It's just cornstarch. Same reason you should never use pre-shredded cheese on a pizza, the cornstarch burns faster than the cheese does.
Because it's soluble in water, you can (and I have) washed pre-shredded cheese in a colander and dried it on a kitchen towel when it was all I had on hand, and it turned out fine.
Because it's soluble in water, you can (and I have) washed pre-shredded cheese in a colander and dried it on a kitchen towel when it was all I had on hand, and it turned out fine.