Process Overview

The making of the concentrate is the first step in the production of a carbonated soft drink. At the beginnings of the industry, in the nineteenth century, both concentrate and soft drink were manufactured in the same facility. Sometimes the concentrate was sold to the consumers, who would make their own soft drinks. As the carbonated soft drink business has grown, the concentrate and the soft drink manufacturing have become specialized. Today, a concentrate manufacturing plant sells its product to various bottling companies.

Concentrate plants are constantly optimizing their operation through systems automation. As the demand for concentrate increases, automation has allowed the manufacturer to satisfy the demand without expanding the size of the manufacturing plant. Packaging size has increased too. Early in the industry, 1/2-, 1- and 5-gallon containers were the most common. Today 40- and 50-gallon drums and even tank trucks with capacities of 3,000 to 4,000 gallons are used.

Operations in a concentrate manufacturing plant can be divided into five basic processes:

1. treating water
2. receiving raw materials
3. concentrate manufacturing
4. concentrate and additives filling
5. shipping finished products.

Each of these processes has safety hazards that must be evaluated and controlled. Water is a very important ingredient in the concentrate and it must have excellent quality. Each concentrate plant treats water until it reaches the desired quality and is free from micro-organisms. Water treatment is monitored during all stages.

When the plant receives the compounding ingredients, inspection, sampling and analysing of the ingredients in the quality-control department are begun. Only materials that have passed the tests will be used in the concentrate manufacturing process. Some of the raw materials are received in tank trucks and require special handling. Also, packaging material is received, evaluated and analysed in the same way as the raw materials.

During the manufacturing of concentrate, treated water and liquid and solid ingredients are pumped into stainless-steel tanks, where they are mixed, homogenized and/or extracted in accordance with the manufacturing instructions. The tanks have capacities of 50 gallons, 10,000 gallons and even more. These tanks are completely clean and sanitized at the time of mixing.

Once the concentrate is manufactured, the filling stage is started. All the products are piped into the filling room. Filling machines are strictly cleaned and sanitized before the filling process starts. Most of the filling machines are dedicated to specific container sizes. The product is kept inside pipes and tanks at times during the filling process in order to avoid contamination. Each container should be labelled with the product name and handling hazards (if necessary). Full containers are moved by conveyors to the packaging area. Containers are placed on pallets and wrapped in plastic or tied before they are stored. Besides the concentrates, additives to be used in the preparation of carbonated soft drinks are packed. Many of these additives are packed in plastic bags and placed in boxes.

Once at the warehouse, the products are divided and prepared to be sent to the different bottling companies. These products should be labelled following all government regulations. If products are going to another country, the product must be labelled in accordance with the other country’s labelling requirements.

Production of fruit juices

Fruit juices are made from a wide variety of fruits, including oranges and other citrus fruits, apples, grapes, cranberries, pineapples, mangoes and so forth. In many cases, various fruit juices are blended. Usually, the fruit is processed into a concentrate near where it is grown, then shipped to a fruit juice packager. Fruit juices can be sold as concentrates, frozen concentrates (especially orange juice) and as the diluted juice. Often sugar and preservatives are added.

Once received at the processing plant, the oranges are washed, graded to remove damaged fruit, separated according to size and sent to the juice extractors. There the oils are extracted from the peel, and then the juice extracted by crushing. The pulpy juice is screened to remove seeds and pulp, which often end up as cattle feed. If the orange juice is intended for sale as “not from concentrate”, it is then pasteurized. Otherwise the juice is sent to evaporators, which remove most of the water by heat and vacuum, then chilled, to produce the frozen, concentrated orange juice. This process also removes many oils and essences which are blended back into the concentrate before shipping to the juice packager.

The frozen concentrate is shipped to the packager in refrigerated trucks or tankers. Many dairies package orange juice using the same equipment used to package milk. (See the article “Dairy products industry” elsewhere in this volume.) The concentrate is diluted with filtered water, pasteurized and packaged under sterile conditions. Depending on the amount of water added, the final product can be cans of frozen orange juice concentrate or ready-to-serve orange juice.

Michael McCann

Hazard Prevention

Hazards in a concentrate manufacturing plant vary depending on the products manufactured and the size of the plant.

