Mycotoxins and other fungal metabolites in grain dust from Norwegian grain elevators and compound feed mills

Abstract

Employees at grain elevators and compound feed mills are exposed to large amounts of grain dust during work, frequently leading to airway symptoms and asthma. Although the exposure to grain dust, microorganisms, β-1→3-glucans and endotoxins has been extensively studied, the focus on the mycotoxin content of grain dust has previously been limited to one or few mycotoxins. Our objective was therefore to screen settled grain dust from grain elevators and compound feed mills for fungal metabolites by LC/MS-MS and explore differences between work places, seasons and climatic zones. Seventy fungal metabolites and two bacterial metabolites were detected. Trichothecenes, depsipeptides, ergot alkaloids, and other metabolites from Fusarium, Claviceps, Alternaria, Penicillium, Aspergillus, and other fungi were represented. The prevalence of individual metabolites was highly variable, and the concentration of each metabolite varied considerably between samples. The prevalence and concentration of most metabolites were higher in grain elevators compared to compound feed mills. Differences between seasons and climatic zones were inconclusive. All samples contained multiple mycotoxins, indicating a highly complex pattern of possible inhalational exposure. A mean exposure of 20 ng/m3 of fungal metabolites was estimated, whereas a worst case scenario estimated as much as 10 ?g/m3. Although many of these compounds may be linked to toxicological and immunological effects through experimental or epidemiological studies, it still remains to be determined whether the detected concentrations implicate adverse health outcomes when inhaled.

Species diversity and cytotoxic potency of airborne sterigmatocystin-producing Aspergilli from the section Versicolores

“…These concentrations are in accordance with data obtained for STC levels in dust from cereal storages in Belgium (Median 1.3 μg/g) (Tangni and Pussemier, 2007). Although Straumfors et al (2015) reported STC in 56% of dust samples taken from grain elevators and compound feed mills in Norway, the levels of STC were 10 to 100-fold lower than in our study. This may be due to colder environmental conditions in the Scandinavian region, which are not favourable for STC production in grain.…”

“…Although mycotoxin inhalatory toxicity and health effects in humans are under debate, studies have shown that mycotoxin inhalation may be at least 10 times more toxic than oral intake (Creasia et al, 1987(Creasia et al, , 1990. Taking into account the results presented in our study together with data on exposure of workers to flour dust (Zuskin et al, 1998) and recently reported possible health risks of various mycotoxin exposure in grain dust from Norwegian grain elevators and compound feed mills (Straumfors et al, 2015), we should focus on the possible health risks of inhalatory exposure to STC in occupational environments. Zuskin et al (1998) showed that in the flour processing area of a Croatian confectionary industry, the mean total flour dust was 12.3 mg/m 3 .…”

“…If we take the maximum concentration of STC (2.35 μg/g) detected in grain mill dust and multiply it by the mean total flour dust (12.3 mg/m 3 ), the level of STC amounts to 0.03 μg/m 3 . Adults breathe around 30 L/min during moderate physical activity and inhale 14 m 3 of air during an 8 h shift with moderate activity (Straumfors et al, 2015). Thus, the daily inhaled STC would be 0.42 μg.…”

Cross-shift study of exposure–response relationships between bioaerosol exposure and respiratory effects in the Norwegian grain and animal feed production industry

“…Some candidate effect inducers may be a large number of microbial metabolites previously detected in grain dust. 35 It is also likely that some additives of animal feed could have effects.…”

Strategies for estimating human exposure to mycotoxins via food

“…Food monitoring studies investigate the prevalence and concentration of contaminants, including mycotoxins, in single food ingredients or foods (Lopez et al, 2016b;Schwartzbord and Brown, 2015;Straumfors et al, 2015). This increases the chance of detecting the mycotoxins under investigation.…”