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

Carla Viegas,Liliana Aranha Caetano,Abdul Kadir,Robert Kosicki,Susana Viegas,Beatriz Almeida,Gerard T A Fleming,Ann Marie Coggins,Magdalena Twarużek,Anita Quintal Gomes

doi:10.3390/microorganisms8010118

Abstract

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.

Highlights

Flour, the basic ingredient in an array of bread and bakery products, is a complex organic dust containing allergens and antigenic particles from constituent cereals, such as wheat, oat, rye, rice, or corn [1]
The pizzeria restaurant consisted of two work areas, Microorganisms 2020, 8, 118 one area included the raw ingredients store, where materials were added to a kneading machine to produce the pizza or bread dough, which was transferred to a second area where it was kneaded by hand and used to prepare pizzas, breads or pastries
The results showed that at least one mycotoxin was found in eight samples, two mycotoxins in six samples, and three mycotoxins were found in six samples

Summary

Introduction

The basic ingredient in an array of bread and bakery products, is a complex organic dust containing allergens and antigenic particles from constituent cereals, such as wheat, oat, rye, rice, or corn [1]. Along with other raw ingredients commonly used in baking, baker’s yeast, bread improvers, and flour can provide an ideal substrate for microbial growth, and can generate high levels of bioaerosols during processing [2,3]. Occupational exposures in this sector can lead to the development of conjunctivitis; contact dermatitis; and debilitating occupational respiratory diseases, including flour induced rhinitis and “baker’s asthma”, the latter of which is one of the most common work-related respiratory diseases. Occupational exposure to azole-resistant strains of fungi, such as Aspergillus sp., and toxigenic substances, such as mycotoxins, have been detected in cereals such as wheat, rye, oats, and corn, and are of concern in this sector [2], especially with reports of the increasing prevalence of azole-resistant strains of fungal species in clinical settings [12]

Objectives

Methods

Results

Discussion

Conclusion