Page 1 Health Hazard Evaluation Report 2009-0131-3171 Evaluation of Sensitization and Exposure to Flour Dust, Spices, and Other Ingredients Among Poultry Breading Workers Report No. 2009-0131-3171 April 2013 Elena H

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Health Hazard Evaluation Report 2009-0131-3171

At the time of our evaluation, employees on the hazardous materials team (mainly 

refrigeration and select maintenance employees) were included in the respiratory protection 

program. We did not review the respiratory requirements for the hazardous materials team 

as part of this evaluation. While production employees were not required to wear respiratory 

protection and were not included in the respiratory protection program, some employees used 

NIOSH-approved N95 filtering facepiece respirators voluntarily. We saw some employees 

wearing their filtering facepiece respirators incorrectly. Examples of incorrect filtering 

facepiece respirator use included employees wearing their respirator over a beard guard, 

incorrectly placing the respirator only over their mouth, and using only one strap.

The bread and batter lines were equipped with local exhaust ventilation. However, we saw 

instances where the local exhaust ventilation was not connected to the duct work (Figures 1, 

2, 3, and 4). Local exhaust ventilation was absent from the dispensing hoppers at the point 

where dry ingredients were transferred from paper bags to the dispensing hoppers (Figure 

5). We observed that many of the local exhaust ventilation collection points between the 

breading line machines did not collect all the flour dust, evidenced by dust accumulation 

in the immediate work area (Figure 4). We observed product conveyers that were neither 

enclosed nor equipped with local exhaust ventilation (Figures 3, 4, and 6). On batter and 

bread hoppers and breading machines that were enclosed, access doors were not closed 

(Figure 5 and 7), resulting in dust escaping because of machine vibration.

Table 10. Prevalence of sensitization to breading dust 

components, by atopy

Atopy

P value

Yes (n=81)

No (n=155)

Sensitized to flour dust

Number (%)

47 (58)

19 (12)

< 0.01

Sensitized to wheat

Number (%)

51 (63)

21 (14)

< 0.01

Sensitized to soy

Number (%)

27 (33)

2 (1)

< 0.01

Sensitized to corn

Number (%)

42 (52)

4 (3)

< 0.01

Sensitized to garlic

Number (%)

32 (40)

3 (2)

< 0.01

Sensitized to 

paprika

Number (%)

17 (21)

1 (1)

< 0.01

Sensitized to onion

Number (%)

26 (32)

1 (1)

< 0.01

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Health Hazard Evaluation Report 2009-0131-3171

Figure 1. Disconnected and uncapped local exhaust ventilation duct on line one.

Figure 2. Disconnected and uncapped local exhaust ventilation duct on line one.

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Health Hazard Evaluation Report 2009-0131-3171

Figure 3. Local exhaust ventilation attachment not in use on breader.

Figure 4. Local exhaust ventilation attachment not in use on breader and non-

enclosed product conveyer belt.

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Health Hazard Evaluation Report 2009-0131-3171

Figure 5. Dispensing hopper lid on breading machine.

Figure 6. Unenclosed conveyor belt without local exhaust ventilation and transfer 

point between machines.

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Health Hazard Evaluation Report 2009-0131-3171

We observed employees using poor techniques to transfer dry powdered ingredients, resulting 

in unnecessary exposures to breading dust (Figure 8). For example, some employees 

transferred dry ingredients to overhead hoppers or hoppers in difficult to reach locations. 

This often required them to place their head into the dust cloud generated by the transfer. We 

also observed employees transferring dry powdered ingredients into the hoppers using quick 

movements that generated visible dust clouds. These practices increased exposure to the 

airborne breading dust.

Figure 7. Open enclosure on breading machine.

Figure 8. Employee transferring dry powdered ingredients into a breading machine hopper at breathing 

zone height.

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Health Hazard Evaluation Report 2009-0131-3171

Discussion 

A health hazard existed at this plant from exposure to breading dust. Personal breathing 

zone air sampling showed that employees in almost all areas of the plant had the potential 

for exposure to flour dust levels above the American Conference of Governmental Industrial 

Hygienists (ACGIH®) threshold limit value (TLV®) for flour dust. We compared our 

sampling results to the ACGIH TLV because it is specific to flour dust and was established 

to minimize the potential for wheat flour sensitization. At the time of this evaluation the 

company evaluated employee exposures by comparing them to the less protective OSHA 

PEL for particulates not otherwise regulated. We believe this practice led to the high 

prevalences of sensitization to flour dust, wheat, spices, and other ingredients; and to work-

related asthma symptoms, cough, and rhinoconjunctivitis. Exposures to flour dust in the 

plant must be reduced to prevent adverse health effects and minimize worsening of existing 

symptoms and disease.

The prevalence of sensitization to wheat among the higher-exposure group in this evaluation 

(36%) is higher than that found in studies of bakers (5%–28%) [Houba et al. 1996; Baatjies et 

al. 2010]. The prevalence of sensitization to wheat among participants in the lower-exposure 

group (15%) was within the range found in bakers and higher than in the general population 

(1.2% to 4.1%) [Houba et al. 1996; Gautrin et al. 1997; Biagini et al. 2004]. This is consistent 

with our data showing exposure to flour dust and wheat throughout the plant. 

We placed participants into exposure groups on the basis of our observations of their work, 

a review of historical exposure data collected by the plant, and our professional judgment, 

but we may have misclassified some employees. Additionally, after reviewing our personal 

breathing zone results, we concluded that few, if any, plant employees are unexposed to flour 

dust and other breading ingredients. 

As a result of our classification strategy, although the higher-exposure group had a median 

inhalable flour dust concentration several times higher than the lower-exposure group the 

exposures were overlapping. Moreover, airborne concentrations of inhalable flour dust and 

wheat for the higher-exposure group in our evaluation were much higher and those of our 

lower-exposure group were similar or higher than those found in Belgian bakeries [Bulat et 

al. 2004]. Median inhalable flour dust concentrations in a study of 55 bakeries in the United 

Kingdom were midway between those of our two exposure groups; however, peak exposures 

were much higher in our higher-exposure group [Elms et al. 2005]. Inhalable flour dust and 

wheat concentrations were also much higher than personal breathing zone samples from 

supermarket bread bakers in South Africa, even for the lower-exposure group [Baatjies 

et al. 2010]. Exposures to flour dust occurred throughout the plant, including areas where 

batter or breading mixes were not used. While the inhalable flour dust sampling method is a 

weight gain analysis not specific to flour dust, the presence of wheat allergens on the samples 

confirmed that flour dust was present in those areas. 

While 23 participants reported changing jobs because of respiratory tract or mucous 

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