The work and concepts introduced in this study have formed a basis for improved package evaluation methods towards the next-generation of future fresh produce package design. Additionally, it is intended that the approaches presented in this thesis be adapted and applied to other fresh produce packaging systems within the agricultural engineering and postharvest research communities.
The multi-parameter approach used to evaluate carton performance packed loose and with trays now needs to be extended to cartons packed with other internal packaging types (e.g. liner bags, carry bags and clam-shells). This will enable packhouses to tailor packaging designs to the respective contents, which is often determined by the destination and expected conditions during transit. Additionally, similar to vent holes on the horizontal axis, improvements in vent holes along the vertical axis also need to be explored using a multi-parameter approach as presented in this thesis. Currently, this aspect has been largely overlooked and the potential for improvements was raised during RFC evaluations (vertical airflow).
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The work in this thesis also identified the need for a new performance parameter to quantify pallet stack stability. Pallet stacks are relatively tall structures that must resist tipping over when being handled by forklifts or during the swaying of a ship at sea. Stability is often improved using additional packaging materials or using more complex stacking patterns, which can negatively affect cooling performance. The incorporation of a stability performance parameter to future multi-parameter evaluations is therefore recommended.
Quantifications of carton moisture content and distributions under various desirable and undesirable conditions are needed, which can then be related to mechanical pallet stack failures in real world conditions. Additionally, more information is needed regarding the physics behind moisture transport in fibreboard and mechano- sorptive creep, particularly at ultra-high humidity conditions (98-100% RH), which is relevant to certain fresh produce types. Much has already been speculated in these areas, however, more reliable empirical relationships are needed at these conditions. The development of a refined experimental box compression test protocol is another critical issue identified in this thesis. A promising direction, is the inclusion of protocols that evaluate the effects of both static and dynamic loads. Future box compression tests should also include conditioning treatments that can replicate the high moisture content conditions found in the cold chain. Furthermore, another possibility for future conditioning protocols is to include long term compression forces to replicate the effects of creep (mechano-sorptive). Finally, inclusion of mechanical calculation to current CFD models and the use of improved finite element models is also expected to play an important role in future mechanical strength evaluations. Detailed quantification of spatio-temporal moisture contents will thus be an important resource to these approaches.
Lastly, future goals include the development of numerical tools to evaluate packaging systems at much larger scales, while still including details of the individual fruit and internal packaging. This includes cooling assessments in fully loaded holding areas (FAC, RFC and cold rooms). Additionally, further developments in finite element models are required, which include the effects of pallet stacking and environmental factors (handling damage, high humidity and mechano-sorptive creep).
This thesis therefore provides some foundations and direction for realizing these ambitious goals and has addressed many research questions raised by the horticultural industry. Significant progress was made towards the advancement and implementation of a multi-parameter evaluation approach that is applicable for packaging horticultural fresh produce. Furthermore, a strong case has been made for the introduction of a new and novel packaging system that facilitates enhanced RFC space utilisation, improved cooling efficiency and increased mechanical strength.
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