Flour Exposure Research Articles

The impact of years of training and possible technical, procedural, and individual risk factors for the development of atopic symptoms among bakery and confectionery trainees.

Occupational asthma is commonly observed in bakers and confectioners. Endogenous and exogenous risk factors contribute to bakers' asthma. A heightened awareness of this and early diagnosis can be helpful in terms of prevention. The aim of the study was to identify a temporal relationship between the years of training, as well as possible technical, procedural, and individual risk factors for the development of flour-exposure related atopic symptoms such as rhinitis, cough, and rash in young professionals. 127 bakers and confectioner trainees were observed over a one-year period. Two questionnaires served as test instruments. It was investigated whether the rates of atopic symptoms change over the course of a school year and which conditions in the workplace could be responsible for this. Descriptive statistics were used to answer the research questions concerning flour exposure and symptom rates. The Pearson-Chi-Square test was used for testing statistical differences between different groups (e.g. year of training, working conditions). An increase in rates of self-reported rhinitis, coughing, and rashes throughout the duration of traineeship was shown (e.g. rhinitis of bakers at work: 0% in the first year of training, 20% in the second and 33% in the third year of training). The installation of vapour extraction systems and low-dust transfer of baking agents led to fewer symptoms in the workplace (30% of participants with rhinitis symptoms worked with no installed vapour extraction systems). A medical history of atopy was positively correlated with the occurrence of symptoms. To prevent the development of asthma in bakers, methods to improve occupational health and safety should be developed. Creating low dust working conditions e.g., due to the use of vapour extraction systems should be considered.

Flour exposure, sensitization and respiratory health among Alberta trainee bakers.

Sensitization to allergens encountered in baking, and allergic disease including asthma and rhinitis, is recognized. Attempts to reduce this risk have been instituted in some workplaces, but awareness remains low. This study aimed to quantify the current risk among Alberta bakers. To estimate the onset of sensitization to bakery allergens and allergic disease among trainee bakers at the outset of their career. Trainees attending one of the two bakery programmes were recruited between 2015 and 2018. At entry, an interview was held and spirometry and skin prick tests were performed. Participants were contacted every 6 months by telephone or online interview for 3 years to update work and health information. An exit interview was completed between 2018 and 2019 for all who could be contacted. Exposure was estimated using collected work history and a job exposure matrix was prepared for this study. A total of 220 individuals participated in the entry interview, 204 completed one or more periodic interviews and 113 completed the exit interview. Six who completed exit testing developed new sensitization to bakery antigens, an incidence of 2.49/100 person-years. Positive skin prick tests for bakery antigens were associated with bread making. Rhinitis symptoms were associated with total flour dust and new-onset rhinitis to months in trade. New-onset asthma was related to cumulative exposure to flour improvers. Trainee bakers in Alberta remain at risk of sensitization and occupational respiratory disease.

Exposure to additives or multigrain flour is associated with high risk of work-related allergic symptoms among bakers

ObjectivesWheat flour exposure in bakers can elicit respiratory and skin symptoms. Scarce data are available on the prevalence of such conditions in bakers. We investigated the prevalence of work-related rhinitis,...

Estimation and Validation of Flour Exposure in Bakeries in Alberta, Canada.

In epidemiological studies of work-related ill-health only current exposures can, at best, be measured. Previous exposures may be estimated using contemporaneous hygiene records or published data. This study aimed to create a job exposure matrix for exposure in bakers for use in an ongoing cohort study. A systematic review was conducted of English language publications on exposures in bakeries. All publications that appeared to contain quantitative measures of exposure to flour dust, wheat allergen, or fungal α-amylase were read independently by two investigators and relevant data extracted. A third investigator reviewed these data and publications were retained that reported full-shift exposures to inhalable dust, wheat allergen, or α-amylase, and for which geometric means (GMs) were given or could be estimated. For each study, the number of sampling results contributing to each GM was recorded together with information on task, bakery size, product, filter type, sampling head, the country in which the study was conducted, and the estimated year of sampling. Multivariable models were elaborated for each exposure using a linear mixed effects approach. The predictive capacity of the model for inhaled particles was tested against samples collected in eight Alberta bakeries. The capacity of exposure intensity, estimated from each of the three models, to predict sensitization was tested against skin prick testing (SPT) for bakery allergens in bakers currently employed in Alberta. One thousand three hundred and ninety-seven publications were identified through the systematic search, of which 27 had data used to create one or more of the predictive models. Weighted GMs were used as outcome variables. For inhalable dust, task, bakery size, type of sampling head, and year of sampling contributed to the final model. For wheat allergen and α-amylase, task, bakery size, sampling head, and year of sampling again contributed. Product (bread rather than confectionary or mixed products) was also important in these two latter measures. The model for inhalable dust was used to predict the concentration in 33 samples from Alberta bakeries. Overall, 91% of observed samples had 95% confidence intervals (CIs) overlapping the 95% CIs of the predicted values. A model including the Alberta samples found no effect attributable to Alberta provenance. Using this model for inhalable dust and the models developed solely from the literature for wheat allergen and α-amylase, a positive SPT for bakery allergens in 57 bakers recruited for this study was significantly related to log cumulative exposure for each of the three outcome variables and to log exposure intensity for wheat allergen and α-amylase. The exposure models developed from the literature provide useful estimates of exposure. Calibration of the models against locally collected samples may be useful for countries poorly represented in the modeling dataset.

