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Health Effects and Disease Patterns

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Health effects found in food processing are similar to those found in other manufacturing operations. Respiratory disorders, skin diseases and contact allergies, hearing impairment and musculoskeletal disorders are among the most common occupational health problems in the food and beverage industry (Tomoda 1993; BLS 1991; Caisse nationale d’assurance maladie des travailleurs salariés 1990). Thermal extremes are also a concern. Table 1 shows rankings of the three most common occupational diseases in this industry in selected countries.

Table 1. Most common occupational diseases in the food and drink industries in selected countries



Occupational diseases


Most common

Second most common

Third most common




Bronchitis, asthma

Hearing impairment

Skin diseases

Infections transmitted by animals

Belgium (food)


Diseases induced by inhalation of substances

Diseases induced by physical agents

Skin diseases

Infections or parasites from animals

Belgium (drink)


Diseases induced by physical agents

Diseases induced by chemical agents

Diseases induced by inhalation of substances



Hearing impairment

Respiratory disorders (asthma)

Musculoskeletal disorders

Skin diseases



Respiratory disorders

Musculoskeletal disorders

Digestive disorders

Circulatory disorders, skin diseases



Physical coordination disorders

Skin diseases

Hearing impairment

Infections, allergies



Asthma and other respiratory disorders

Strains in various parts of body (knees, elbows)

Septicemia (blood poisoning) and other infections

Hearing impairment



Respiratory disorders

Skin diseases


Hearing impairment



Musculoskeletal disorders

Allergies (contact with chemical agents)

Hearing impairment


United States


Disorders associated with repeated trauma

Skin diseases

Diseases due to physical agents

Respiratory conditions associated with toxic agents

Source: Tomoda 1993.

Respiratory System

Respiratory problems can largely be classified as rhinitis, which affects the nasal passages; broncho-constriction in the major airways; and pneumonitis, which consists of damage to the fine structures of the lung. Exposure to airborne dust from various foodstuffs, as well as chemicals, may lead to emphysema and asthma. A Finnish study found chronic rhinitis common among slaughterhouse and pre-cooked foods workers (30%), mill and bakery workers (26%) and food processing workers (23%). Also, food processing workers (14%) and slaughterhouse/pre-cooked foods workers (11%) suffered from chronic coughs. The causative agent is flour dust in bakery workers, while temperature variations and various kinds of dust (spices) are believed to cause disease in other branches.

Two studies in the former Yugoslavia found a much higher prevalence of chronic respiratory symptoms than in a control group. In a study of spice workers the most common complaint (57.6%) was dyspnea or breathing difficulty, followed by nasal catarrh (37.0%), sinusitis (27.2%), chronic cough (22.8%) and chronic phlegm and bronchitis (19.6%). A study of animal food processing workers found that in addition to the animal food processing ingredients, exposure included powdered coriander, garlic dust, cinnamon dust, red paprika dust and dust from other spices. Non-smokers studied showed a significantly higher prevalence of chronic phlegm and chest tightness. Smokers had a significantly higher prevalence of chronic coughs; chronic phlegm, chronic bronchitis and chest tightness were also observed. The frequency of acute respiratory symptoms associated with the working day was high for the exposed group, and respiratory ventilatory capacity of smokers was significantly lower than predicted. The study therefore concluded an association exists between exposure to animal food dust and the development of respiratory disorders.