Concentrate plants have a low injury rate due to a high degree of automation and mechanized handling. Materials are handled by fork-lifts, and full containers are placed on pallets by automatic palletizers. Although, employees generally do not have to use excessive force to get the job done, lifting related injuries remain a concern. Major hazards include engines and equipment in motion, objects falling from overhead containers, energy hazards in repair and maintenance, confined space hazards in cleaning mixing tanks, noise, fork-lift accidents and hazardous chemical cleaning agents. See the article “Soft drink bottling and canning” for more information on hazards and precautions.

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In most established markets around the world, soft drinks now rank first among manufactured beverages, surpassing even milk and coffee in terms of per capita consumption.

Including ready-to-drink, packaged products and bulk mixes for fountain dispensing, soft drinks are available in almost every conceivable size and flavour and in virtually every channel of retail distribution. Complementing this universal availability, much of the soft drink category’s growth can be attributed to convenient packaging. As consumers have become increasingly mobile, they have opted for easier-to-carry packaged goods. With the advent of the aluminium can and, more recently, the resealable plastic bottle, soft drink packaging has become lighter and more portable.

Stringent quality-control standards and state-of-the-art water treatment processes also have afforded the soft drink industry a high degree of confidence regarding product purity. Moreover, the manufacturing or bottling plants that produce soft drinks have evolved into highly mechanized, efficient and spotlessly clean food-processing facilities.

As early as the 1960s, most bottlers were producing beverages through machinery that ran at 150 bottles per minute. As product demand has continued to skyrocket, soft drink manufacturers have shifted to faster machinery. Thanks to advances in production technology, filling lines now are able to run in excess of 1,200 containers per minute, with minimal downtime except for product or flavour changes. This highly automated environment has allowed soft drink manufacturers to reduce the number of employees required to operate the lines (see figure 1). Still, as production efficiencies have risen dramatically, plant safety has remained an ever-important consideration.

Figure 1. Control panel in an automated soft drink plant in Novosibirsk, Russia.

Soft drink bottling or manufacturing involves five major processes, each with its own safety issues that must be evaluated and controlled:

1. treating water
2. compounding ingredients
3. carbonating product
4. filling product
5.  packaging.

See figure 2.

Figure 2. Flow chart of basic bottling operations.

Soft drink manufacturing starts with water, which is treated and cleansed to meet exacting quality-control standards, usually exceeding the quality of the local water supply. This process is critical to achieving high product quality and consistent taste profiles.

As ingredients are being compounded, the treated water is piped into large, stainless-steel tanks. This is the stage at which various ingredients are added and mixed. Diet beverages are mixed with artificial, non-nutritive sweeteners such as aspartame or saccharin, whereas regularly sweetened drinks typically use liquid sugars like fructose or sucrose. It is during this stage of the production process that food colouring may be added. Flavoured, sparkling waters receive the desired flavouring at this stage, while plain waters are stored in the mixing tanks until the filling line calls for them. It is common for bottling companies to purchase concentrate from other firms.

In order for carbonation (absorption of carbon dioxide (CO₂)) to occur, soft drinks are cooled using large, ammonia-based refrigeration systems. This is what gives carbonated products their effervescence and texture. CO₂ is stored in a liquid state and piped into carbonation units as needed. This process can be manipulated to control the required rate of beverage absorption. Depending upon the product, soft drinks may contain from 15 to 75 psi of CO₂. Fruit-flavoured soft drinks tend to have less carbonation than colas or sparkling water. Once carbonated, the product is ready to be dispensed into bottles and cans.

The filling room usually is separated from the rest of the facility, protecting open product from any possible contaminants. Again, the highly automated filling operation requires a minimal number of personnel. See figure 3 . Filling room operators monitor the equipment for efficiency, adding bulk lids or caps to the capping operation as necessary. Empty bottles and cans are transported automatically to the filling machine via bulk material-handling equipment.

Figure 3. Soft drink canning line showing filling operations.

Stringent quality-control procedures are followed throughout the production process. Technicians measure many variables, including CO₂, sugar content and taste, to ensure that finished drinks meet required quality standards.

Packaging is the last stage prior to warehousing and delivery. This process also has become highly automated. Meeting various marketplace requirements, bottles or cans enter the packaging machinery and may be wrapped with cardboard to form cases or placed into reusable plastic trays or shells. The packaged products then enter a palletizing machine, which automatically stacks them onto pallets. (See figure 4.) Next, the loaded pallets are moved—typically via fork-lift—to a warehouse, where they are stored.