Airway exposure initiates peanut allergy by involving the IL-1 pathway and T follicular helper cells in mice

Little is currently known regarding the immunologic mechanism(s) that initiate peanut allergy. Notably, peanut proteins have been detected in house dust, and their levels correlate with peanut allergy prevalence. This study aimed to develop a new mouse model for peanut allergy and to investigate the immunologic mechanisms involved in peanut allergen sensitization. To mimic environmental exposure, naive mice were exposed to peanut flour by inhalation for up to 4weeks. We then analyzed serum levels of IgE antibody and challenged mice with peanut proteins. Immunological mechanisms involved in sensitization were analyzed using cytokine reporter mice, an adoptive cell transfer model, and gene knockout mice. When exposed to peanut flour by inhalation, both BALB/c and C57BL/6 mice developed peanut allergy, as demonstrated by the presence of peanut-specific IgE antibodies and manifestation of acute anaphylaxis on challenge. Alarge number of follicular helperT (Tfh) cells were also detected in draining lymph nodes of allergic mice. These cells produced IL-4 and IL-21, and they more robustly promoted peanut-specific IgE production than Th2 cells did. Genetic depletion of Tfh cells decreased IgE antibody levels and protected mice from anaphylaxis, without affecting Th2 cells. Furthermore, peanut flour exposure increased lung levels of IL-1α and IL-1β, and mice deficient in the receptor for these cytokines showed a significant decrease in Tfh cells compared with in wild-type mice. Tfh cells play a key role in peanut allergy, and the IL-1 pathway is involved in the Tfh response to peanut allergen exposure.

Component-resolved diagnosis of baker's allergy based on specific IgE to recombinant wheat flour proteins

Sensitization to wheat flour plays an important role in the development and diagnosis of baker's asthma. We evaluated wheat allergen components as sensitizers for bakers with work-related complaints, with consideration of cross-reactivity to grass pollen. Nineteen recombinant wheat flour proteins and 2 cross-reactive carbohydrate determinants were tested by using CAP-FEIA in sera of 101 bakers with wheat flour allergy (40German, 37 Dutch, and 24 Spanish) and 29 pollen-sensitized control subjects with wheat-specific IgE but without occupational exposure. IgE binding to the single components was inhibited with wheat flour, rye flour, and grass pollen. The diagnostic efficiencies of IgE tests with single allergens and combinations were evaluated by assessing their ability to discriminate between patients with baker's allergy and control subjects based on receiver operating characteristic analyses. Eighty percent of bakers had specific IgE levels of 0.35 kUA/L or greater and 91% had specific IgE levels of 0.1 kUA/L or greater to at least one of the 21 allergens. The highest frequencies of IgE binding were found for thiol reductase (Tri a 27) and the wheat dimeric α-amylase inhibitor 0.19 (Tri a 28). Cross-reactivity to grass pollen was proved for 9 components, and cross-reactivity to rye flour was proved for 18 components. Acombination of IgE tests to 5 components, Tri a 27, Tri a 28, tetrameric α-amylase inhibitor CM2 (Tri a 29.02), serine protease inhibitor-like allergen (Tri a 39), and 1-cys-peroxiredoxin (Tri a 32), produced the maximal area under the curve (AUC= 0.84) in receiver operating characteristic analyses, but this was still lower than the AUC for wheat- or rye flour-specific IgE (AUC= 0.89 or 0.88, respectively). Component-resolved diagnostics help to distinguish between sensitization caused by occupational flour exposure and wheat seropositivity based on cross-reactivity to grass pollen. For routine diagnosis of baker's allergy, however, allergen-specific IgE tests with whole wheat and rye flour extracts remain mandatory because of superior diagnostic sensitivity.