Industrial injury compensation in the United Kingdom recognizes occupational asthma from the handling of enzymes, animals, grains and flour. Exposure to cinnamic aldehyde from tree bark and sulphur dioxide, a bleaching agent and fumigant, cause a high prevalence of asthma in cinnamon workers in Sri Lanka. Dust exposure is minimal for the workers who peel the bark, but workers in the local buyers’ stores are exposed to high levels of dust and sulphur dioxide. A study found 35 of 40 cinnamon workers complained of chronic coughs (37.5%) or suffered from asthma (22.5%). Other abnormalities included weight loss (65%), skin irritation (50%), hair loss (37.5%), eye irritation (22.5%) and rashes (12.5%). For workers who work under similar high concentrations of airborne dust of vegetable origin, asthma is highest in cinnamon workers (22.5%, compared with 6.4% in tea workers and 2.5% in kapok workers). Smoking is not believed to be directly related to the coughs, since similar symptoms occurred in 8 non-smoking women and 5 men who smoked about 7 cigarettes a day. Irritation of the respiratory mucosa by cinnamon dust causes the coughing.

Other studies examined the relationship between respiratory disorders and the allergens and antigens originating in foodstuffs, such as egg protein and seafood products. While no specific workplace dust could be linked to the various acute and chronic respiratory disorders among the exposed workers, the results of the studies indicate a strong association between the disorders and the work environment.

Use of microbiology has long been a part of food production. In general, most of the micro-organisms used in the food and drink industries are considered to be harmless. Wine, cheese, yogurt and sour dough all use a microbial process to yield a usable product. Production of proteins and enzymes increasingly use biotechnological techniques. Certain species of aspergillus and bacillus produce amylases that convert starches into sugar. Yeasts turn starch into acetone. Tricoderma and Penicillium produce cellulases that break down cellulose. As a result, spores of fungi and actinomycetes are widely found in food processing. Aspergillus and Penicillium are frequently present in the air in bakeries. Penicillium is also found in dairy and meat processing plants; during the maturation of cheeses and sausages, there can be abundant surface growth. Cleaning steps, prior to sale, disperse them into the air, and workers may develop allergic alveolitis. Occupational asthma cases have association with many of these organisms, while some are suspected of causing infection or carrying mycotoxins. The enzymes trypsin, chymotrypsin and protease are associated with hypersensitivity and respiratory disease, particularly among laboratory workers.

In addition to the airborne particulate originating from foodstuffs and microbial agents, inhalation of hazardous chemical substances used as reagents, refrigerants, fumigants and sanitizers may cause respiratory and other disorders. These substances are found in solid, liquid or gaseous form. Exposure at or above recognized limits often results in skin or eye irritation and respiratory disorders. Headaches, salivation, burning of the throat, perspiration, nausea and vomiting are symptoms of intoxication due to overexposure.

Ammonia is a colourless gas refrigerant, cleaning agent and fumigant for foodstuffs. Exposure to ammonia can result in corrosive burns or blistering of skin. Excessive and prolonged exposure can produce bronchitis and pneumonia.

Trichloroethylene, hexane, benzene, carbon monoxide (CO), carbon dioxide (CO2) and polyvinyl chloride (PVC) are frequently found in food and beverage plants. Trichloroethylene and hexane are used for olive oil extraction.

CO, a colourless, odourless gas, is difficult to detect. Exposure occurs in smokehouses that are poorly ventilated or while working in grain silos, wine fermentation cellars or where fish are stored. Dry-ice freezing or chilling, CO2-freeze tunnels and combustion processes expose workers to CO2. Intoxication symptoms of overexposure to CO and CO2 include headache, dizziness, drowsiness, nausea, vomiting and, in extreme cases, even death. CO also can aggravate heart and respiratory symptoms. The acceptable exposure limits, set by several governments, permit 100 times greater exposure to CO2 than CO to trigger the same response.

PVC is used for packaging and food-wrap materials. When PVC film is heated, thermal degradation products cause irritation to the eyes, nose and throat. Workers also report symptoms of wheezing, chest pains, breathing difficulties, nausea, muscle pains, chills and fever.

Hypochlorites, acids (phosphoric, nitric and sulphuric), caustics and quaternary ammonium compounds are frequently used in wet cleaning. Microbiology labs use mercury compounds and formaldehyde (gas and formalin solution). Disinfection in the lab uses phenolics, hypochlorites and glutaraldehyde. Irritation and corrosion to eyes, skin and lungs occur with excessive exposure and contact. Improper handling can release highly toxic substances, like chlorine and sulphur oxides.