Figure 4. Eight-packs of 2-litre soft drink plastic bottles on the way to an automatic palletizer.

Hazard Prevention

Lifting-related injuries—especially to employees’ backs and shoulders—are not uncommon in the beverage business. While many technological advances have been made in material handling over the years, the industry continues to seek safer, more efficient ways to move heavy product.

Certainly, employees must be provided with the proper training on safe work practices. Injuries also can be minimized by limiting exposure to lifting through enhanced work-station design. Adjustable tables can be used to raise or lower material to waist level, for example, so that employees do not have to bend and lift as much. In this manner, most weight-related stress is transferred to a piece of equipment instead of the human body. All beverage manufacturers should implement ergonomics programmes that identify work-related hazards and minimize the risks—either through modification or by developing better equipment. A reasonable means to that end is job rotation, which reduces employee exposure to high-risk tasks.

The use of machine guarding is another critical component of safe beverage manufacturing. Equipment such as fillers and conveyors move at high speeds and, if left unguarded, could snag employee clothing or body parts, causing potentially severe injuries. Conveyors, pulleys, gears and spindles must have appropriate covers to prevent employee contact. Overhead conveyors can create an additional hazard of falling cases. Netting or wire-mesh screens should be installed to protect against this danger. Maintenance programmes should dictate that all guarding which is removed for repair be replaced as soon as repair work is completed.

Since wet conditions are prevalent in the filling room, adequate drainage is necessary to keep liquid from accumulating on nearby walkways. In order to avoid slip-and-fall injuries, proper efforts must be made to keep floors as dry as possible. While steel-toed shoes usually are not required in the filling room, slip-resistant soles are highly recommended. Shoes should be selected based on the slip coefficient of the sole. Additionally, all electrical equipment should be properly grounded and protected from any moisture. Employees must take precautions to dry the areas around equipment before any electrical work begins.

Good housekeeping practices and routine inspections also are beneficial in keeping the workplace hazard-free. By taking these comparatively simple steps, management can be sure that all equipment is in good operating condition and properly stored. Emergency equipment such as fire extinguishers and eyewash stations also should be inspected for proper operation.

Although most of the chemicals present in bottling plants are not extremely hazardous, every operation uses flammable substances, acids, caustics, corrosives and oxidants. Appropriate work practices should be developed so employees know how to work safely with these chemicals. They must be taught how properly to store, handle and dispose of the chemicals and how to wear protective gear. Training should cover the location and operation of emergency response equipment. Eyewash stations and showers can minimize injury to anyone who is accidentally exposed to a hazardous chemical.

It also is necessary to install equipment such as chemical booms and dykes, as well as absorbent material, to be used in the event of a spill. Properly designed hazardous chemical storage facilities will minimize the risk of employee injury, too. Flammables should be separated from corrosives and oxidants.

The large tanks used for mixing ingredients, which need to be entered and cleaned routinely, are considered confined spaces. See the box on confined spaces in this chapter for information on the related hazards and precautions.

Mechanized equipment has become increasingly complex, often controlled by remote computers, pneumatic lines or even gravity. Employees must be sure that this equipment has been de-energized before it is serviced. Proper de-energizing procedures must be developed to guarantee the safety of those who maintain and repair this equipment. Energy must be shut off and locked out at its source so that the unit being serviced cannot be accidentally energized, causing potentially fatal injuries to service employees or nearby line operators.

Safety training and written de-energizing procedures are critical for each piece of equipment. Emergency stop switches should be strategically placed on all equipment. Interlocked safety devices are used to stop the equipment automatically when doors are opened or light beams are interrupted. Employees must be informed, however, that these devices cannot be relied upon to completely de-energize the equipment, but only to stop it in an emergency. Emergency stop switches cannot take the place of a proven de-energizing procedure for equipment maintenance.

Chlorine, which is used in the water treatment area, could be hazardous in the event of an accidental release. Chlorine typically comes in steel cylinders, which should be stored in an isolated, well-ventilated area and secured from tipping. Employees should be trained to follow safe cylinder-changing procedures. They also should be taught how to take quick, decisive action if an accidental release of chlorine occurs. In the late 1990s new chlorine compounds are gradually replacing the need for chlorine gas. Although still hazardous, these compounds are much safer to handle than gas.