Could Sputum Eosinophilia Act as a Predictive Test for Diagnosis of High Risk Bakery Workers to Asthma?

Background: Occupational flour inhalation has been a culprit in the start of several pulmonary diseases such as asthma. We examined the relationship between occupational wheat flour inhalation in bakery and supermarket employees with pulmonary functions, respiratory symptoms, and sputum eosinophilia to determine hyper-responsiveness in a cross-sectional study in Iran. Methods: 122 subjects from traditional bakeries and 137 subjects from supermarket employees were enrolled in the study. Flour exposure concentrations, respiratory signs, sputum analysis, and respiratory volumes and capacities were measured based on the standard methods. Results: Respirable concentration of flour in the bakery workers was two- to four-fold of ACGIH’s threshold limit value in which bread-bakers with 2.2 mg/m3 experienced maximum exposures. The supermarket employees were not exposed to flour dust. The respiratory volumes in both bakery and supermarket employees were in the normal range. However, the median of voluminal percentage in bakery workers except Forced Vital Capacity (FVC) decreased (p p < 0.05). In addition, we observed increased respiratory symptoms in the bakery workers, again more prevalent in the bread-bakers. There was a significant correlation between flour exposure concentration and sputum eosinophilia in which the percentage of eosinophilia in the bread-bakers was more than other bakery and supermarket employees. Although there were reductions in the respiratory volumes, the results indicated no obstructive spirometric pattern. Conclusions: Sputum eosinophilia might be a suitable screening method to detect airway hyper-responsiveness in workers exposed to known asthmogens.

Asthma and occupation in the 1958 birth cohort

ObjectiveTo examine the association of adult onset asthma with lifetime exposure to occupations and occupational exposures.MethodsWe generated lifetime occupational histories for 9488 members of the British 1958 birth cohort up...

Impact of worker education on respiratory symptoms and sensitization in bakeries

Flour exposure is known to cause significant respiratory problems. To investigate the development of work-related sensitization, the period between first exposure and the development of symptoms (latent period) and the impact of workplace training programmes on respiratory health in plant bakers. Two hundred and sixty-four bakers were investigated by assessing work-related respiratory symptoms and latent period before symptoms/sensitization, spirometry and testing for an array of workplace-specific IgE. There was a significant relationship between the presence of work-related respiratory symptoms and flour dust allergen-specific IgE. Latent periods varied widely: median for work-related nasal symptoms 36 months, cough 42 months and chest tightness 120 months. Latent periods were shorter for workers with evidence of flour sensitization (work-related wheeze: mean 13 months with sensitization, 97 months without, P < 0.05, work-related nasal symptoms, respectively; mean 19 months, 71 months, P < 0.01). Those warned of the health implications of flour dust had less work-related wheeze (warned; 1%, not warned 11%, P < 0.05). There was an excess of work-related symptoms and work-related-specific IgE combined in those who had not been warned of these health implications (12 versus 1%, P <0.01). Reporting of 'being warned' of potential health implications from breathing flour dust protected strongly against the reporting of important health end points. Latent periods for the development of work-related symptoms varied widely. Simple health messages, which may be overlooked in worker training programmes, can have significant benefits for worker health in the bakery population.

Allergic asthma after flour inhalation in subjects without occupational exposure to flours: an experimental pilot study

Cross-reactivity between grass pollen and grain flour allergens is well known, but their significance in apprentice bakers with primary sensitization to grass pollen is not known. Twenty-five subjects with mild asthma (most of them with hay fever), but without prior occupational flour exposure, underwent standardized experimental inhalation challenges with placebo and wheat and rye flours in randomized order on three consecutive days. Sensitization to flours and environmental allergens was assessed by skin prick tests and specific IgE antibodies in sera. IgE inhibition experiments were performed with wheat and rye flours as solid phases, and grass and tree pollen as inhibitors. Five subjects experienced a positive reaction after flour inhalation (responders), whereas 20 subjects did not show such a reaction (non-responders). All responders showed sensitizations to flours, whereas only 25% of the non-responders demonstrated the same sensitization. Specific IgE concentrations to flours, but also to grass and tree pollen, were higher in responders. Inhibition experiments demonstrated cross-reactivity between flours and grass or tree pollen, with higher inhibition rates in responders. Subjects with pronounced sensitizations to grass or tree pollen, but without prior occupational exposure to flours, may experience both sensitization and allergic asthmatic reactions to flours due to cross-reactive grass and tree pollen allergens.

