What is so holy about macaroni?

Dear Adam, 

While my colleagues were too busy causing damage to other people's
keyboard and wasting their coffee, I set on a quest for the holy
macaroni.

Well, Macaroni is only one in a series of holy objects, used for exclamation: 
- holy cow
- Holy meckerel
- holy s**t
- holy moses
- holy moley/moly 
- holy Toledo

It is rather new in comparison to the others: 
Ken Greenwald writes, "Macaronis(or ies) have holes in them (they are
tubular), so this is probably a play on the homophones (homonyms)
holey and holy. It has the same meaning as holy cow, etc.

Here?s a little more info with some dates, but with no new inforamtion
on derivations.

American Heritage Dictionary of Idioms:

holy cow, holy mackerel or Moses or moly or smoke. An exclamation of
surprise, astonishment, delight, or dismay, as in Holy cow, I forgot
the wine, or Holy mackerel, you won! or Holy Moses, here comes the
teacher! or Holy smoke, I didn't know you were here too. The oldest of
these slangy expletives uses mackerel, dating from about 1800; the one
with Moses dates from about 1850 and cow from about 1920. None has any
literal significance, and moly is a neologism devised to rhyme with
?holy? and possibly a euphemism for ?Moses.? (SOURCE: Ken Greenwald,
"The Wordwizard Clubhouse - holy mackerel and other holies"
<http://www.wordwizard.com/clubhouse/founddiscuss1.asp?Num=2735>).

You could see more holies here: 
World Wide Words <http://www.quinion.com/words/qa/qa-hol1.htm> 
Re: Holy Phrases, Phrase Finder,
<http://phrases.shu.ac.uk/bulletin_board/19/messages/609.html>

Who sanctified it? 

Surprisingly, I didn't find reference in any reputable slang
dictionary. It requires, therefore, further research.

The Phrase Finder Bulletin Board participants actually trace the most
newest holies to Batman, who uses many "harmless" objects as types of
exclamations by Robin.

However, it might have been Homer (Simpson, not the guy from the
Iliad) who popularised it:
Urban Dictionary, "Holy Macaroni"
<http://www.urbandictionary.com/define.php?term=Holy+Macaroni>

I hope this answered your question. I like macaroni and this question
made me hungry. Please contact me if you need any clarifications on
this answer.

My search terms: the term, with "dictionary" "slang" etc.

Macaroni must be holy, because every time I eat it, I think "What a
friend I have in cheeses."

Pink,

My morning coffee just came out my nose. That's the best one I've heard all week.

Nenna-GA

Its a little known fact that on macaroni farms the holes come up first
and some weeks later the macaroni grows up around them. There you have
it - its a miracle!

tutuzdad-ga

I thought it was Holy Guacamole!

Emeril Lagasse says it's "Wholly Macaroni". Maybe we've all been wrong
all this time.

http://www.foodtv.com/food/show_em/episode/0,1976,FOOD_9959_16599,00.html

Gad, Pink.  I mean, gad.  I'm speechless.