From farm to table

Paying less for good bread

By Morand Fachot

Industrial automation mainly evokes images of assembly lines where machines and robots put together, pack and dispatch semi-finished products or manufactured goods. Yet, one sector that rarely comes to mind, although it has experienced an unprecedented degree of automation and has a direct impact on the lives of hundreds of millions, is the food-processing industry. A striking example of this is provided by the bakery sector.

Industrial bread
From silo to shelves in 24 hours...

Safer and more affordable food

Even if there are large disparities between countries, it is true overall that the cost of food as a percentage of the total household budget is decreasing consistently. One of the key reasons is a growing trend for the massive automation in transforming produce into consumer-ready food products. Large scale automation in the food-processing industry has helped reduce waste and increase food safety all the way from the farm to consumers’ tables.

This trend, obvious in developed economies, is also now being observed in emerging economies. Automation in all parts of the food-processing industry relies mainly on the introduction of electrical and electronic systems. International Standards for automation are developed by IEC Technical Committee (TC) 65: Industrial-process measurement, control and automation and its Subcommittees (SCs).

All about bread

Bread plays a crucial role in the diet of many people across the world. In some countries it is the staple food and makes up a sizeable share of household food expenditures. An increase in the price of bread resulting from cuts in subsidies or a rise in the price of cereals can provoke unrest. This was the case in the 2007 “tortilla riots” that followed the introduction of higher corn prices in Mexico, and in subsequent bread riots in many other regions of the world.

By contrast, the share of household income allocated to bread consumption in most industrialized countries has kept falling, and now represents just a fraction of overall expenditure on food. This is a result of massive automation throughout the whole production chain.

From grain to flour

With cereal crops forming the basis of the diet of 3,5 billion people around the world, bread is probably the most widespread food staple. Agricultural mechanization together with genetic selection has resulted in higher yields in grain production. Once harvested, grain must be stored for a certain period before being processed. Grains of all kinds are kept in special silos, an operation that presents certain safety risks as grain dusts make up an inflammable and potentially explosive mix. To prevent this hazard, electrical installations in grain storage facilities must meet stringent safety requirements to prevent such explosions. IEC TC 31: Equipment for explosive atmospheres, and its SCs, develop International Standards for the explosion-proof so-called Ex electrical installations fitted in grain storage facilities.

The next step in the bread-making process is the production of flour. The quality of the bread and other bakery products depends to a large extent on the quality of the flour, which requires specialist machines for its production. These machines include equipment destined to clean grain, to mill it and to sort the end products. Most of these machines are powered by electricity.

Wide range of machines

Cleaning grain is a complex process that requires drum magnets and drum sieves designed to remove ferrous items from granular or mealy products as well as straw fragments, paper, pieces of wood, or maize cobs from fine- and coarse-grained bulk materials. Combi-cleaners and separators are used to remove all the material that deviates from the size of the grain kernel. In the final step of the cleaning process, an aspirator eliminates all low-density particles such as dust and husks. Once grain is cleaned it can be milled.

Milling of grain is carried out using mainly electrically operated rotating steel rollers and sieves to separate bran and germ from the endosperm, which will end up as white flour through gradual reduction. A wider choice of flours, including wholemeal, can be produced by mixing back bran and germ into white flour.

All machines used in cleaning and milling grain and in sorting out end products rely on electricity, most of them on rotating machinery for which International Standards are developed by IEC TC 2.

The whole procedure is highly automated, allowing mills to process vast quantities of grain around the clock. A single UK milling company transforms 6 000 tonnes of wheat into flour every day. This flour is then distributed either in bags or in bulk to both small-scale and industrial bakeries. Just as with grain storage in silos, the bulk transfer of flour in lorries from the mills requires explosion-proof equipment and special measures such as earthing of vehicles to prevent the build-up of potentially dangerous static electricity.

From flour to the loaf on the table

The transformation of flour into bread is an equally complex process that also requires a wide range of machines. The difference between industrial and small-scale bakeries is not only about the kind and quantity of bread they produce and the way it is distributed, but also the speed at which it is produced, and hence the range of equipment they both use.

Flour, water, yeast, salt and other ingredients are blended together using mixing machines; the flour is wetted evenly and immediately transformed into dough.

Once dough is ready, a process that is speeded up in industrial bakeries by submitting it to a succession of quick rises in temperatures followed by cooling periods, it is cut into smaller portions and baked.

Heating and baking equipment for the final baking processes uses a variety of sources of heat such as direct and indirect resistance heating, microwave heating, or infrared radiation heating. IEC TC 27: Industrial electroheating and electromagnetic processing, develops International Standards for this type of equipment.

Once bread is baked, the final stage in industrial bakeries consists in sorting, packing and dispatching products to the shops. This process is also highly automated, with equipment used in this phase including conveyor belts, automated packing machines and forklifts. International Standards for all components and systems for this equipment are developed by a number of IEC TCs. The highly-automated structure of industrial bakeries allows them to produce loaves in under four hours between flour delivery and packing and to ensure they are on shelves within 24 hours – all this at very low cost to consumers.

More than just bread

Automation in the food-processing industry extends well beyond the baking industry to include many other sectors such as the dairy industry, which makes extensive use of automated machinery from the cow-shed to the bottle of milk or to other dairy products.

Automatic milking systems, first introduced in the 1990s, are now in widespread use in dairy farms. They allow higher milk production as cows are now able to enter automated milking units by themselves when they feel the need to be milked.

Following milk collection from farms by wholesale distributors, milk is sent to large plants where it is processed, packaged and dispatched using automated installations that allow fresh milk to be on shops’ shelves within a day of having left the farm.

Automation in the food-processing industry has given a greater number of people wider access to good-quality, safe products at an ever lower relative price. The IEC is playing an important part in this process by developing International Standards for a wide range of systems and equipment used throughout the whole industry.

Gallery
Port Giles silos Scott Davis Grain silos are explosive-risk installations (Photo: Scott Davis)
Roller mill floor Walzenstuhlboden 22958 Grain is gradually transformed into flour using roller and other mills (Photo Bühler AG)
Industrial bread From silo to shelves in 24 hours...