A recent post on Delphi has prompted me to write this cautionary article.
The Moon Sand (sold by Toys R Us) may or may not be problematic from a corn standpoint, but its best to be cautious.
The mother who posted describes severe allergic reactions to the Moon Sand in all three of her daughters. The two youngest daughters are both allergic to corn. The allergies of the oldest are currently unknown.
Her youngest (2 yr old) touched the sand for under 2 minutes before reacting. Her middle child touched it for 15 minutes, then showed signs of allergic reaction (behaviors known to be associated with allergic reactions in this child) which resulted in a mild anaphylaxis 4 hours later. The time frame of reactivity for the oldest was not given.
Please use caution if you're thinking of using this product with allergenic children.