Gill et al. outline the allergic dis- eases commonly encountered ... Current Allergy & Clinical Immunology, November/December 2002 Vol 15, No. 4. EDITORIAL.
EDITORIAL OCCUPATIONAL In this issue dedicated to occupational allergies, we focus on allergies in the food industry. Workers considered to be at increased risk include farmers who grow and harvest crops, and factory workers involved in food processing, manufacturing and storage, as well as those involved in food preparation (chefs and waiters). By far the largest food-handling population in South Africa is employed in agriculture (1.5 million, 50% in the informal sector), followed by the food manufacturing and processing industry that employs another 180 000 workers involved in a broad spectrum of occupations (Statistics South Africa, Feb/March 2002). These include sectors involved in processing of meat, fish, fruit, vegetables, oils and fats; dairy products; grain mill products, starches and starch products (e.g. sweets, chocolates, confectionery), and prepared animal feeds; and beverages. Materials processed include both naturally occurring biological raw products (plant/vegetable, animal or microbial origin) and chemicals for food preservation, flavouring, packaging and labelling. These biological and chemical materials are known to contain sensitising agents capable of causing occupational allergies among high-risk working populations. Steinman presents a detailed review of the common food allergens (maize, soya, wheat, rye, coffee, seafood), mites and other pests such as cockroaches associated with food storage, as well as additives such as sulphites and fungal α-amylase used in food processing industries. Most of these biological agents, both naturally occurring and synthetically derived, contain high-molecular-weight (> 2 kDa) proteins which act as allergic sensitisers. Food processing activities such as thermal denaturation, acidification and fermentation may destroy allergens, cause conformational changes or result in the formation of new sensitising epitopes which may increase the allergenicity of the protein. In the occupational setting, allergic constituents of food products enter the body either through inhalation or dermal contact, resulting in adverse reactions on an irritant or allergic basis. Gill et al. outline the allergic diseases commonly encountered in the food industry, which include occupational asthma, rhinitis, conjunctivitis, dermatitis and hypersensitivity pneumonitis. Occupational asthma represents between 3% and 20% of all asthma cases and is the most common form of occupational lung disease. Occupational skin diseases may represent between 10% and 15% of all occupational diseases and have significant economic impact. A practical approach to diagnosis and treatment of affected individuals is presented, the mainstay of treatment being removal of the worker from exposure. In the South African setting, the Occupational Health and Safety Act (OHSA) makes it obligatory for medical practitioners to report all cases of suspected occupational disease to the Chief Inspector in the Department of Labour.1 Furthermore, since these diseases are frequently severe enough to cause considerable disability and even abandonment of trade, the practitioner is legally required to assist the affected worker in filing a 138
FOOD ALLERGIES worker’s compensation claim.2 The Compensation for Occupational Injuries and Diseases Act (COIDA) confers some important medical aid and social security benefits to affected workers once the claim has been accepted.1,3 The true burden of occupational allergic diseases in South Africa is unknown. Studies in Finland estimate that occupational allergies constitute 15% of all occupational diseases encountered.4 The proportion of adult cases of asthma attributable to occupational exposure is estimated to be 10 - 15%.5 Worldwide, the most commonly reported causes of asthma in the workplace are agents of biological origin such as cereal flours, enzymes, natural rubber latex, laboratory animals and some low-molecular-weight agents (isocyanates and acid anhydrides).6 Esterhuizen and Rees present data demonstrating that the food processing industry (grain milling, baking) in South Africa is one of the top three industries reporting workers with occupational allergies and asthma to the SORDSA voluntary surveillance programme. The most commonly encountered putative agents are flour (60%) and grain/maize (20%). On comparison of the data with other surveillance programmes internationally, the authors suggest possible underreporting to SORDSA from other high-risk sectors such as farming and animal processing. Recent studies among fish processing factories along the west coast of the Western Cape indicate that 16% of workers complained of work-related asthma symptoms and 3% had occupational asthma due to bony fish (pilchard and anchovy).7 Although cross-sectional studies among flour and grain mill workers in Cape Town indicate that between 17% and 37% of workers have occupational asthma, the disease has been poorly controlled.8 This is in part due to inadequate legislation regulating exposure standards for occupational allergens causing