Effectiveness of interventions to reduce flour dust exposures in supermarket bakeries in South Africa

A cluster randomised controlled trial to reduce respiratory effects of cotton dust exposure among textile workers: the MultiTex RCT study

BACKGROUND

We determined the effectiveness of an intervention to reduce cotton dust-related respiratory symptoms and improve lung function of textile workers.

METHODS

We undertook a cluster randomised controlled trial at 38 textile mills in Karachi, Pakistan. The intervention comprised: training in occupational health for workers and managers, formation of workplace committees to promote a health and safety plan that included wet mopping and safe disposal of cotton dust, provision of simple face masks, and further publicity about the risks from cotton dust. Participating mills were randomised following baseline data collection. The impact of the intervention was measured through surveys at 3, 12 and 18 months using questionnaires, spirometry and dust measurements. The primary outcomes were 1) changes in prevalence of a composite respiratory symptom variable, 2) changes in post-bronchodilator percentage predicted forced expiratory volume in 1 s (FEV1) and 3) changes in cotton dust levels. These were assessed using two-level mixed effects linear and logistic regression.

RESULTS

Of 2031 participants recruited at baseline, 807 (40%) were available at the third follow-up. At that point, workers in the intervention arm were more likely to report an improvement in respiratory symptoms (OR 1.58, 95% CI 1.06-2.36) and lung function (FEV1 % pred: β 1.31%, 95% CI 0.04-2.57%). Personal dust levels decreased, more so in intervention mills, although we did not observe this in adjusted models due to the small number of samples.

CONCLUSION

We found the intervention to be effective in improving the respiratory health of textile workers and recommend scaling-up of such simple and feasible interventions in low- and middle-income countries.

Exposure Monitoring Strategies for Applying Low-Cost PM Sensors to Assess Flour Dust in Industrial Bakeries

Low-cost particulate matter (PM) sensors provide new methods for monitoring occupational exposure to hazardous substances, such as flour dust. These devices have many possible benefits, but much remains unknown about their performance for different exposure monitoring strategies in the workplace. We explored the performance of PM sensors for four different monitoring strategies (time-weighted average and high time resolution, each quantitative and semi-quantitative) for assessing occupational exposure using low-cost PM sensors in a field study in the industrial bakery sector. Measurements were collected using four types of sensor (PATS+, Isensit, Airbeam2, and Munisense) and two reference devices (respirable gravimetric samplers and an established time-resolved device) at two large-scale bakeries, spread over 11 participants and 6 measurement days. Average PM2.5 concentrations of the low-cost sensors were compared with gravimetric respirable concentrations for 8-h shift periods and 1-min PM2.5 concentrations of the low-cost sensors were compared with time-resolved PM2.5 data from the reference device (quantitative monitoring strategy). Low-cost sensors were also ranked in terms of exposure for 8-h shifts and for 15-min periods with a shift (semi-quantitative monitoring strategy). Environmental factors and methodological variables, which can affect sensor performance, were investigated. Semi-quantitative monitoring strategies only showed more accurate results compared with quantitative strategies when these were based on shift-average exposures. The main factors that influenced sensor performance were the type of placement (positioning the devices stationary versus personal) and the company or workstation where measurements were collected. Together, these findings provide an overview of common strengths and drawbacks of low-cost sensors and different ways these can be applied in the workplace. This can be used as a starting point for further investigations and the development of guidance documents and data analysis methods.

Occupational inhalant allergy in food handling occupations

PURPOSE OF REVIEW

Review article on recent developments on inhalant food allergens associated with occupational respiratory allergy and asthma.

RECENT FINDINGS

This review has found that occupational inhalant allergy in food handling occupations is a common and recognisable clinical entity (class 3 food allergy) in high-risk food occupations such as bakeries and seafood processing. Aerosolised food proteins from plant or animal food sources, additives and biological food contaminants cause occupational sensitization, rhinitis and asthma. The risk of allergy may be enhanced across the food value chain as a result of food processing techniques including the introduction of new food allergens in the food matrix. Occupational food allergy and asthma can be prevented by improved health-based exposure standards, workplace control measures, education and training activities, and early diagnosis accompanied with exposure reduction.

