No abstract

Modern metalworking fluids (MWFs) provide the breeding ground for microorganisms that could enter the ambient environment via aerosolization. This manuscript describes the occurrence, type, concentration and size distribution of bacteria and fungi in an MWF environment by sampling aerosols and MWF sumps. In this study, computer numerical control (CNC) thread-cutting and grinding processes at a socket-manufacturing plant were investigated. Cladosporium and Aspergillus were the dominant fungal isolates in this study. Peak fungal concentrations (797 CFU/m 3 ) were observed during threadcutting processes, and the most prevalent fungi were in the size range of 2.1-3.3 lm. Moreover, Exiguobacterium spp., Micrococcus spp., and Staphylococcus capitis were the dominant bacterial isolates identified. The most prevalent bacteria were in 4.7-7.0 lm size range. This study indicates that the type of machine tools was not associated with MWF sump microbial concentrations. The total bacterial and fungal contamination in MWF sump samples reached levels of 10 5 CFU/ml. Pseudomonas spp. was the only bacterium identified in the MWF sumps, and Aspergillus, Penicillium, and yeast were the predominate fungi identified.