Ammonia is used as a refrigerant in bottling operations. Typically, large ammonia systems can create a health hazard in the event of a leak or a spill. Bottling facilities should develop emergency response procedures to identify the responsibilities of involved employees. Those who are required to respond to such an emergency must be trained in spill response and respirator use. In the event of a leak or spill, respirators should be immediately available, and all non-essential personnel evacuated to safe areas until the situation is controlled.

CO₂, which is used in the filling operation, also can create health concerns. If filling rooms and adjacent work areas are not adequately ventilated, CO₂ accumulation can displace oxygen in employees’ breathing zones. Facilities should be monitored regularly for elevated CO₂ levels and, if they are detected, ventilation systems should be inspected to determine the cause for this occurence. Additional ventilation may be required to correct the situation.

Technological advances have made available better sound-absorption material for insulating or muffling motors and gears in most equipment. Still, given the function and size of filling equipment, noise levels generally exceed 90 dBA in this area. Employees who are exposed to this level of noise for an 8-hour weighted average must be protected. Good hearing protection programmes should include research on better ways to control noise; employee education on related health effects; personal noise protection; and training on how to use hearing protection devices, the wearing of which must be enforced in high-noise areas. Employee hearing must be routinely checked.

Fork-lifts are operated throughout the bottling plant and their safe use is imperative. In addition to demonstrating their driving skills, potential operators must understand fork-lift safety principles. Licenses are commonly issued to show that a minimum level of competency has been achieved. Fork-lift safety programmes should include a pre-use inspection process, whereby the vehicles are checked to ensure that all safety equipment is in place and working. Any deficient conditions should be immediately reported and corrected. Gas or liquid petroleum (LP) fork-lifts generate carbon monoxide as a by-product of combustion. Such emissions can be minimized by keeping the fork-lift engines tuned to manufacturers’ specifications.

Personal protective equipment (PPE) is common throughout the bottling facility. Filling-room employees wear eye and ear protection. Sanitation crews wear face, hand and foot protection that is appropriate for the chemicals they are exposed to. While slip-resistant shoes are recommended throughout the plant, maintenance employees should also have the added protection of steel-toed shoes. The key to a good PPE programme is to identify and evaluate the potential hazards associated with each job and to determine whether those hazards can be eliminated through engineering changes. If not, PPE must be selected to address the specific hazard at hand.

Management’s role is critical in identifying hazards and developing practices and procedures to minimize them in the workplace. Once developed, these practices and procedures must be communicated to employees so that they can perform their jobs safely.

As plant technology continues to advance—providing better equipment, new guards and protective devices—soft drink bottlers will have even more ways to maintain the safety of their workforce.

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General Overview

Coffee as a beverage was introduced in Europe during the sixteenth century, first in Germany and then throughout the European continent during the following century, especially to France and Holland. Afterwards, it spread to the rest of the world.

Since coffee will not keep its characteristic smell and flavour for long, after roasting and grinding, industrial establishments to roast and grind coffee have become needed wherever coffee is consumed. The establishments are usually small or medium-sized plants, but large factories do exist, mainly to produce regular as well as instant (soluble) coffee.

It is difficult to estimate the number of workers employed by the coffee industry. Some of the smaller plants do not keep registries, and figures are not entirely reliable. Considering a total consumption of approximately 100 million 60 kg bags of coffee during the year 1995, the worldwide coffee trade represents about US$50 million. Table 1 lists selected coffee-importing countries, giving an idea of the present world consumption.

Table 1. Selected coffee importers (in tonnes).

Source: FAO 1992.

Coffee manufacturing is a relatively simple process, including cleaning, roasting, grinding and packing processes, as shown in figure 1. However, modern technology has led to complex processes, with an increase in speed of production and requiring laboratories for quality-control testing of the product.

Figure 1. Flow chart of coffee manufacturing.

Coffee beans arrive at factories in 60 kg bags, which are unloaded mechanically or manually. In the latter case, usually two workers hold a bag and place it upon another worker’s head. This worker will carry the bag to be stored. Even when transportation is done on coveyor belts, some physical effort with high energy consumption is required.

The use of instant coffee has steadily increased, reaching approximately 20% of the world consumption. Instant coffee is obtained through a complex process in which blasts of hot air blow over coffee extracts, followed by evaporation, cooling and lyophilization (freeze drying), varying in details from one factory to another. In the manufacture of decaffeinated coffee, which represents over 10% of the consumption in the United States and in Europe, some plants still utilize chlorinated solvents (such as methylene chloride), which is removed by a blast of water vapour.