SUMMARY

Future studies need to focus on exposure-response studies to establish improved exposure limits especially for flour dust, the relevance of cooked vs raw foods in influencing risk, identifying and characterising major inhalant food allergens accompanied with component resolved diagnostic approaches, and evaluating the effectiveness of interventions for common high-risk food sensitizers causing occupational rhinitis and asthma.

Case Report: Occupational Dust Exposure Among Bakery Workers in Perth, Western Australia

Occupational dust exposure can occur in various settings, including bakeries. A case study was conducted in an industrial bakery in Perth, Western Australia, to assess exposure to particulate dust concentration. The factory was separated into three production zones and an office area which represented as a control zone. Results indicated that bakery workers in the production zones were exposed to higher ambient dust particle concentrations compared to those from the office environment. Coarse particles (>10 μm in aerodynamic diameter) were the predominant particle size fraction measured in all studied areas with the highest median exposure level recorded in the dough room (0.181 mg/m3, interquartile range 0.283). High personal concentration of respirable particles was also measured in the dough room (median 2.26 mg/m3) which exceeded the recommended limit of 1.5 mg/m3 and was more than 50 times higher than the concentration recorded in the office (0.04 mg/m3). The variation in dust concentrations between production zones underlines the need of more knowledge about how aerosol fractions are distributed across the production process. The findings also suggest that bakery workers are exposed to high dust levels that may increase their risk of developing respiratory diseases and the decrease of present exposure levels is imperative.

Controlling flour dust exposure by an intervention focused on working methods in Finnish bakeries: a case study in two bakeries

Objectives. The purpose of this study was to examine the effectiveness of intervention strategies to control mass concentrations and peak exposures of flour dust in two Finnish bakeries. The effect of the intervention on the proportion of various particle size fractions of the total particulate matter was also investigated. Methods. Mass concentrations of flour dust were measured during three working days in a pre-intervention and post-intervention study in both an industrial and a traditional bakery. Gravimetric sampling and real-time measurements were performed. Relevant intervention strategies focused on working methods were planned in collaboration with the managers of the bakeries. Results. The average mass concentration of inhalable flour dust reduced in most of the stationary locations post intervention. The reductions in exposure levels were between 39 and 45%. However, the exposure levels increased 28-55% in the breathing zone. Real-time measurements showed reductions in the peak mass concentrations in the traditional bakery post intervention. In both bakeries, the total particulate matter size fraction consisted predominantly of particles with an aerodynamic diameter lower than 1 µm and greater than 10 µm. Conclusion. Further studies are needed to plan more effective intervention measures supplemented by technical control methods in both bakeries.

Prevention of baker's asthma

PURPOSE OF REVIEW

Baker's allergy and asthma continue to represent an important contributor of occupational asthma globally. This review identified recent studies related to the prevention of baker's allergy and asthma.

RECENT FINDINGS

Studies with respect to regulatory exposure standards, workplace control measures aimed at reduction of flour dust exposures, surveillance programmes (exposure monitoring, medical surveillance) and workplace information, education and training programmes were identified.

SUMMARY

Detailed knowledge on risk factors and detection methods to assess exposure and early identification of high-risk workers exist, but workplace control measures remain sub-optimal because they are rarely multifaceted. This is compounded by the lack of health-based exposure standards globally. Exposure level monitoring and medical surveillance are integral to assessing effectiveness of preventive strategies. Triage systems for optimizing the efficiency of medical surveillance programmes show promise, but need replication in different contexts. Future studies need to focus on evaluating the relevance and quantification of peak exposures in increasing risk; developing standardized respiratory questionnaires for medical surveillance; and further exploration of serial fractional exhaled nitric oxide (FeNO) measurements as an adjunct to allergic sensitization for the early identification of baker's asthma and assessing the long-term impact of interventions.

Assessment of the Level of Organic Dust and Mould Spores in the Work Environment of Baker

Aim:

This study was conducted to determine the level of fungal contamination of the air in bakeries to assess health hazards for workers.

Materials and Methods:

Six bakeries producing traditionally baked goods were selected for the study. After a background survey, samples of exhaled air were collected to test for fungal aerosols. The inhalable and respirable fraction in the bakery air environment was measured by the gravimetric method.

Statistical Analysis Used:

All data analyses were performed using Statistica software (v 8.0).

Results:

The mean concentration of fungi and particles in the bakeries did not exceed the recommended levels. The air in the bakeries had a low level of microbial contamination. The identified fungi included biological agents from hazard group 2.

