HEALTH AND SAFETY CONSIDERATIONS IN PRINTING

105Industry wants to be protected against extreme requirements in the case of a smallamount of food in contact with an extremely large packaging surface area. Theywould argue that foods packed in small portions are usually consumed in smallamounts. These are reasons to express SMLs and the OML as limit per food contactsurface area. The European legislation assumes that 1 kg of food is exposed to 6 dm 2surface area of packing material, i.e. that it forms a 1 kg cube. Accordingly, the OMLof 60 mg/kg is equivalent to 10 mg/dm 2 . This is also an extreme assumption: while itis a good approximation for 1 kg packs of flour or rice, for example, for most foodsthe contact surface area is substantially larger and, therefore, the tolerated migrationin terms of concentration is higher. European legislation specifies that OM and SMshould be determined as concentrations in food if the packaging material can befilled (known surface area/volume ratio) and has a volume between 0.5 and 10 l(Directive 2002/ 72, Article 2). For small containers, the limits apply as migrationper surface area. If the packaging material cannot be filled, i.e. if it is, for example, asheet or film, the ratio of contact surface area/volume is unknown and limits alwaysapply as migration per unit surface area in food contact, i.e. as mg/dm 2 . This meansthat for the majority of packs the limits apply as amounts per contact surface areaand, thus, the conversion factor of 6 dm 2 /kg is used—which is why this conversionfactor is so important. It also means that SMLs are not really based on theconsumption of 1 kg of food, but on the amount of food which is in contact with 6dm 2 , which is mostly far less than 1 kg in real life. (Grob, Pfenninger, Pohl, Laso,Imhof, Rieger & 2005).5.2.3 Migration TestThe basis is council directive 82/711/EEC and the subsequent amended directiveslaying down the basic rules necessary for testing migration of constituents of plasticmaterials and articles intended to come into contact with foodstuffs. These directiveslay down basic rules for migration tests conducted to determine the overall migrationand the specific migration of individual substances using food simulants and underdefined test conditions. Since it is not always possible to use real foodstuffs whentesting materials that come into contact with foodstuffs, food simulants are used. By