A Correct Packaging Technology May Limit Food Waste

The waste of food supplies has reached an unacceptable level for a planet whose population is growing

by Giuseppe Giordano

About one third of the food resources produced each year in the world (equal to roughly 1.3 billion tons of food) is lost or wasted. The FAO has been saying this for some time, putting the blame almost equally on developing countries (about 670 million tons of food per year) and on countries with greater economic development (about 630 million tons per year). In the recent FAO document presented even at the Interpack 2017 packaging trade show, many interesting data concerning food waste may be found. The FAO study considers the loss of product which occurs between the field and the table. These are topped by the food waste data typical of rich countries. It is estimated that, every year and from the table onwards, consumers in rich countries waste almost the same amount of food (222 million tons) as the entire net food production of sub-Saharan Africa (230 million tons). Food loss (figure 1) occurs in the production, gathering and processing phases and is more relevant in developing countries because of the severely insufficient infrastructures and of the lack of materials and technology, for instance, for the local production of efficient packaging at acceptable costs. The waste of processed food, on the other hand, is an issue felt more often in industrialized countries, where operators and consumers throw away food still in perfect conditions which could very well be used. Even in this case the technologies which concern packaging, such as the possibility of closing with high efficiency the packaging after a partial consumption, may play a particularly active role. In developing countries, 40% of losses due to the unavailability of adequately strong and efficient packaging occur in the phase following gathering and during the processing of products. The FAO data allow to get into further details. For instance, 45% of fruit and vegetables are not used and here the difference in technology in treating the product is evident. The phase of processing which follows gathering presents a loss rate which is negligible in industrialized countries, but completely different in poorer countries.
Cereals show a high rate of deterioration prior to consumption even in countries such as India and China, where for years industrial policies have been developed to cut down on waste (figure 2).
Loss during gathering and storage converts to loss in income for small agricultural companies and higher final prices, which often are beyond the reach of local low-income populations. Loss and waste imply a huge wastage of such resources as water, land, energy and work, as well as a useless production of emissions. Figure 3 shows the amount of CO2 linked to the wasted food: if this could be summed up to form a value comparable to that of nations, it would turn out that the emission of carbon dioxide due to food waste would be third after the giants, China and USA, and larger than that of a country with more than a billion inhabitants such as India.

Transferring know-how to produce adequate packaging in developing countries
Considering only the issue of preserving the resources produces and distributed, in the relationship between the Western world and developing countries an agreement should be made between the holders of adequate technologies and potential users, to define a barrier level adequate for the protection of the resources. When choosing an adequate packaging, the capability of acting as a barrier is an important factor for the selection. Barrier properties include above all the permeability of materials to gases (such as oxygen nitrogen and carbon dioxide), water vapour and light. A second property which may be associated to the capability of acting as a barrier is linked to the mechanical resistance of the packaging, able, for instance, to fend back attacks by rodents and insects. Furthermore, barrier materials must resist to medium-high temperatures to allow heat sealing operations which will make the container airtight. It is also worth noting that the barrier effect is twofold. The barrier is not only instrumental in preventing access of aggressive agents from the outside but it also prevents the loss by leakage of characteristics of the product which are essential in determining its quality level, such as internal humidity, fragrance, granulometric consistency and so on.
Few words are as effective as the term “barrier”, in the packaging sector, in bringing to mind immediately aluminium sheets. Aluminium is the only meal technically and economically available for the production of packaging which can provide resistance against rodents during storage just as it can prevent contact of the product with outside humidity. At the same time, the barrier created by the sheet prevents quantitative and qualitative loss in fragrances and functional performances which determine perceived quality and market price. The most famous example of enhancement of the barrier capabilities of the aluminium sheets is provided by cartons for milk, fruit juice, wine and other beverages made using Tetra Pack®. Figure 4 shows the layer scheme of the material, It may be noted that the aluminium sheet, which is just over 6 micron in thickness, represents only 4% of the whole, but even though its percentage is so small, it is the main obstacle to the content’s deterioration.
It is interesting to highlight the reasons which enable the sheet to act as a barrier even though its thickness is so reduced. In order to understand this property, it is necessary to go back to the metallic structure which is not porous, unlike the structure of plastic which is made up of polymer chains entwined in different ways, the fibrous structure of paper or the porous warp and weft of fabric. The metal state is characterised at the solid state by the presence of a lattice of atoms placed at fixed positions and surrounded by a “cloud” of electrons. The various metals may have more or less compact crystal structures (figure 5). Aluminium has a cubic structure with centred faces which proves to be the most compact, that is, the most pliable.
Pliability is the property of a material which allows it to be deformed permanently following adequate pressure or collisions, without undergoing noticeable structural or mechanical resistance changes and without fractures. Regarding aluminium, the high pliability converts into the possibility of obtaining sheets which, although very thin, are equally compact and capable of creating high-barrier structures. Sheet technology, when it is limited to simple alloys which generically belong to the 1xxx,3xxx and 8xxx (AL-Fe-Si) families, offers the possibility of using a traditional cycle (DC road) of semi-continuous slab casting followed by hot rolling before the final cold phases, or of producing using continuous casting, basically skipping the hot rolling phase. The investment costs for a continuous casting plant are lower with respect to a traditional DC road plant. This explains the remarkable popularity of CC road technology, not just in less developed countries. Even in Italy, for instance, the number of CC twin roll plants for foil stock production has grown and currently more than ten castings of this type are being used.

Final considerations
By examining figure 6, which shows he growth of the world’s population according to the forecasts by the UNO’s 2017 World Population Prospects, crossed with the CRU 2012 estimate for global consumption of foil stock adding up to about 5.3 million tons (or 0.76 kg per head), as from 2018 merely keeping the per capita consumption constant would imply a demand of foil stock equal to roughly 5.75 million tons, with an average increase of 8.5% differentiated in the various regions. In 2030, the world’s population is expected to increase by about one billion individuals, The foil stock consumption, keeping constant the 2012 requirements, would grow by about 750,000 tons. These conservative data would keep as a reference scenario a waste of food resources equal to the present one. If the global increase in per capita foil stock consumption, which is not only welcome, but actually necessary given the increase in the population, were to reach 50% of the per capita consumption in Europe, that is, about 2.25 kg/year (source: EAFA, 2012), about 9 million more tons of aluminium would be globally necessary just for sheet production.