Potential Risks and Health Effects

To start coffee processing, bags are opened with a small knife, and the beans are thrown inside a bin to be cleaned. The work area is noisy and a large amount of residual particulate material remains in suspension, released from the cleaning machine.

Roasting exposes workers to risks of burns and thermal discomfort. Bean mixing, or blending, is done automatically, as is grinding, in areas which may be deficient in lighting due to interference from suspended coffee dust. Dirt may accumulate, noise levels may be high and mechanization requires work at a high speed.

After grinding, bags of different materials and sizes are filled and then packed, usually in cardboard boxes. When performed manually, these operations require high-speed repetitive motion of hands and arms. Cardboard boxes are transported to storage areas and then to their final destination.

The strong odour characteristic of the coffee industry may bother workers inside the plants, and the surrounding community as well. The significance of this problem as a potential health risk has not yet been clarified. The odour of coffee is due to a mixture of different products; research is ongoing to identify individual effects of these chemicals. Some components of the coffee dust and some of the odour-producing substances are known to be allergens.

Potential risks in instant-coffee plants are similar to those in regular coffee production; in addition, there are risks due to hot steam and boiler explosions. In the removal of caffeine, even when performed automatically, the risk of solvent exposure may be present.

Other potential risks which may affect workers’ health are similar to those found in food industries in general. Risks for accidents arise from cuts from knives used in bag opening, burns during roasting and crushing during grinding operations, especially in old machinery without automatic machine guarding. There are fire and explosion hazards from the large amounts of dust, unsafe electric wiring and gas used for heating the roasters.

Several hazards may be found in the coffee industry including, among others: hearing loss due to excessive noise, thermal stress during roasting, poisoning from pesticides and musculoskeletal disorders, especially affecting the backs of workers who lift and carry heavy bags.

Allergic disorders affecting the eye, skin or respiratory system may occur in any area in a coffee plant. It is the coffee dust which is associated with bronchitis with lung function impairment; rhinitis and conjunctivitis are also concerns (Sekimpi et al. 1996). Allergic reactions to contaminants of bags previously used for other materials, such as castor bean seeds, have also occurred (Romano et al. 1995).

Repetitive-motion disorders may result from high-speed motion in packing operations, especially where workers are not warned of the risk.

In less developed countries, effects of occupational risks may develop early because conditions of work may be inadequate and, moreover, other social and public health factors may contribute to disease. Such factors include: low salaries, inadequate medical care and social security, improper housing and sanitation, low levels of education, illiteracy, endemic diseases and malnutrition.

Preventive Measures

Machine guarding, general ventilation and local exhaust systems, noise abatement, housekeeping and cleaning, decreased bag weights, substitutes of solvents used in caffeine extraction, periodic inspection and preventive maintenance of boilers are examples of preventive measures that are required for ensuring adequate levels of industrial hygiene and safety. Odour intensity may be reduced through modification of roasting procedures. The organization of work can be modified so that repetitive-motion disorders may be avoided through alteration of working position and rhythm, as well as the introduction of systematic breaks and regular exercises, among other practices.

Periodic health screening should stress evaluation of exposure to herbicides and pesticides, spinal disorders and early signs of repetitive-motion disorders. Scratch tests using extracts from coffee beans, even if not universally accepted as completely reliable, may be useful in the identification of hypersusceptible individuals. Lung function tests may aid in the early diagnosis of obstructive respiratory conditions.

Health education is an important instrument to enable workers to identify health risks and their consequences and to become aware of their right to a healthy working environment.

Governmental action is required, through legislation and enforcement; employers’ participation is needed in providing and maintaining adequate working conditions.

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Legend tells us that tea may have been discovered in China by Emperor Shen-Nung, “The Divine Healer”. Observant of the fact that people who drank boiled water enjoyed better health, the wise Emperor insisted on this precaution. When adding branches to the fire, some tea leaves accidentally fell into the boiling water. The Emperor approved of the pleasing aroma and delightful flavour and tea was born.

From China, tea spread throughout Asia, soon becoming the national beverage of China and Japan. It was not until the 1600s that Europe became familiar with the beverage. Shortly thereafter, tea was introduced to North America. In the early 1900s, Thomas Sullivan, a New York wholesaler, decided to package tea in small silk bags rather than in tins. People started brewing the tea in the silk bag rather than removing its contents. Thus the tea bag was first introduced.