The National Institute for Occupational Safety and Health (NIOSH) in the United States reported worker breathing difficulties during washing of poultry with super-chlorinated water. The symptoms included headaches, sore throat, tightness in the chest and difficulty breathing. Chloramine is the suspected agent. Chloromines can form when ammonia-treated water or amine-treated boiler water contacts hypochlorite solutions used in sanitation. Cities have added ammonia to water to prevent the formation of halomethanes. Air sample methods are not available for chloramines. Chlorine and ammonia levels are not predictive as indicators of exposure, as testing found their levels to be well below their limits.

Fumigants prevent infestation during storage and transport of food raw materials. Some fumigants include anhydrous ammonia, phostoxin (phosphine) and methyl bromide. The short duration of this process makes respiratory protection the cost-effective strategy. Proper respiratory protection practices should be observed when handling these items until air measurements of the area are below applicable limits.

Employers should take steps to assess the level of toxic contamination at the workplace and ensure that exposure levels do not exceed limits found in safety and health codes. Contamination levels should be measured frequently, especially following changes in processing methods or the chemicals used.

Engineering controls to minimize the risk of intoxication or infection have two approaches. First, eliminate the use of such materials or substitute a less hazardous material. This may involve replacing a powdered substance with a liquid or slurry. Second, control the exposure through reducing the level of air contamination. Workplace designs include the following: total or partial enclosure of the process, suitable ventilation systems and restricted access (to reduce exposed population). An appropriate ventilation system is instrumental in preventing the dispersal of spores or aerosols throughout the workplace. Substitution of vacuum cleaning or wet cleaning for compressed-air blow-out of equipment is critical for dry materials that could become airborne during cleaning.

Administrative controls include worker rotation (to reduce exposure period) and off-shift/weekend hazardous task work (to reduce exposed population). Personal protective equipment (PPE) is the least favoured exposure control method due to high maintenance, availability issues in developing countries and the fact that the worker must remember to wear it.

PPE consists of splash goggles, face shields and respirators for workers mixing hazardous chemicals. Worker training on use and limitations, plus equipment fitting, must occur for the equipment to adequately serve its purpose. Different types of respirators (masks) are worn depending on the nature of the work and the level of the hazard. These respirators range from the simple half facepiece for dust and mist, through chemical air purifying of various facepiece types, up to self-contained breathing apparatus (SCBA). Proper selection (based on hazard, face-fit and maintenance) and training assure effectiveness of the respirator in reducing exposure and the incidence of respiratory disorders.


Skin problems found in the food and drink industries are skin disease (dermatitis) and contact allergies (e.g., eczema). Due to sanitation requirements, workers are constantly washing their hands with soap and using hand-dip stations that contain quaternary ammonium solutions. This constant wetting of the hands can reduce the lipid content of the skin and lead to dermatitis. Dermatitis is an inflammation of the skin as a result of contact-exposure to chemicals and food additives. Work with fats and oils can clog the pores of the skin and lead to acne-like symptoms. These primary irritants account for 80% of all occupational dermatitis seen.

There is growing concern that workers may become highly sensitized to microbial proteins and peptides generated by fermentation and extraction, which can lead to eczema and other allergies. An allergy is a hypersensitive response of any type that is greater than that which normally occurs in response to antigens (not-self) in the environment. Allergic contact dermatitis is rarely seen before the fifth or seventh day after exposure is initiated. Hypersensitivity occupational dermatitis is also reported for work with enzymes, such as trypsin, chymotrypsin and protease.

Chlorinated solvents (see “Respiratory system” section above) stimulate the epidermal cells to undertake peculiar growth patterns. This keratin stimulation may lead to tumour formation. Other chlorinated compounds found in soaps for antibacterial purposes can lead to photosensitivity dermatitis.

