Plastics used in food packaging and the rôle of additives

Whilst paper and derived products still dominate packaging and large quantities of glass are still used in containers, the usage of plastics is significant, particularly for food packaging. Plastics are advantageous in providing good barrier properties in packages of low density (low weight) and high durability at low cost.Primary packaging of foodstuffs utilises film and containers principally; secondary packaging involves a wider variety of forms, including tote boxes and crates. In a cost-sensitive market, the commodity thermoplastics—polyolefins, poly(vinyl chloride) and styrene plastics—are widely employed in food packaging but there is considerable application of more expensive polymers in more advanced forms for special requirements.Satisfactory plastics packaging should not adversely affect the food in contact with it. Whilst pure high polymers might be expected to be inert, residual monomer, residues from polymerisation ancillaries, adventitious impurities and deliberate additives, all of lower molecular weight than the polymer, might be migratory and require particular consideration.