Conclusions:

Proper employee training and the introduction of preventive measures (including both individual and group protection) can significantly reduce employees’ exposure and thus their occupational risk.

Occupational Exposure to Flour Dust. Exposure Assessment and Effectiveness of Control Measures

The adverse effects associated with exposure to flour dust have been known since the 1700s. The aim of the study was to assess the occupational exposure to flour dust in Italian facilities, identify the activities characterized by the highest exposure, and provide information to reduce workers’ exposure. The study was performed in different facilities such as flourmills (n = 2), confectioneries (n = 2), bakeries (n = 24), and pizzerias (n = 2). Inhalable flour dust was assessed by personal and area samplings (n = 250) using IOM (Institute of Occupational Medicine) samplers. The results showed personal occupational exposure to flour dust over the American Conference of Governmental Industrial Hygiene (ACGIH) and the Scientific Committee on Occupational Exposure Limit (SCOEL) occupational limits (mean 1.987 mg/m³; range 0.093–14.055 mg/m³). The levels were significantly higher for dough makers in comparison to the dough formers and packaging area subjects. In four bakeries the industrial hygiene surveys were re-performed after some control measures, such as installation of a sleeve to the end of pipeline, a lid on the mixer tub or local exhaust ventilation system, were installed. The exposure levels were significantly lower than those measured before the introduction of control measures. The exposure level reduction was observed not only in the dough making area but also in all bakeries locals.

A scoping review to identify strategies that work to prevent four important occupational diseases

BACKGROUND

Despite being largely preventable, many occupational diseases continue to be highly prevalent and extremely costly. Effective strategies are required to reduce their human, economic, and social impacts.

METHODS

To better understand which approaches are most likely to lead to progress in preventing noise-related hearing loss, occupational contact dermatitis, occupational cancers, and occupational asthma, we undertook a scoping review and consulted with a number of key informants.

RESULTS

We examined a total of 404 articles and found that various types of interventions are reported to contribute to occupational disease prevention but each has its limitations and each is often insufficient on its own. Our principal findings included: legislation and regulations can be an effective means of primary prevention, but their impact depends on both the nature of the regulations and the degree of enforcement; measures across the hierarchy of controls can reduce the risk of some of these diseases and reduce exposures; monitoring, surveillance, and screening are effective prevention tools and for evaluating the impact of legislative/policy change; the effect of education and training is context-dependent and influenced by the manner of delivery; and, multifaceted interventions are often more effective than ones consisting of a single activity.

CONCLUSIONS

This scoping review identifies occupational disease prevention strategies worthy of further exploration by decisionmakers and stakeholders and of future systematic evaluation by researchers. It also identified important gaps, including a lack of studies of precarious workers and the need for more studies that rigorously evaluate the effectiveness of interventions.

Asthma Symptoms in Bakeries at Parakou, Benin

Background and Objectives. There is a dearth of information on asthma among bakers in low-income settings. The objectives of this study were to determine (i) the prevalence of asthma symptoms, (ii) factors associated with probable occupational asthma (OA), and (iii) work habits that might lead to a dusty workplace environment, Parakou, Benin. Materials and Methods. This was a mixed methods (cross-sectional quantitative and qualitative) study carried out between March and September 2018.

Assessing the health impact of interventions for baker's allergy and asthma in supermarket bakeries: a group randomised trial

PURPOSE

To assess the impact of an intervention for baker's allergy and asthma in supermarket bakeries.

METHODS

A group randomised trial conducted in 31 bakeries (n = 337 bakers) that were randomly assigned to one of two intervention groups (n = 244 bakers) and a control group (n = 93 bakers). Health data collected prior to and 1-year after the intervention included information obtained from an ECRHS questionnaire; tests for atopy and serum-specific IgE to cereal flours; fractional exhaled nitric oxide (FeNO). Data from the two intervention groups were combined to form one intervention group for purposes of the statistical analysis.

