260 Chapter 10
polypropylene (PP), polyvinyl chloride
(PVC), and several other materials have
shrinking attributes. Shrink fi lms for cheese
packaging must have good shrink properties,
abuse resistance, and seal strength. They gen-
erally possess good water and gas barrier
attributes for protecting cheese from mold
growth, oxidative degradation, and
dehydration.
For packaging Swiss and other gas -
producing cheeses, differential permeability
fi lms are used. These allow CO 2 to escape the
package, while preventing oxygen from per-
meating into the package. This attribute pre-
vents formation of puffed packages due to
release of gases by cheese.
Films for use in thermoform machines
must be easily heat formed for molding into
cavities. Several other fi lms have been made
available to accommodate the special needs
of relatively unusual cheese varieties.
Basic fi lm requirements include suitability
of printing and no transfer of odors or off
fl avors to cheese. The fi lms must not contain
toxic monomers, plasticizers, and inks
capable of migrating into the food.
Sustainability attributes are beginning to
assume a great deal of importance as well.
The fi lm must adequately control the head
space environment of the packaged cheese to
prevent oxidative deterioration, dehydration,
and undesirable mold development. The head
space environment is infl uenced by the pack-
aging method used and characteristics related
to the particular cheese variety being pack-
aged. Seal integrity, selective barrier proper-
ties, and the ability to cling closely to the
cheese body are all variables that can be con-
trolled by selection of suitable fi lms.Packaging for Cheese Ripening
In general, the packaging requirements for
ripening blocks of cheese are similar to those
for retail portions. Historically, most cheeses
for ripening were packaged by bandaging
and dressing. Bandaging involved the appli-uses of thermoform - fi ll - seal machines with
polystyrene as the base cup material and alu-
minum foil lamination as the heat seal
closure.
Packaging Films
Several varieties of fi lms are available for
retail cheese packaging. These include a vast
array of structures based on aluminum foil,
polyethylene (PE), polyamide, polyester, and
paper. They can be used singly or in combi-
nation as laminated structures. They may be
purchased as preformed bags or roll stock.
Film developed specifi cally for use in cheese
packaging can be obtained from several
suppliers.
Basic Film Types
Most tight - wrapped methods use simple,
economical materials for fi lms, such as clear
plastic wrap — polyvinylidine chloride
(PVDC) material of good barrier characteris-
tics. Aluminum foil laminates also are used
for some tight - wrapped cheeses.
Gas fl ush and vacuum packaging systems
require laminates. The shortcomings of
single - material fi lms can be overcome by
combining two or more materials to form
laminated structures. The components of
laminated fi lms are chosen so that each con-
tributes functionality desirable to the total
system. For example, PVDC and nylon are
often used as components of laminates; they
provide excellent barrier and fl exural proper-
ties, respectively.
Packages used for gas fl ushing require
materials that must have good machine
ability, fl ex crack resistance, good barrier
characteristics, and heat sealability.
Shrink fi lms adhere closely to the cheese
surface when heated by hot air or by dipping
in hot water at 82 ° C to 93 ° C (180 ° F to
199 ° F). They are produced by orienting or
stretching the fi lm under controlled condi-
tions. PVDC, polyethylene (PE), polyester,