Packaging Considerations - Food Shelf Life Stability: Chemical, Biochemical, and Microbiological Changes - page 140

Product stability during distribution is also influenced by the maintenance of
package integrity. Vibration and impacts during shipping and handling may cause
flex cracking in plastic packages and failure in barrier materials, resulting in accel-
erated degradative reactions and increased exposure to off-flavor permeation. 14
SHELF LIFE TESTING AND PREDICTION
Packaging considerations are critical to shelf life testing: namely, to understand the
requirements of the product, to understand package alternatives, and then to select
suitable candidate packages. An understanding of the intrinsic and extrinsic stability
of a food product can have an important influence on packaging considerations for
shelf life. Misdirected food product, process, and packaging development comes
from not clearly recognizing and monitoring these different product stabilities during
shelf life tests. 4
Specific approaches and procedures for shelf life testing and prediction have
been described thoroughly by numerous authors. 1,4,5,44 In general, the key approach
to shelf life testing is to first identify the major failure modes or mechanisms for a
product. Shelf life prediction becomes very complex when a food system has several
modes of deterioration, which may each have its own temperature sensitivity. How-
ever, shelf life at any given temperature will be determined by that mechanism which
proceeds most rapidly and thus causes the shortest life. 45 Traditional approaches to
shelf life testing generally involve storage tests where products are maintained under
a set of controlled (specific temperature and relative humidity) or uncontrolled (i.e.,
warehouse) conditions. However, an overestimation of shelf life is likely when only
some of the conditions a product may encounter during distribution are taken into
account. Environmental conditions can also be accelerated by a known factor so that
the product deteriorates at a faster than normal rate. However, accelerated shelf life
conditions may also influence the barrier properties of packaging materials and
thereby introduce additional degradation reactions that do not occur under normal
storage conditions.
FUTURE DIRECTIONS
Efforts to improve food shelf life stability may be attempted through the introduction
of new food preservation technologies, including new packaging materials and
forms, but the predominant concern must always be that the resulting products do
not compromise consumer safety. 46 As illustrated in Figure 4.2 , successful manufac-
turing and packaging of high quality food products should be considered from a
systems approach, where knowledge of the properties of each component and inter-
actions among them is used to understand and predict the performance of the overall
system.
A food package will be designed to provide containment, protection, conve-
nience, and communication. However, using the systems approach, the performance
of this package must also be evaluated in terms of its compatibility with the pro-
cessing conditions applied for food quality preservation, which must be maintained