RESULTS

At 1 year of follow-up, the incidence and level of decline of work-related ocular-nasal and chest symptoms, sensitisation status and elevated FeNO (FeNO > 25 ppb) was similar in both intervention and control groups. The mean FeNO difference was also similar across both groups (2.2 ppb vs 1.7 ppb, p = 0.86). In those with FeNO > 25 ppb at baseline, the decline was greater in the intervention compared to control group (16.9 ppb vs 7.7 ppb, p = 0.24). Multivariate logistic regression models (adjusting for smoking, baseline sensitisation to cereal flour, baseline FeNO > 25 ppb) did not demonstrate an appreciable FeNO decline (≥ 10%) in the intervention compared to control group. However, stratification by the presence of work-related ocular-nasal symptoms in bakers at baseline demonstrated a significant FeNO decline (≥ 10%) in the intervention compared to the control group (OR 3.73, CI 1.22-11.42).

CONCLUSION

This study demonstrates some evidence of an intervention effect on FeNO 1 year after an intervention, particularly in bakers with work-related ocular-nasal symptoms.

Food processing and occupational respiratory allergy- An EAACI position paper

Occupational exposure to foods is responsible for up to 25% of cases of occupational asthma and rhinitis. Animal and vegetable high-molecular-weight proteins present in aerosolized foods during food processing, additives, preservatives, antioxidants, and food contaminants are the main inhalant allergen sources. Most agents typically cause IgE-mediated allergic reactions, causing a distinct form of food allergy (Class 3 food allergy). The allergenicity of a food protein, allergen exposure levels, and atopy are important risk factors. Diagnosis relies on a thorough medical and occupational history, functional assessment, assessment of sensitization, including component-resolved diagnostics where appropriate, and in selected cases specific inhalation tests. Exposure assessment, including allergen determination, is a cornerstone for establishing preventive measures. Management includes allergen exposure avoidance or reduction (second best option), pharmacological treatment, assessment of impairment, and worker's compensation. Further studies are needed to identify and characterize major food allergens and define occupational exposure limits, evaluate the relative contribution of respiratory versus cutaneous sensitization to food antigens, evaluate the role of raw versus cooked food in influencing risk, and define the absolute or relative contraindication of patients with ingestion-related food allergy, pollinosis, or oral allergy syndrome continuing to work with exposure to aerosolized food allergens.

Gluten sensitivities and the allergist: Threshing the grain from the husks

"Gluten sensitivity" has become commonplace among the public. Wheat allergy (WA) and celiac disease (CD) are well-defined entities, but are becoming a fraction of individuals following a gluten-free diet (GFD). Wheat allergy has a prevalence of <0.5%. Wheat, specifically its omega-5 gliadin fraction, is the most common allergen implicated in food-dependent, exercise-induced anaphylaxis. CD is a non-IgE hypersensitivity to certain cereal proteins: gluten in wheat, secalin in rye, hordein in barley, and to a lesser extent avenin in oat. It is a rare disease, with an estimated prevalence that varied widely geographically, being higher in Northern Europe and the African Saharawi region than in South-East Asia. In addition to suggestive symptoms, serologic testing has high diagnostic reliability and biopsy is a confirmatory procedure. Patients with CD have extra-intestinal autoimmune comorbid conditions more frequently than expected. A third entity is nonceliac gluten sensitivity, which has been created because of the increasing number of subjects who claim a better quality of life or improvement of their variety of symptoms on switching to a GFD. The phenomenon is being fueled by the media and exploited by the industry. The lack of a specific objective test has been raising substantial controversy about this entity. Allergists and gastroenterologists need to pay attention to the multitudes of individuals who elect to follow a GFD. Many such subjects might have WA, CD, or another illness. Providing them with appropriate evaluation and specific management would be of great advantages, medically and economically.

Cytotoxic and Inflammatory Potential of Air Samples from Occupational Settings with Exposure to Organic Dust

Organic dust and related microbial exposures are the main inducers of several respiratory symptoms. Occupational exposure to organic dust is very common and has been reported in diverse settings. In vitro tests using relevant cell cultures can be very useful for characterizing the toxicity of complex mixtures present in the air of occupational environments such as organic dust. In this study, the cell viability and the inflammatory response, as measured by the production of pro-inflammatory cytokines tumor necrosis factor-α (TNFα) and interleukin-1 β (IL-1β), were determined in human macrophages derived from THP-1 monocytic cells. These cells were exposed to air samples from five occupational settings known to possess high levels of contamination of organic dust: poultry and swine feed industries, waste sorting, poultry production and slaughterhouses. Additionally, fungi and particle contamination of those settings was studied to better characterize the organic dust composition. All air samples collected from the assessed workplaces caused both cytotoxic and pro-inflammatory effects. The highest responses were observed in the feed industry, particularly in swine feed production. This study emphasizes the importance of measuring the organic dust/mixture effects in occupational settings and suggests that differences in the organic dust content may result in differences in health effects for exposed workers.

