Usefulness of using three different culture media for mold recovery in exposure assessment studies

Abstract

The choice of culture media when performing exposure assessment for mold quantification is difficult since no standard methods exist and, in many cases, there is no way to predict, before hand, the mold population present and thus, select the most appropriate media. The aim of this project was to compare the efficiency and usefulness of 3 widely used culture media during the recovery of molds in sawmills. Andersen microbial samplers (AMS) and all-glass impingers-30 (AGI-30) were used to sample 51 work sites within 17 sawmills. Rose Bengal Agar (RBA), Czapek Solution Agar (CZA) and Sabouraud Dextrose Agar (SDA) were used directly in AMS and to plate AGI-liquid. The results show that there was no signification difference between the three culture media concerning the counts and the species recovery. However, SDA often lead to non usable counts. The variations obtained with the different culture media when AGI-30 were plated in triplicate was also not significantly different. However, only 19% of the species recovered at one site were present on all culture media. We believe the use of various media increases the chances of obtaining valid counts and an adequate species recovery.