Lesson 26 : Food packaging material – potential contaminants from food packaging material
These materials have been developed over the last 200-300 years and are the main types of packaging used by small-scale food processors.
Paper and cardboard
Different types of paper are used to wrap foods: ’sulphate' paper is strong and used for single- or multi-walled paper sacks for flour, sugar, fruits and vegetables; 'Sulphite' paper is lighter and weaker and is used for grocery bags and sweet wrappers, as an inner liner for plastic biscuit wrappers and laminated with plastic films. Greaseproof paper is sulphite paper made resistant to oils and fats, and used to wrap meat and dairy products.
‘Glassine’ is a greaseproof sulphite paper that is given a high gloss to make it resistant to water when dry, but it loses its resistance once it becomes wet. Tissue paper is a soft paper used for example to protect fruits against dust and bruising.
Papers are also treated with wax to provide a moisture barrier and allow the paper to be heat sealed.Wax coatings are easily damaged and the wax is therefore laminated between layers of paper and/or polyethylene when used for bread wrappers and inner liners for cereal cartons.
Paperboard’ is a term that includes boxboard, chipboard and corrugated or solid fiberboards. Typically, paperboard has the following structure:
A top layer of white material to give surface strength and printability.
Middle layers of grey/brown lower grade material.
An under-layer of white material to stop the color of the middle layer showing through.
A back layer if strength or printability are required.
All layers are glued together with adhesive.
White board is suitable for contact with foods and is often coated with wax or laminated with plastic to make it heat sealable. It is used for ice cream, chocolate and frozen food cartons.Chipboard is made from recycled paper and is used for example as the outer cartons for tea or cereals but not in contact with foods. It may be lined with white board to improve the appearance and strength.Other types include molded paperboard trays for eggs, fruit, meat or fish or for egg cartons.
Small paperboard tubs or cans are used for snack foods, confectionery, nuts, salt, cocoa powder and spices.