Approaches to the diagnosis and management of occupational asthma amongst UK respiratory physicians

This study aimed to assess the approach to the diagnosis and management of occupational asthma amongst general (non-specialist) respiratory consultants in the UK. A random sample of 100 UK general respiratory physicians were invited to participate, and asked to provide information on their diagnostic approach to a case scenario of a patient with possible occupational asthma relating to flour exposure. Participation rates were 42% for the main part of the study. Less than half of consultants specifically reported they would ask whether symptoms improved away from work, and just over a third mentioned examining the patient. All of those interviewed recommended a chest X-ray, and 98% simple spirometry. Eighty-six per cent suggested measurement of serial peak flows, recorded for between 2 and 8 weeks, with measurements taken half-twelve hourly. Less than half advocated a specific flour allergy test, and almost one-quarter (23%) would not perform any immunological test at all. Once a diagnosis of occupational asthma was confirmed, less than two-thirds of those interviewed commented they would recommend some form of exposure reduction, and only 28% specifically stated they would offer compensation advice. The diagnosis of occupational asthma by general respiratory physicians within the UK lacks standardisation, and in some cases falls short of evidence-based best practise.

Occupational asthma by grass pea used industrial processing by parquet

although grass pea belongs to the leguminoseae family, allergic reactions to its flour have rarely been described. Clinical and immunological studies were performed to confirm a type I hypersensitivity mechanism in a case of occupational asthma to grass pea flour exposure, used in the industrial processing of parquet. occupational asthma was diagnosed according to patient history, PEFR monitoring and a specific bronchial challenge test. Skin prick test with an aqueous grass pea flour extract, specific IgE determinations (CAP assay) and IgE immunoblot tests were performed. skin prick test with the extract showed a positive immediate response, and negative response in controls. Specific IgE to grass pea was positive (9.57 KU/l). Immunoblotting demonstrated the presence of specific serum IgE that recognized 3 proteins in the extract (MW 46, 32 and 28 kDa). PEFR monitoring showed positive results. Bronchial challenge test with the extract elicited an isolated immediate response. as far as we know this is the first time that IgE mediated occupational asthma caused by grass pea is reported and it is also the first time that its allergens are characterized. Grass pea flour might constitute a relevant occupational allergen in this unreported source of exposure in parquet manufacturers.

Respiratory symptoms and wheat flour exposure: a study of flour millers.

The objective of this study was to determine the prevalence of respiratory symptoms and their relationship to sensitization to wheat flour allergens and fungal amylase, in a group of workers from the UK flour milling industry. A cross-sectional study was used to evaluate symptoms, using a structured interview technique, and sensitization, using skin prick test findings, from 679 employees in flour milling and packing operations at 18 flour mills. A total of 147 workers (147/679, 22%) described upper respiratory tract symptoms of some kind. In the majority (139/147, 95%) these symptoms were of an occasional or transitory nature and were related to short-term exposures to high levels of dust. Three individuals (3/679, 0.4%) were identified whose symptoms were thought to be the result of allergy to wheat flour. The prevalence of positive skin prick tests to wheat flour allergens and to fungal amylase was 1.2% (8/678) and 0.9% (6/678), respectively. Measurements of total inhalable dust exposure for personnel exposed to flour dust were taken at 10 of the sites (116 samples). For production personnel the levels were typically between 1 and 10 mg/m3 (8-h time weighted average), with a median of 6.2 mg/m3. Hygiene operatives had appreciably higher exposure than production personnel, with a median of 18.7 mg/m3. Overall, 43% (50/116) of all samples exceeded 10 mg/m3 (8-h time weighted average). The findings suggest that the risk of sensitization to wheat flour allergens from current dust exposures in flour mills is very low. Wheat allergy was responsible in only a small proportion of the total who had respiratory symptoms. The principal causation of symptoms experienced by the workforce was considered to be a non-specific irritant effect related to short-term exposures to high levels of total inhalable dust.