Reduction of exposure to causative agents is the principle preventive method for dermatitis and contact allergies. Adequately drying foodstuffs prior to storage and clean-condition storage can control airborne spores. PPE such as gloves, masks and uniforms keep workers from direct contact and minimize the risk of dermatitis and other allergies. Latex glove materials can cause allergic skin reactions and should be avoided. Proper application of barrier creams, where permitted, can also minimize contact with the skin irritant.

Infectious and parasitic diseases of animal origin are the occupational diseases most specific to the food and drink industries. The diseases are most common among meat-packing and dairy workers as a result of direct contact with infected animals. Agricultural workers and others are also at risk due to their contact with these animals. Prevention is particularly difficult since the animals may not give any overt signs of disease. Table 2 lists the types of infections reported.

Table 2. Types of infections reported in food and drink industries




Brucellosis (Brucella melitensis)

Contact with infected cattle, goats and sheep (Northern and Central Europe and North America)

Constant and recurring fever, headaches, weakness, joint pain, night sweats and loss of appetite; can also give rise to symptoms of arthritis, influenza, asthenia and spondylitis


Contact of open wounds with infected pigs and fish (Czechoslovakia)

Localized redness, irritation, a burning sensation, pain in the infected area. It can spread to the bloodstream and lymph nodes.


Direct contact with infected animals or their urine

Headaches, aching muscles, eye infections, fever, vomiting and chills; in more serious cases, kidney and liver damage, plus cardiovascular and neurological complications


Caused by a parasitic fungus on the skin of animals

Erythema and blistering of skin

Dematophytosis (ringworm)

Fungal disease through contact with skin and hair of infected animals

Localized hair loss and small crusts on the scalp


Contact with infected sheep, goats, cattle, pigs and poultry

Acute stage: fever, muscle pain, sore throats, headaches, swollen lymph nodes and enlarged spleen. Chronic infection leads to development of cysts in the brain and muscle cells. Foetal transmission causes still- and premature births. Full-term babies can have brain and heart defects and may die.

Papilloma viral lung cancers

Regular contact with live animals or animal flesh coupled with exposure to polycyclic aromatic hydrocarbons and nitrites

Lung cancers in butchers and slaughterhouse workers studied in England, Wales, Denmark and Sweden


The fundamental principle for preventing the contraction and spread of infectious and parasitic skin diseases is personal hygiene. Clean washrooms, toilets and shower facilities should be provided. Uniforms, PPE and hand towels need to be washed and in some cases sterilized frequently. All wounds should be sterilized and dressed, regardless of how slight, and covered with protective gear until healed. Keeping the workplace clean and healthy is just as important. This includes the thorough washing of all equipment and surfaces that contact animal flesh after each workday, the control and extermination of rodents and the exclusion of dogs, cats and other animals from the workplace.

Vaccination of animals and inoculation of workers are measures many countries take to prevent infectious and parasitic diseases. Early detection and treatment of diseases with antibacterial/anti-parasitic drugs is essential to contain and even eradicate them. Workers should be examined as soon as any symptoms, such as recurring coughs, fever, headaches, sore throats and intestinal disorders, appear. In any case, workers should undergo medical examinations at established frequencies, including pre-placement/post-offer baseline exams. In some countries, authorities must be notified when examination detects work-related infection in the workers.

Noise and Hearing

Hearing impairment occurs as a result of continuous and prolonged exposure to noise above recognized threshold levels. This impairment is an incurable illness causing communication disorders and is stressful if the work demands concentration. As a result, psychological and physiological performance can deteriorate. There is also an association between high noise level exposure and abnormal blood pressure, heartbeat, respiration rate/volume, stomach and intestinal spasms and nervous disorders. Individual susceptibility, exposure duration and noise frequency plus intensity are factors that determine the exposure risk.

