VACUUM VERSUS BRUSH CLEANING IN FARM FEED MILLS

The design and layout of farm feed mills does not acknowledge the need for routine cleaning. Cleaning with brushes caused exposure to inspirable dust concentrations of between 22 and 138 mg/m3. Four out of six exposures were in excess of legally defined limits. Cleaning with vacuum equipment caused exposure to inspirable dust concentrations of between 0.3 and 32 mg/m3. Vacuum equipment was more effective at removing dust, created a better working environment and was more able to clean awkward areas than cleaning with brushes. Problems with vacuum equipment included the weight and blocking of hoses, inappropriate nozzle designs, and disposal of collected dust. Settled dust concentrations in the mill areas were highly variable and were not significantly reduced by cleaning the mill area. