Bakers' exposure to flour dust

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.

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.

Occupational Exposures to Organic Dust in Irish Bakeries and a Pizzeria Restaurant

For decades, occupational exposure to flour dust has been linked to a range of respiratory diseases, including occupational asthma, thought to result from exposure to fungi present in the flour. Antifungal resistance is of increasing prevalence in clinical settings, and the role of occupational and environmental exposures, particularly for specific fungal species, is of concern. Occupational exposure to flour dust can occur in a range of occupational settings, however, few studies have focused on restaurant workers. The objective of this study was to measure occupational exposure to flour and microbial contamination, including azole resistance screening, in two small commercial bakeries and in a pizzeria. Personal full shift inhalable dust measurements were collected from workers, and were analyzed for inhalable dust and fungi, bacteria, azole resistance, and mycotoxins. Samples of settled dust were collected, and electrostatic dust cloths (EDC) were deployed and analyzed for microbial contamination, including azole resistance screening, and mycotoxins. Geometric mean exposures of 6.5 mg m^-³ were calculated for inhalable dust, however, exposures of up to 18.30 mg m^-³ were measured-70% of personal exposure measurements exceeded the occupational exposure limit for flour dust of 1.0 mg m^-³. The air and EDC fungal counts were similar to those reported in previous studies for similar occupational environments. The fungi were dominated by Penicillium genera, however Aspergillus genera, including Fumigati and Flavi sections, were observed using culture-based methods, and the Fumigati section was also observed by molecular tools. Both Aspergillus sections were identified on the azole resistance screening. Mycotoxins were also detected in the settled dust samples, dominated by deoxynivalenol (DON). The role of environmental exposure in both the development of antimicrobial resistance and the total mycotoxin body burden is a growing concern; therefore, the presence of azole-resistant fungi and mycotoxin contamination, although low in magnitude, is of concern and warrants further investigation.

Occupational exposures of flour dust and airborne chemicals at bakeries in Taiwan

Walk-through surveys were carried out for bakeries in this study to determine the environmental characteristics of bakeries in Taiwan. Questionnaires were administrated to discover whether job-related asthma-like symptoms occurred among workers. Air sampling and analysis were also performed. The results show that the levels of inhalable flour dust ranged from 0.01-0.83 mg m^-3 with an average of 0.27 mg m^-3. Among the samples collected, 23% of them had concentrations higher than the ACGIH TLV-TWA (0.5 mg m^-3), which indicated that inhalable flour dust was an important air pollutant for bakery workers in Taiwan. Airborne chemicals such as diacetyl, acetoin, 2,3-pentanedione, 2,3-hexanedione, 2,3-heptanedione, furfural, and acetaldehyde were also found in various levels in this study. The concentrations of acetaldehyde measured in these bakeries were 37-83 times higher than what have been reported from other studies for residential areas and Chinese restaurants. In addition, the concentrations of total VOCs in the working areas of the bakeries were over 21 times higher than the levels determined in the non-working areas. Based on our results, there appears to be a need to improve the air quality of the working environments of bakeries in Taiwan.

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.

Concentrations and number size distribution of fine and nanoparticles in a traditional Finnish bakery

In bakeries, high concentrations of flour dust can exist and ovens release particles into the air as well. Particle concentrations (mass, number) and number size distribution may vary considerably but the variation is not commonly studied. Furthermore, the role of the smallest size fractions is rarely considered in the exposure assessment due to their small mass. The objectives of this work were to find out how concentrations and number size distribution of fine and nanoparticles vary in a traditional Finnish bakery and to determine the exposure of a dough maker to the nanoparticle fraction of the inhalable dust. Two measurement campaigns were carried out in a traditional, small-scale bakery. Sampling was performed at the breathing zone of the dough maker and three stationary locations: baking area, oven area, and flour depository. Both real-time measurements and conventional gravimetric sampling were conducted. Nanoparticle fraction of the inhalable dust was determined using an IOM sampler with a customized precyclone. Number concentration of fine and nanoparticles, and mass concentrations of both the inhalable dust and nanoparticles were high. The nanoparticle fraction was 9-15% of the inhalable dust at the breathing zone of the dough maker. Different sources, such as ovens and doughnut baking affected the number size distribution. Flour dust contained nanoparticles but most of the fine and nanoparticles were released into the air from the oven operations. However, nanoparticles are not a primary concern in bakeries compared to health effects linked to the large flour particles such as flour-induced sensitization or asthma and development of occupational rhinitis.