Tea is the world’s second most popular drink; only water is consumed more often. Consumers can choose from a wide variety of tea products—instant tea, iced tea mixes, specialty and flavoured teas, herbal teas, ready-to-drink teas decaffeinated teas and tea bags. The packaging of tea products has changed significantly; most of the small shops that once dispensed tea from wooden crates into individual tins have given way to sophisticated high-speed production lines which process, package, and/or bottle thousands of pounds of tea and ready-to-drink mixes per hour.

Process Overview

Production of tea bags consists of the blending of various cut and dried leaf teas from a number of regions around the world. Tea is usually received in wooden crates or large bags. The tea is blended and sent to tea packaging machines, where it is packaged either as individual tea bags or in bulk packages. Instant powdered tea requires blended tea in cut leaf form to be brewed using hot water. The liquid tea concentrate is then spray dried into a fine powder and placed in drums. The tea powder may be sent to the packaging lines where it is packaged into canisters or jars, or blended with other ingredients such as sugar or sugar substitutes. Flavouring such as lemon and other fruit flavors may also be added during the blending stage prior to packaging.

Hazards

There are a number of common safety hazards and health issues associated with the blending, processing and packaging of tea. Safety hazards such as machine guarding, noise, slips and falls and lifting-related injuries are quite common within the beverage industry. Other hazards, such as dust in the blending and packaging areas, are not usually found in wet-process bottling and canning operations.

Machine hazards

The blending and packaging of tea involves equipment and machinery where workers are exposed to chains and sprockets, belts and pullies, rotating shafts and equipment and high-speed packaging lines containing a number of dangerous pinch points. Most injuries are the result of lacerations and bruises to the fingers, hands or arms. Guarding of this equipment is critical to protect workers from getting caught in, under or between moving parts. Guards and/or interlocks should be installed to protect workers from moving parts where the potential of injury exists. Whenever a guard is removed (such as for maintenance), all energy sources should be isolated and maintenance and repair of equipment should be with an effective lockout/tagout programme in effect.

Dust hazards

Tea dust can be present in blending and packaging operations. Tea dust may also be present in high concentrations during clean-up or blow-down operations. Tea dust with a diameter greater than 10 micrometers can be classified as “nuisance dust”. Nuisance dust has little adverse effect on the lungs and should not produce significant organic disease or toxic effects when exposures are kept under reasonable control. Excessive concentrations of nuisance dust in the workroom air, however, may cause unpleasant deposits in the eyes, ears and nasal passages. Once inhaled, these particles may become entrapped in the nasal and pharyngeal region of the respiratory system, until they are expelled through the body’s own cleaning mechanisms (e.g., coughing or sneezing).

Respirable dust particulates are those that are less than 10 micro-meters in diameter and therefore small enough to pass through the nasal and pharyngeal regions and enter the lower respiratory tract. Once in the lungs, they may become embedded in the alveolar region, where scar tissue could develop. Respirable particulates can be respiratory irritants, especially in asthmatics. Effective seals and closures will help contain dust particles.

Exhaust ventilation or other types of dust-control equipment should be provided at the site of dust production to maintain dust levels below generally recognized standards (10 mg/m3) or other government regulations that may apply. Dust masks should be worn by workers who may be highly sensitive to dusts and by workers exposed to large concentrations of dust at any one time. Persons with chronic bronchitis or asthma are at higher risk. Workers who suffer from hypersensitivity to tea dust should be removed from the area.

Although there is little information on actual tea dust explosions, test data indicate that the explosion characteristics of tea dust are relatively weak. It appears that the greatest potential for a tea dust explosion exists with storage bins and dust collectors where concentrations and particle size are optimized. Minimizing dust concentration within a room or process will reduce the potential of a dust explosion. Electrical equipment designed for dust hazard areas may also be desirable in some operations.

Although tea and tea dust may not always burst into flames, large quantities of tea will almost always smoulder if ignited. Large quantities of water in a fine mist can be used to cool the smouldering tea below its ignition temperature.