Safety and health codes vary from country to country, but worker exposure to noise is usually limited to 85 to 90 dBA for 8 continuous hours, followed by a 16-hour recovery time below 80 dBA. Ear protection should be made available at 85 dBA and is required for workers with a confirmed loss and for 8-hour exposures at or above 90 dBA. Annual audiometric testing is recommended, and in some countries required, for this exposed population. Noise measurements with a meter such as the American National Standards Institute (ANSI) Type II sound meter should be taken at least every 2 years. Readings should be repeated whenever equipment or process changes could increase the ambient noise levels.

Ensuring that noise exposure levels are not hazardous is the primary strategy for noise controls. Good manufacturing practices (GMPs) dictate that control devices and their exposed surfaces be cleanable, do not harbour pests and have necessary approvals to contact food or be ancillary to food production. The methods adopted also depend on the availability of financial resources, equipment, materials and trained staff. One of the most important factors in noise reduction is the design of the workplace. Equipment should be designed for low noise and low vibration. Replacing metal parts with softer materials, like rubber, can reduce noise.

When new or replacement equipment is purchased a low-noise type should be selected. Silencers should be installed at air valves and exhaust pipes. Noise-producing machines and processes should be enclosed to reduce to a minimum the number of workers exposed to high noise levels. Where permitted, noise-proof partitions and noise-absorbing ceilings should be installed. Removal and cleaning of these partitions and ceiling tiles need to be included in the maintenance costs. The optimum solution is usually a combination of these measures, adapted to the needs of each workplace.

When engineering controls are not feasible or when it is impossible to reduce noise below harmful levels, PPE should be used to protect the ears. Protective equipment availability and worker awareness is important to prevent hearing impairment. In general, a selection of plugs and earmuffs will lead to greater acceptance and wearing.

Musculoskeletal System

Musculoskeletal disorders were also reported in the 1988–89 data (see table 1]). Data in the early 1990s noted more and more workers reporting occupational musculoskeletal disorders. Plant automation and work whose pacing is regulated by a machine or conveyor belt occurs today for more workers in the food industry than ever before. Tasks in automated plants tend to be monotonous, with workers performing the same movement all day long.

A Finnish study found that nearly 40% of survey participants reported performing repetitive work all day. Of those performing repetitive work, 60% used their hands, 37% used more than one part of the body and 3% used their feet. Workers in the following occupational groups perform repetitive work for two-thirds or more of their working hours: 70% of cleaners; 67% of slaughterhouse, pre-cooked food and packaging workers; 56% of warehouse and transport workers; and 54% of dairy workers.

Ergonomic stresses arise because most food products come from natural sources and are not uniform. Meat handling requires workers to handle carcasses of varying sizes. With the introduction of poultry sold in parts in the 1960s, more birds (40%, up from less than 20%) were cut into parts. Workers must make many cuts using sharp tools. Changes in US Department of Agriculture (USDA) inspection procedures now permit average line speeds to increase from 56 to 90 birds per minute. Packaging operations may involve repetitive hand and wrist motions to place finished items undamaged into trays or packs. This is especially true for new products, as the market may not justify high-volume operations. Special promotions, including recipes and coupons, may require that an item be manually inserted into the package. Ingredient packaging and workplace layout may require lifting beyond the action limits recommended by occupational health agencies.

Repetitive strain injuries (RSIs) include inflammation of the tendon (tendinitis) and inflammation of the tendon sheath (tenosynovitis). These are prevalent among workers whose jobs require repetitive hand movements, like meatpacking workers. Tasks that repeatedly combine the bending of the wrist with gripping, squeezing and twisting motion can cause carpal tunnel syndrome (CTS). CTS, characterized by a tingling sensation in the thumb and first three index fingers, is caused by inflammation in the wrist joint creating pressure on the nerve system in the wrist. Misdiagnosis of CTS as arthritis can result in permanent numbness and severe pain in the hands, elbows and shoulders.

