Food packaging technology: Part 2

Food packaging technology: Part 2 has present the content: plastics in food packaging; paper and paperboard packaging; active packaging; modified atmosphere packaging; determination of headspace gas composition; measurement of transmission rate and permeability in packaging films; effect of the gaseous environment on the activity of bacteria, yeasts and moulds; . | 7 Plastics in food packaging Mark J. Kirwan and John W. Strawbridge Introduction Definition and background The most recent EU Directive relating to plastic materials and articles intended to come into contact with foodstuffs reference 2001 62 EC defines plastics as being organic macromolecular compounds obtained by polymerisation polycondensation polyaddition or any similar process from molecules with a lower molecular weight or by chemical alteration of natural macromolecular compounds . Plastics are widely used for packaging materials and in the construction of food processing plant and equipment because they are flowable and mouldable under certain conditions to make sheets shapes and structures they are generally chemically inert though not necessarily impermeable they are cost effective in meeting market needs they are lightweight they provide choices in respect of transparency colour heat sealing heat resistance and barrier. Referring again to the Directive molecules with a lower molecular weight are known as monomers and the macromolecular compounds are known as poly- mers a word derived from Greek meaning many parts. The first plastics were derived from natural raw materials and subsequently in the first half of the 20th century from coal oil and natural gas. The most widely used plastic today polyethylene was invented in 1933 it was used in packaging from the late 1940s onwards in the form of squeeze bottles crates for fish replacing wooden boxes and film and extrusion coatings on paper- board for milk cartons. In Europe nearly 40 of all plastics is used in the packaging sector and packaging is the largest sector of plastics usage Association of Plastics Manu- facturers in Europe APME . About 50 of Europe s food is packed in plastic packaging British Plastics Federation BPF . Plastics have properties of strength and toughness. For example polyethylene terephthalate PET film has a mechanical strength similar to that of iron but PLASTICS IN FOOD .

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