Noise

As in most high-speed packaging operations, high noise levels are almost always present in the tea industry. High noise levels can be generated from vibrating blenders, air-operated and other packaging machines, air conveying systems, dust collectors and box cutters. The noise levels in many of these areas can range from 85 dBA to over 90 dBA. The major potential health hazard associated with exposure to noise lies in the possibility of producing permanent hearing loss. The severity of hearing loss is dependent on the noise levels within the workplace, duration of the exposure and the individual’s personal susceptibility. Noise and hearing conservation programmes are discussed further elsewhere in this Encyclopaedia.

Chemical hazards

Although most of the production processes and packaging operations do not expose workers to hazardous chemicals, sanitation operations use chemicals to clean and sanitize equipment. Some cleaning chemicals are handled in bulk quantities through fixed pipe systems, while other chemicals are applied by hand using predetermined mixtures. Exposure to these chemicals can cause respiratory problems, dermatitis or skin irritation and chemical burns to the skin. Severe burns to the eyes and/or loss of vision are also hazards associated with the handling of cleaning chemicals. Proper evaluations as to the hazards of the chemicals being used are essential. Proper selection and use of PPE should be part of routine job procedure. PPE such as splash-proof goggles or face shields, chemical-resistant gloves, aprons, boots and a respirator should be considered. Emergency eye and body wash stations should be provided where hazardous chemicals are either stored, mixed or used.

Material handling

Tea arrives on pallets in either bags or crates and is stored in warehouses to await blending and packaging. These bags and crates are moved either by hand or by material-handling devices such as fork-lifts or vacuum lifts. Once blended, the tea is conveyed to hoppers for packaging. Packaging operations can vary from using highly automated equipment to labour-intensive hand packaging operations (figure 1). Injuries to the lower back resulting from lifting tasks are quite common when handling bags weighing 100 pounds (45.5 kg) or more. Repetitive motions on packaging lines can result in cumulative trauma to the wrist, arm and/or shoulder area.

Figure 1. Packing of tea at the Brooke Bond tea and coffee factory in Dar-es-Salaam, Tanzania.

Mechanical devices such as vacuum lifts can aid in reducing heavy lifting tasks. Assigning two workers to a heavy lifting task can help reduce the chances of a serious back injury. Modifying work stations to be more ergonomically correct and/or automating equipment on packaging lines can reduce worker exposure to repetitive tasks. Rotating workers to light duty tasks can also reduce worker exposure to such tasks.

Personal aids such as back belts and wrist bands are also used by some workers to assist them in their lifting tasks or for temporary relief of minor strains. However, these have not been shown to be effective, and they may even be harmful.

Most warehouse operations require the use of fork-lift trucks. Failure to drive at safe speeds, sharp turns, driving with raised forks, failure to observe or yield to pedestrians and loading/ unloading accidents are the leading causes of injuries involving fork-lift operators. Only trained and competent operators should be permitted to drive fork-lifts. Training should consist of formal classroom training and a driving test where operators can demonstrate their skills. Proper maintenance and daily pre-use inspections also help ensure the safe operation of these vehicles.

Slips, trips and falls

Slips, trips and falls are a major concern. In dry blending and packaging operations, fine tea dust will accumulate on walking and working surfaces. Good housekeeping is important. Floors should be swept clean of tea dust on a regular basis. Debris and other items left on the floor should be picked up immediately. Slip-resistant, rubber-soled shoes appear to provide the best traction. Wet-process areas also provide slip and fall hazards. Floors should be kept as dry as possible. Adequate floor drainage should be provided within all wet-process areas. Standing water should not be permitted to accumulate. Where standing water exists, it should be mopped into floor drains.

Exposure to high temperatures

Contact with hot water, steam lines and process equipment can result in serious injury from burns. Most burns occur on the hands, arms and face. Hot water used for clean-up or wash-down has also been known to cause burns on feet and legs.

Heat sealers and glue operations on packaging lines also can cause burns. Guarding of exposed hot points on equipment is important. The proper evaluation of the hazards, and selection and use of personal protective equipment, will also help reduce or eliminate worker exposure to high temperatures and burns. Use of pipeline breaking and lockout procedures will protect workers from the unexpected release of hot liquids and steam.

Safe Practices

A general safety programme which addresses the use and selection of PPE, entry into confined spaces, isolation of energy sources, identification and communication of hazardous chemicals, self-inspection programmes, hearing conservation programmes, the control of infectious materials, process management and emergency response programmes should also be included as part of the work process. Training of workers in safe work practices is important in reducing worker exposure to hazardous conditions and injuries.

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