Vibration disorders also accompany an increased level of mechanization. Food workers are no exception, although the problem may not be as serious as for certain other industries. Food workers using machines such as band saws, mixers and cutters are exposed to vibration. Cold temperatures also increase the probability of vibration disorders to the fingers of the hand. Five per cent of the participants in the Finnish study noted above were exposed to a fairly high level of vibration, while 9% were exposed to some level of vibration.

Excessive exposure to vibration leads, among other problems, to musculoskeletal disorders in the wrists, elbows and shoulders. The type and degree of disorder depend on the type of machine, how it is used and the level of oscillation involved. High levels of exposure can result in growth of a protuberance on the bone or the gradual destruction of the bone in the joint, resulting in severe pain and/or limited mobility.

Rotation of workers with a view to avoiding repetitive motions may reduce the risk by sharing the critical task across the team. Teamwork by task rotation or two-person handling of awkward/heavy ingredient bags can reduce the stress on a single worker in material handling. Tool maintenance, especially knife sharpening, also plays an important role. An ergonomic team of management and production workers can best address these issues as they arise.

Engineering controls focus on reduction or elimination of the 3 primary causes of musculoskeletal problems—force, position and repetition. The workplace should be analysed to identify needed changes, including workstation design (favouring adjustability), working methods, task automation/mechanical assists and ergonomically sound hand tools.

Adequate training should be provided to workers using knives on keeping the knife sharp to minimize force. Also, plants must provide adequate knife-sharpening facilities and avoid the cutting of frozen meat. Training encourages workers to understand the cause and prevention of musculoskeletal disorders. It reinforces the need to use correctly the tools and machines specified for the task. It should also encourage workers to report medical symptoms as soon as possible. Elimination of more invasive medical intervention by restriction of duties and other conservative care, is effective treatment of these disorders.

Heat and Cold

Thermal extremes exist in the food work area. People must work in freezers with temperatures of –18 °C or below. Freezer clothing helps insulate the worker from the cold, but warm break rooms with access to warm liquids must be provided. Meat-processing plants must be kept at 7 to 10 °C. This is below the comfort zone and workers may need to wear additional clothing layers.

Ovens and steam cookers have radiant and moist heat. Heat stress can occur during season changes and heat waves. Copious amounts of fluids and salting of foods may relieve the symptoms until the worker can acclimatize, usually after 5 to 10 days. Salt tablets are not recommended due to complications of hypertension or gastrointestinal upset.



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Food Industry References

Bureau of Labor Statistics (BLS). 1991. Occupational Injuries and Illnesses in the United States by Industry, 1989. Washington, DC: BLS.

Caisse nationale d’assurance maladie des travailleurs salariés. 1990. Statistiques nationales d’accidents du travail. Paris: Caisse Nationale d’assurance maladie des Travailleurs Salariés.

Hetrick, RL. 1994. Why did employment expand in poultry processing plants? Monthly Labor Review 117(6):31.

Linder, M. 1996. I gave my employer a chicken that had no bone: Joint firm-state responsibility for line-speed-related occupational injuries. Case Western Reserve Law Review 46:90.

Merlo, CA and WW Rose. 1992. Alternative methods for disposal/utilization of organic by-products—From the literature”. In Proceedings of the 1992 Food Industry Environmental Conference. Atlanta, GA: Georgia Tech Research Institute.

National Institute for Occupational Safety and Health (NIOSH). 1990. Health Hazard Evaluation Report: Perdue Farms, Inc. HETA 89-307-2009. Cincinnati, OH: NIOSH.

Sanderson, WT, A Weber, and A Echt. 1995. Case reports: Epidemic eye and upper respiratory irritation in poultry processing plants. Appl Occup Environ Hyg 10(1): 43-49.

Tomoda, S. 1993. Occupational Safety and Health in the Food and Drink Industries. Sectoral Activities Programme Working Paper. Geneva: ILO.