Packaging of Dairy Products

Lesson 15 F

15.21 Retortable Pouches

• A typical laminate for retortable pouch is 0.0005 polyester / 0.00035 foil / 0.003 polypropylene, with the outer ply designated first as is customary for pouch material.

• Filled pouches are sterilized at 115-1210 C, with overriding air pressure of ~ 2 kg/cm2 to prevent bursting.

• Pouch material that will not delaminate at these temperatures must be selected, and the seals should withstand a tensile test of 0.08 kg/m of width, internal pressure of 1 kg/cm2 for 30 s, pinhole strength of 0.6 kg and a drop test of 1.22 m.

15.22 Multilayer Collaspsible Tubes (MLCT)

• The collapsible tube has traditionally been made of soft metal, tin, lead, tin-lead and in recent years aluminum.

• One end of the tube is a threaded dispensing nozzle which can be closed by a screw cap closure.

• The entire tube is formed by impact extrusion from a slug of metal, and then it is trimmed, threaded and annealed.

• Exteriors are decorated by roller coating and offset printing.

• Interiors may be lined by dipping, flushing or spraying prior to exterior coatings.

• Linings may be waxes or vinlys, phenolic or epoxy resins.

• Product is filled through the open bottom which is then crimped or sealed shut.

• In use, the closure is removed, the interior seal (if present) is punctured and product is dispensed through the nozzle by squeezing the tube.

• Tubes are marketed on cards, in blister packs or in folded cartons.

• Blow-molded plastic tubes are now being used for some products. Their main disadvantage is lack of dead - fold. They tend to spring back when squeezed making total dispensing of the product difficult.

• Tubes are best for packaging thick liquids or thin pasty solids.

• It is used for packaging of process cheese spread/ fruit jams, fat spread and ketch-ups.