Respiratory sensitization to konjac flour in guinea pigs

Medical reports linking asthma and occupational exposure to airborne powder produced during the manufacture of konjac flour have been reported in the literature. This study was conducted to investigate whether exposure to food grade konjac flour, which is the end product of the manufacturing process, could produce respiratory hypersensitivity using an animal bioassay developed by Karol et al. (Karol, Y., Ioset, H.H., Riley, E.J., Alarie, Y.C., 1978. Am. Ind. Hyg. Assoc. J. 39, 546–556). Groups of guinea pigs were randomly assigned to a negative control, a konjac flour exposure group, or a positive control group exposed to trimellitic anhydride (TMA). The study design included five consecutive days of inhalation induction exposures followed by three inhalation challenge exposures on days 19, 26 and 40. Positive control guinea pigs were exposed to 98 mg/m 3 TMA during the induction exposures and 57–67 mg/m 3 TMA during the challenge exposures. The mean (±S.D.) konjac flour concentration during the induction exposures was 111±8.3 mg/m 3 and the exposure concentrations of konjac flour during the challenge exposures ranged from 50 to 68 mg/m 3. The criteria used to define respiratory tract sensitization (an increase in respiratory rate of 36% and a change in the respiratory waveform) were met by 25% of the animals at each challenge in the konjac flour group. In addition, a few animals responded with slightly lower increases in respiratory frequency and a change in waveform suggestive of a slight pulmonary hypersensitivity response. Guinea pigs that responded during the first challenge also responded during subsequent challenges. No changes in respiratory rate or waveform were noted in animals assigned to the negative control group when challenged with konjac flour. The results of this study indicate that respiratory hypersensitivity to food grade konjac flour can be induced in guinea pigs following repeated inhalation exposure. Therefore, proper engineering controls or personal protection equipment should be utilized to prevent respiratory sensitization in those who may be occupationally exposed to food grade konjac flour.

Measurement of airborne flour exposure with a monoclonal antibody-based immunoassay.

The development of simple and standardised methods to measure airborne levels of workplace biological allergens is an important step in reducing the incidence of occupational asthma. Such a method would be useful for measuring wheat flour allergens which cause asthma in bakers. Measurement of allergen per se rather than total dust enables exposure to be better defined. Monoclonal antibodies were produced, their specificity analysed by immunoblotting and then used to affinity-purify a putative flour allergen. The importance of this protein as an allergen was tested by RAST using sera from allergic bakers and it was identified by N-terminal sequencing. Suitable monoclonal antibodies were chosen to develop an enzyme-linked immunosorbent assay. Commercial baking flours and personal airborne dust samples were analysed using the immunoassay. A sensitive and specific monoclonal antibody-based enzyme-linked immunosorbent assay was developed to measure a wheat alpha-amylase inhibitor. The wheat alpha-amylase inhibitor content of bulk wheat flours was 0.124% (95% confidence limits 0.083-0.164%) and airborne levels in bakeries had a geometric mean of 744 ng/m3 (95% confidence limits 371-1,496 ng/m3). This assay is suitable for widespread use as the monoclonal antibodies and standards are well defined and potentially infinitely available. The assay therefore offers distinct advantages over those exposure assessment methods currently in use. Comparable results would be obtained by different investigators over a prolonged time period. The assessment of flour allergen exposure and the relationship with clinical response could then be investigated using a multi-centered approach.

Flour protein antigens in occupational flour hypersensitivity.

Thirty serum samples from clinical cases of flour hypersensitivity were analyzed for wheat or rye flour protein antibodies. The patients included 20 bakers and 10 others who also had occupational flour exposure. Twenty-three cases had antiflour antibodies which recognized antigens other than control sera in the flour protein patterns. The immunologic response of individual cases seemed very variable in view of the numerous differences between the cases in the antigen-antibody reactions. For the practical purposes, the flour protein antigens were divided in three groups, i.e., those larger than 80 kDa, those between 80 and 50 kDa and those smaller than 50 kDa. Cases with flour-induced dermatitis (n = 8) showed sensitization towards antigens in all size classes while those with rhinitis or asthma showed more antigens with a molecular weight less than 50 kDa. The test offers a possibility to independently verify an exposure to flour while it does not substitute for the conventional immunologic diagnostic tests.