This article is from the Food Science FAQ, email@example.com (Paul E. J. King) with numerous contributions by others.
The packaging material has both to preserve the food and to
protect it from deterioration, outside contamination or damage during
distribution and storage; and the packaging material in direct
contact with a food must not itself harm, or be harmed by, the food.
The packaging material for a particular food must therefore be
carefully selected with these considerations in mind. Most countries
have developed strict controls, based on extensive testing, for the
use of "food contact" materials; and these help to ensure that a
correct choice is made.