asthma. The current exposure standard for grain dust in South Africa is 10 times the internationally recommended exposure standard of 1 mg/m3 (ACGIH). Baatjies and Jeebhay provide some cogent arguments for a greater focus on prevention-related efforts, especially as they pertain to workers in the baking industry at risk of developing bakers’ asthma. These include greater emphasis on legislative reform and enforcement, with special consideration given to the promulgation of new legislation specifically dealing with respiratory sensitisers causing occupational asthma as the newly promulgated Regulations for Hazardous Biological Agents are likely to have limited impact.9 Furthermore, workplace interventions focussing on engineering controls and optimal industrial hygiene and medical surveillance are equally important. Quirce et al. demonstrate the usefulness of the specific bronchial provocation challenge for the identification of the specific agent, in this case, fungal α-amylase among workers with bakers’ asthma. Similarly, De Pater and Heederik outline the usefulness of environmental monitoring of the work environment in identifying high-risk work processes that could be targeted for dust reduction interventions in bakeries and flour mills. The study among table grape farm workers in the Hex River Valley of the Western Cape demonstrates that certain high-risk exposures experienced by workers in food cultivating farms can also result in allergy and asthma over and above common indoor allergens. It
Current Allergy & Clinical Immunology, November/December 2002 Vol 15, No. 4
has been suggested that Tetranychus urticae, the twospotted spider outdoor mite, a known cause of occupational asthma among fruit farmers, plays a role in the high prevalence (26%) of work-related wheezing reported by farm workers involved in pesticide application in table grape farm orchards. As new foods are developed, it is possible that new occupational reactions may occur during food processing. Of special interest is the recent introduction of genetically modified crops in South Africa that may contain novel proteins, not previously known, which may be capable of causing allergic reactions in the occupational setting well before these products are made available to the consumer market. It is therefore crucial that epidemiological surveillance programmes be initiated on sentinel groups such as workers in food processing plants to detect the emergence of new allergies and health risks at a very early stage.10 Manufacturer responsibility for product stewardship should include, among others, product labelling and accurate information on allergenicity of these products in material safety data sheets provided to workers and consumers handling these foods. In this way overall public health and safety will be ensured. Application of political and economic incentives such as specific legislation on occupational asthma, fines and taxes, consumer/labour union pressure and ethical export trade requirements can also play a major role in preventing occupational allergies among food workers in the future. Mohamed Jeebhay MB ChB, DOH, MPhil (Epi), MPH (Occ Med) Occupational and Environmental Health Research Unit, School of Public Health and Primary Health Care, University of Cape Town
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REFERENCES 1. Jeebhay MF. Health and safety legislation and worker’s compensation for allergic diseases of occupational aetiology. Current Allergy and Clinical Immunology 2000; 13(3): 4-8. 2. Jeebhay MF, Omar F, Kisting S, Edwards D, Adams S. Outcome of worker’s compensation claims submitted by the Workers’ Clinic in Cape Town. Occupational Health Southern Africa 2002; 8(1): 4-7. 3. Jeebhay MF, Ehrlich R. Occupational asthma in South Africa. In: Potter P, Lee S, eds. The Allergy Society of South Africa (ALLSA) Handbook of Practical Allergy, 2nd edition. Cape Town: ALLSA, 2001: 142-159 (http://www.allergysa.org) 4. Reijula K, Patterson R. Occupational allergies in Finland in 1981- 91. Allergy Proc 1994; 15(3): 163-168. 5. Blanc PD, Toren K. How much adult asthma can be attributed to occupational factors? Am J Med 1999; 107(6): 580-587. 6. Van Kampen V, Merget R, Baur X. Occupational airway sensitizers: an overview on the respective literature. Am J Ind Med 2000; 38(2): 164-218. 7. Jeebhay MF, Robins TG, Lopata A, et al. Occupational seafood allergy and asthma in South Africa. (Abstract 083). La Medicina del Lavaro 2002: 93(5): 426. 8. Jeebhay MF, Stark J, Fourie A, Robins T, Ehrlich R. Grain dust allergy and asthma among grain mill workers in Cape Town. Current Allergy and Clinical Immunology 2000; 13(3): 23-25. 9. Jeebhay MF. An approach to hazardous biological agents in the workplace - legal provisions and practical considerations. Occupational Health Southern Africa 2002; 8(2): 8-13. 10. Lack G, Chapman M, Kalsheker N, King V, Robinson C, Venables K. BSACI working party. Report on the potential allergenicity of genetically modified organisms and their products. Clin Exp Allergy 2002; 32(8): 1131-1143.
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Current Allergy & Clinical Immunology, November/December 2002 Vol 15, No. 4
