This is an update of the article prepared by the European Committee of Sugar Manufacturers (CEFS) for the 3rd edition of the “Encyclopaedia of Occupational Health and Safety”.
The process of producing sugar from beets consists of many steps, which have been improved continuously throughout the more than century-old history of the sugar-beet industry. Sugar-beet processing facilities have become modernized and use current technology as well as current safety measures. Workers are now trained in using modern and sophisticated equipment.
The sugar content of the beets ranges from 15 to 18%. They are first cleaned in a beet washer. They are then cut in beet slicers and the “cossettes” thus obtained are conveyed via a scalder into the diffuser, where most of the sugar contained in the beets is extracted in hot water. The desugarized cossettes, called “pulps”, are pressed mechanically and dried, mostly by heat. The pulps contain many nutrients and are used as animal feed.
The raw juice obtained in the diffuser, in addition to sugar, also contains non-sugar impurities which are precipitated (by adding lime and carbon dioxide) and then filtered. The raw juice thus becomes thin juice, with a sugar content of 12 to 14%. The thin juice is concentrated in evaporators to 65 to 70% dry matter. This thick juice is boiled in a vacuum pan at a temperature of about 70 °C until crystals form. This is then discharged into mixers, and the liquid surrounding the crystals is spun off. The low syrup thus separated from the sugar crystals still contains sugar which can be crystallized. The desugaring process is continued until it is no longer economical. Molasses is the syrup left after the last crystallization.
After drying and cooling, the sugar is stored in silos, where it can be kept indefinitely if adequately air conditioned and moisture controlled.
The molasses contains approximately 60% sugar and, together with the non-sugar impurities, constitutes valuable animal feed as well as an ideal culture medium for many micro-organisms. For animal feed, part of the molasses is added to the sugar-exhausted pulps before they are dried. Molasses is also used for the production of yeast and alcohol.
With the help of other micro-organisms, other products can be made, such as lactic acid, an important raw material for the food and pharmaceutical industries, or citric acid, which the food industry needs in great quantities. Molasses is also used in the production of antibiotics such as penicillin and streptomycin, and also of sodium glutamate.
In the highly mechanized sugar-beet industry, the beet is transformed into sugar during what is known as the “campaign”. The campaign lasts from 3 to 4 months, during which time the processing plants operate continuously. Personnel work in rotating shifts around the clock. Additional workers may be added temporarily during peak periods. Upon completion of the beet processing, repairs, maintenance and updates are done in the facilities.
Hazards and Their Prevention
Sugar beet processing does not produce or involve working with toxic gases or airborne dusts. Parts of the processing facility may be extremely noisy. In areas where the noise levels cannot be brought down to the threshold limits, hearing protection needs to be provided and a hearing conservation programme instituted. However, for the most part, occupationally related illnesses are rare in the sugar-beet processing plants. This is partially due to the fact that the campaign is only of 3 to 4 months duration per year.
As in most food industries, contact dermatitis and skin allergies from cleaning agents used to clean vats and equipment can be a problem, requiring gloves. When entering vats for cleaning or other reasons, confined space procedures should be in effect.
Care must be taken when entering silos of stored granular sugar, due to the risk of engulfment, a hazard similar to that of grain silos. (See the article “Grain, grain milling and grain-based consumer products” in this chapter for more detailed recommendations.)
Burns from steam lines and hot water are a concern. Proper maintenance, PPE and employee training can help prevent this type of injury.
Mechanization and automation in the sugar-beet industry minimize the risk of ergonomic disorders.
Machinery must be regularly checked and routinely maintained and repaired as required. Safety guards and mechanisms must be kept in place. Employees should have access to protective equipment and devices. Employees should be required to participate in safety training.