Garlic and Shallots -- A Chemical Reaction?

[The Padre]

OK, this is my first post to DiscussCooking.com, but a question from a friend this morning got me searching for a food discussion site -- perhaps this is the place! Here's the scenario...
"A strange thing happened yesterday that has never happened to me before and I was wondering if you had a clue as to why. I had prechopped the garlic I was going to use for the entree and put it into a glass dish. I have done this many times before with no adverse affects. I had also pre chopped the shallots so I set the dish of garlic on top of the shallots and covered both with plastic wrap. The surprise came when I went to add the garlic as I was cooking the entree only to find out that it had turned a lovely shade of green!!!! Bright green! Almost an aqua green!!!! Any clue as to why? It wasn't touching the shallot, plus they are from the same family anyway."

Looking forward to hearing from y'all!

 

[GB]

Welcome to the site! I am sure someone here will have an answer for you. I really don't know, but I will throw out a question just to get the ball rolling. You said you had the the containers stacked. Could there have been something on the bottom of one of the containers (cleaning solution or something) that could have caused a reaction? I really don't think this is the answer, but I am just throwing it out there.

I am going to move this to the General Cooking Questions forum as it fits better there and will probably get a better response that way.

 

[The Padre]

Thanks for your advice, GB!

Knowing this chef, I'd say that the dish(es) were impeccibly clean. I know I would volunteer to eat off her floor, she's that tidy and fussy. Also a well-experienced cook. I'm guessing a chemical/gas reaction. I know one doesn't store onion-family vegs with potatoes (or, once I found out, bananas) since the gas ripenes-then-rots them, but... within the same family?

Hmmmm...

 

[Andy M.]

I've heard of garlic changing color to blue or green before. I've heard it's not a harmful change unless the color change bruises you sensibilities.

Perhaps there's someone in Ft. Worth who can offer a specific answer...

 

[jennyema]

Did you add an acid? Garlic turns bluish greeen sometime when exposed to an acidic ingredient. Also with exposure to copper.

See here:http://www.foodnetwork.com/food/ck_culinary_qa/article/0,1971,FOOD_9796_1702231,00.html

And here: http://www.google.com/search?hl=en&q=blue+garlic&btnG=Google+Search

 

[Claire]

Oh, strange. I've never seen this, but then I'm not as good at mis en place as I should be ... I think the gasses reacted somehow and I'm hoping someone comes up with an explanation.

 

[luvs]

i make pickled garlic, and it always turns bright blue. i read up on it, and it has something to do with the sulphur compounds in it. it's perfectly safe to eat. the acids react with the compounds, is all.

 

[mitch_the_chef]

http://forum.epicurean.com/webbbs/config.pl?read=7248

Read this. Maybe, you got some water, butter, or lemon juice on the garlic. I was thinking that maybe you could have cut a lemon in half before chopping the garlic and it turned green when you had your back turned. This doesn't really have much to do with cleanliness because lemon juice (I think) disinfects. Also I don't know anyone who cleans of thier cutting board after doing something as small as cutting a lemon. A possibility?