Bakers' exposure to flour dust

We aimed to characterize bakers' personal exposure to airborne flour dust with respect to the health-related aerosol fractions inhalable, extrathoracic, and thoracic dust, and to examine possible production-related determinants of dust exposure. Sixty-eight bakers from 7 bakeries in Bergen, Norway (2009-2012) participated in the exposure assessment, comprising full-shift personal samples of inhalable dust (n = 107) and thoracic dust (n = 61). The relation between possible determinants and exposure was estimated using mixed effects models, while associations between the various aerosol fractions across task groups and type of bakeries were described by Pearson's correlation coefficients. Bakers' overall geometric mean personal exposure to inhalable, extrathoracic, and thoracic dust were 2.6 mg/m³ (95% CI: 2.0, 3.2), 2.2 mg/m³ (95% CI: 1.9, 2.7), and 0.33 mg/m³ (95% CI 0.3, 0.4), respectively. A total of 29% of the measurements of inhalable dust were above the Norwegian Occupational Exposure Limit of 3 mg/m³. The exposure variability of inhalable dust could not be explained by any of the examined production-related determinants, while the daily production volume explained 18% of the variance in thoracic dust exposure. Overall, the thoracic dust represented 15% of the inhalable dust, being rather stable across the production-related determinants. The overall correlation between inhalable and thoracic dust was nevertheless moderate (r = 0.52, p < 0.001), with the highest correlation for craft bakers (r = 0.62) and no correlation during dough forming (r = 0.01). Bakers are exposed to flour dust at a level that most likely represents an excess risk of developing chronic diseases of the respiratory system, and a decrease of present exposure level is imperative. Extrathoracic dust-likely the most relevant sub-fraction in respect to flour-induced sensitization and occupational rhinitis-represented the main proportion of the measured inhalable dust. The variation in correlation coefficients between the dust fractions across bakery types and task groups underlines the need of more knowledge about how these aerosol fractions are distributed across the production process and bakery types.

Feedback on Measured Dust Concentrations Reduces Exposure Levels Among Farmers

BACKGROUND

The high burden of exposure to organic dust among livestock farmers warrants the establishment of effective preventive and exposure control strategies for these workers. The number of intervention studies exploring the effectiveness of exposure reduction strategies through the use of objective measurements has been limited.

OBJECTIVE

To examine whether dust exposure can be reduced by providing feedback to the farmers concerning measurements of the exposure to dust in their farm.

METHODS

The personal dust levels of farmers in 54 pig and 26 dairy cattle farms were evaluated in two measurement series performed approximately 6 months apart. Detailed information on work tasks and farm characteristics during the measurements were registered. Participating farms were randomized a priori to a control (n = 40) and an intervention group (n = 40). Shortly after the first visit, owners of intervention farms only received a letter with information on the measured dust concentrations in the farm together with some general advises on exposure reduction strategies (e.g. use of respirators during certain tasks). Relationships between measured dust concentrations and intervention status were quantified by means of linear mixed effect analysis with farm and worker id as random effects. Season, type of farming, and work tasks were treated as fixed effects. Changes in exposure over time were explored primarily at a farm level in models combined, as well as separate for pig and cattle farmers.

RESULTS

After adjustment for fixed effects, an overall reduction of 23% in personal dust exposures was estimated as a result of the intervention (P = 0.02). Exposure reductions attributable to the intervention were similar across pig and cattle farmers, but statistically significant only for pig farmers. Intervention effects among pig farmers did not depend on the individuals' information status; but among cattle farmers a significant 48% reduction in exposure was found only among individuals that reported to have been informed. No systematic differences in changes over time considering the use of respiratory protection between the intervention and control groups were observed.

CONCLUSION

The results of the present study suggest reductions between 20 and 30% in personal exposure to inhalable dust to be feasible through simple information provided to the farm owners regarding actual levels of exposure together with instructions on basic measures of prevention. The exact reasons for these effects are unclear, but likely they involve changes in behavior and working practices among intervention farmers.