to pickles or peaches to those of extreme fear. Once this connection is made, due to the strong response it may be difficult to break.

Wikipedia describes the anatomical response of a phobia:
"Phobias are more often than not linked to the amygdala, an area of the brain located behind the pituitary gland in the limbic system. The amygdala may trigger secretion of hormones that affect fear and aggression. When the fear or aggression response is initiated, the amygdala may trigger the release of hormones into the body to put the human body into an "alert" state, in which they are ready to move, run, fight, etc.3 This defensive "alert" state and response is generally referred to in psychology as the fight-or-flight response."

Also once this fear is established it would be fairly easy for it to grow. Because of the strong response elicited by the trigger item, the brain would strengthen this link between the item and negative results possibly because of things like teasing, laughing, etc.

But this is just my best guess. I couldn't find any better information on the subject.

I grew up with a sister and a few friends that had weird food 'rules'. I think that often these weird habits can turn into full on irrational phobias later in life.

My sister wouldn't eat her dinner if any of the foods touched on her plate. Period!
I remember one time I was angry at her, so I gave her a very detailed visual of what her food would look like all mixed together in her stomach. Needless to say, she didn't eat her dinner that night.

Lon... I remember seeing both of those videos you posted on Youtube and thought they were quite funny, but when you really think about it, those people have just let an irrational fear grow too far. Many fears in relation to food have a connection with choking. Peanut butter is a common food phobia since people envision the peanut butter covering the roof of their mouth and somehow growing and blocking their throat or wind pipe.

This link...
http://www.associatedcontent.com/article/1442176/5_funny_food_phobias_you_dont_want.html?cat=22
not only talks about Arachibutrophobia, or fear of peanut butter, but also about Cibrophobia which is a phobia of all food. Again, this phobia is connected to the fear of choking on anything a person puts in their mouth.

If any of these fears are not treated medically or through therapy, they can grow to outrageous proportions like the people on the Maury Show. On that previous link, some people with Arachnibutrophobia can't even go down the isle that carries it in the store.

Unfortunately, I believe the above guests on Maury's Show... as irrational and crazy as it looks. What p****s me off is that Maury used those peoples fear as an entertainment, and most likely didn't help them to get treatment afterwards.

These food fears are also not as rare as you'd think. I quickly found @rachel in a food forum talk about her fear of mayonnaise, which included scrubbing the skin raw if any came into contact with her.
http://caloriecount.about.com/food-phobias-ft114957

Whether it's the texture, taste, or look of certain foods, there may be links that these phobias were really created by an obessive-compulsive (OCD) trigger in the brain. I'm sure Maury would have the same response if he took an Agoraphobic and tried to drag him or her out of their own house.

It is funny that the female has the pickle phobia and the man has the peach, and I'm sure that the producers of the Maury Show saw the irony there too, but in looking at the larger scope of food fears... I couldn't find any other sexual connections with the exception of the fear of choking... ahem.

I'm not a psychologist or anything, and I don't have much insight into this type of phobia, but I just wanted to add my two cents. One of my uncles is afraid of mushrooms. Like deathly afraid. I've never understood this, but it really fascinates me. It's interesting to hear now that others experience this fear of food as well. There must be something to this.

I like your insight as to the sexual nature of both the peach and the pickle. Maybe mushrooms have similar connotations, but is that the reason for the phobia? Maybe. It may also have something to do with a past experience with the food, that the person has repressed, as @rogercamel says. However, I had some bad experiences with pickles when I was very young, but am not necessarily afraid of them. I just don't eat them. So maybe it's the texture of the food that reminds these people of something else. Perhaps the fear of contaminants. I don't know.

Maybe we'll never know what causes food phobias. Past traumatic events may lead to this, but who knows what sorts of events have made these people begin to fear certain foods over time? It's a strange concept, but I would just think of it like any other phobia. Something happened to cause it, and there should be ways to cure, or at least work on putting these fears away in order to be able to live somewhat normally.

I have no special insights for you on the causes of the phobias.

Even after I've watched entire documentaries, like the one this video comes from. It was about phobias in general, with esp focus on the case of a man who was afraid of baked beans...

http://www.youtube.com/watch?v=3Y8VKs3__cA

As other answerers have suggested, we really don't know why things like this happen. But in general the brain makes associations, and they don't have to be logical associations. For example...

- You win an important soccer match, and you somehow feel it is important to wear the same socks for your next match. (Superstitions like that are common in many sports.)

- Someone looks vaguely like someone you knew as a child, you immediately feel they are your kinda person when you first meet them.

- A song was playing on the radio a lot around the time someone broke up with you. You cannot bear to listen to that song.

- Your mom gave you cookies after school every day. You now associate cookies with being loved and secure.

Basically strong emotions can get attached to anything that was around at the time. And the ones that are so normal like we don't even notice them, like thinking cookies = love, comfort, security, are no more rational than peaches = scary.

To wrap it up...

I know a couple of people with odd phobias, one of a foodstuff and another of an everyday harmless object. Both of these people are otherwise completely well-adjusted human beings. They are college graduates with jobs, families, friends etc, and perfectly intelligent, sane and normal in every other way.

If each of us looked hard at it, we would probably all of us find that many of the things we personally find scary are really not all that rational to be afraid of at all. For example, is it any more fundamentally rational to be afraid of asking someone out than to be afraid of peaches?

Knowing it's not rational will not stop anyone being scared of it of course. :)

aww ((((LON)))) thanks for the visit! I have no insight to your question, none rational anyways. If it is sex related somehow, perhaps the cherry should be included.