Bags and Pouches
A Packaging Primer - Pouches and Bags for HPP
How bags and pouches containing meats, soups, and more can be used for HPP
Flexible, sealed polymer-based packages that can be used for liquid, paste
or solid products. Used for retail and food-service/processor packs.
Depending on channel, decoration ranges from sophisticated printed
structures to post applied labels.
Typical HPP Product Uses:
Fruits & vegetables
• Seafood, including marinated fish & ready to eat (RTE) meals.
• Meat, including cold cuts, whole and sliced ham, raw and
marinated portions, ground meats & sausages.
*Also including RTE meals.
• Juices & beverages in single serve pouches & bulk bags for
• Baby food.
• Pet food.
• Wet salads & dips, especially for food service.
• Dairy products, including cheese & milk.
• Guacamole & salsa for retail and food service.
• RTE multicomponent foods, such as enchiladas & lasagna.
• Intermediates for combining with other components to make final products.
• Fabricated from polymer films ranging from mono-layer to more
typical coextruded or laminated structures for increased barrier,
toughness and material efficiency.
• Variety of shapes and seal formats, depending on product, type of
distribution and use.
• With proper material selection, capable of use in all food
preservative approaches, from frozen through shelf stable retort.
• Can be pre-made and filled on a separate machine or made inline
on form-fill-seal packaging machines.
• Well suited for HPP due to flexibility of structure and ability to
adjust to headspace volume changes during processing.
• Location of decoration can vary from labels to printed films; in
some cases secondary packages such as printed paperboard
sleeves or cartons carry the flexible package to the point of sale and home with the consumer.
Major Styles & Fabrication Methods:
• Three-side sealed - Made from a single web of material, this style
has one folded edge (with one or more folds, the latter forming
gussets) and three sealed edges, the edge opposite the fold is
sealed after product filling. Separation of adjacent pouches can
occur before or after filling.
• Four-side sealed - Made from two webs of materials, all edges of
the pouch are sealed.
• Back seal pouch - Made from a single web of material, which is
first formed into a tube by sealing the edges. After product filling
(horizontal for single items, vertical for liquid or multiple-piece
products), cross seals separate individual pouches, which are then
separated by cross-cutting.
• Fitments - Separate injection molded spouts, closures or other
dispensing and resealing elements; can be heat sealed at an open
end of a pouch prior to filling, or for bulk bags sealed into an
opening die cut into a wall prior to filling.
Print Surface - LDPE & variants (LLDPE or copolymers), BOPET,
• Heat Resistance - BOPET, BOPP, HDPE, polyamide.
• Bulk, Stiffness, Strength - LDPE & variants, HDPE, polyamide.
• Barrier - EVOH, Nylon, metalized films, PVdC & other coated films.
• Heat Seal - LDPE & variants, especially copolymers, also
ionomers for hard to seal through seal area contamination.
NOTE - Structures containing paper layers are not currently suitable for
HPP due to extreme moisture penetration during processing.
Special Design Considerations:
• Wide, strong seals essential to prevent leaking, special care to
ensure even pressures across seal areas to avoid weak spots, also
ensure compatibility of sealant layer with expect amount and type
of product contamination in seal area, especially in VFFS
• Special care required for sealing fitments to pouch opening or
• Zipper opening/re-close features should be isolated from direct
connection to the external environment by a heat seal, as alone
they will not likely be either liquid or gas tight at the processing
• Fitments must independently be designed for pressure exposure
to ensure no ingress of processing water or leakage of product
during compression or decompression.
• Pre-HPP process pressure sensitive or glue-applied labels should
avoid water-absorbing materials, be well adhered over entire label
surface to avoid water incursion between label and pouch
sidewall, and undergo any reversible sidewall distortion without
• Test post-HPP applied labels or coding to ensure proper adhesion
and and/or smooth lay on pouch surface at the application
temperature and humidity conditions.