Apparently some overseas fruit is ripened with Carbide using a method that is dangerous to human health.

I think I would be wary of any tinned fruit (eg; Mangoes) from overseas too after reading this;

http://www.ehow.com/info_8617953_effect-carbide-fruit-ripening.html 

A google will bring up other links on the subject, I can't see anything on the hoax sites about it but feel free to check.