In today’s world, no one should go hungry
Improved food preservation through technology
More effective food preservation systems, including technologies for processing and storage, are essential for balancing supply and demand, evening out the shocks of extreme weather events, balancing under/overproduction cycles, and improving market delivery. New technologies also extend the shelf life of food – guaranteeing safety without affecting taste, appearance or nutritional properties. Most of these solutions rely on metals and minerals for their key components.
Heating technologies can be divided into thermal (microwave or ohmic heating) and non-thermal: primarily High Pressure Processing (HPP) or Pulsed Electric Field (PEF). The first HPP equipment – introduced in 1899 to pasteurise raw milk – comprised tubular containers made of tin, lead and steel, pressured using a steel piston. Without these metals, this machine could not be built – even today, where HPP is used to inactivate spoilage microorganisms in packaged foods, extending shelf life. HPP also preserves solid foods, and can be used for other processing procedures, such as removing meat from shellfish. Its usage continues to grow, mainly due to health-conscious consumers demanding organic or naturally-treated convenience food. A PEF system, meanwhile, comprises three basic components: a high voltage pulse generator, a treatment chamber and a control system for monitoring the process parameters. The treatment chamber, which is the heart of the machine, usually consists of two electrodes – built from stainless steel, carbon, gold, platinum and metal oxides.
During the irradiation process, food is exposed to a carefully measured amount of ionising radiation. This improves food safety and extends shelf life by reducing or eliminating microorganisms and insects, preventing the germination or sprouting of vegetables, as well as slowing down the ripening and ageing of fruit. Currently, there are around 200 large-scale irradiators in 40 countries around the world, including developing countries such as Ghana and Bangladesh. At an irradiation facility, the radiation source is contained in a stainless steel casing. The casings are in turn contained in a lead-lined chamber. Packaged food travels on a conveyor belt between concrete walls, into and through a chamber, where it is exposed to radiation. This process would not be possible without metals and minerals, including cobalt, iron, chromium, lead, and lime.
Freezing and refrigeration are key methods of preservation throughout the food chain, from producers and freight companies to consumers. However, its usage is highly related to any area’s level of economic development, including reliable energy access. While 99% of households in developed countries own a fridge, in India it is only one in four. Refrigeration systems are either closed mechanical systems or open cryogenic systems. The main elements of the former are a condenser, compressor, evaporator and expansion valve, as well as refrigerants circulated within this system, most commonly hydrochlorofluorocarbon (HCFC) and ammonia. A cryogenic system comprises two major components: the compressor package, which compresses refrigerant and removes heat from the system, and the cold head, which takes refrigerant to cool it down to cryogenic temperatures. In general, a refrigerator is built from a variety of metals and minerals, including hematite, chromite (stainless steel), galena, copper, cinnabar, and pentlandite.
Hi-tech solutions are not always needed to reduce hunger. In Bangladesh, for example, the World Bank financed simple silos which can store grain for up to three years. The silos are flat-bottomed constructions which can be erected quickly and easily moved to different places. Another advantage is that they occupy much less space than conventional concrete warehousing. The silos are equipped with computerised humidity and temperature controls, helping retain the nutritional quality of food. The project is particularly important in increasing the grain reserve available to households to meet post-disaster needs. The silos in question are completely waterproof, weather-resistant, and have a long life thanks to the resilience of their construction materials, primarily stainless steel and aluminium.
Effective packaging of food is particularly important where a reliable power supply for freezing is not available, which is often the case in lower-income countries. Packaging can be made from multiple materials, including glass, plastics, wood, paper, or metal (aluminium or steel). The global market for metal packaging is projected to reach 135.69bn USD by 2020, with an annual growth rate of 3.0% from 2015 to 2020. With regards to sustainability, metals are called permanent materials, recycled again and again without changing their physical properties. Moreover, metal packaging can be used in a variety of sizes, from a small tomato can to a steel drum for bulk tomato transport. Metal elements also complement other kinds of packaging (e.g. a metal vacuum closure for a glass jar), while packaging machinery is mostly made from metals. Minerals are also crucial to the packaging industry; for example, silica – a compound of several minerals – is indispensable for glass production.