Toxic metals in foil take-out containers?

I had a weird experience last night eating take-out lasagna from a local restaurant. The lasagna had a strong metallic taste. I already knew that tomato sauce and other acidic foods react with and dissolve aluminum (http://www.straightdope.com/columns/read/111/why-does-ketchup-dissolve-aluminum-foil). The weird experience was that, while eating, I experienced a pain like a brief electric shock in one of my fillings! I have to assume that the aluminum ions in the acidic tomato sauce in my mouth were briefly concentrated enough in that one spot to produce the well-known “biting down on foil” effect (described in the same column).

The electric shock initiated the chain of thought that leads to my question: Like everything else in America, many, many of our disposable aluminum foil food containers come from China. We know that Chinese industry, not to put too fine a point on it, sometimes has difficulty with quality control. (Melamine in dog and baby food; “Aqua Dots” toys made with GHB precursor; etc.) My question is this: Are imported food containers inspected to ensure that what claims to be an aluminum foil tray isn’t actually contaminated with mercury, cadmium, or the other toxic metal of your choice?

That doesn’t make sense.
Mercury & cadmium are both more expensive than aluminum. All the Chinese scandals so far have resulted from them trying to substitute a cheaper counterfeit for the genuine product. Why would they use a more expensive one?

Do you have any reason to believe that this is true, or are you just making an assumption here? Because a little quick search on the web indicates that many such containers are made by Handi-foil Corporation and Reynolds Metals. Both are American companies.

The following information regarding production of aluminum is from Wikipedia:

*In 2005, the People’s Republic of China was the top producer of aluminium with almost a one-fifth world share, followed by Russia, Canada, and the USA, reports the British Geological Survey. *

While China leads in terms of production (low electric energy costs) most of their ore comes from Australia. The only raw materials in the electrochemical process are the ore (aluminum oxides) and cryolite (sodium aluminum fluoride with some calcium which is now synthetically made). The introduction of other toxic metals is unlikely.

Approximately 40% of consumer aluminum is recycled; however, once again the process does not easily lend itself to introduction of toxic metals.

Maybe the cook’s gold chain broke and fell into the marinara pot that night.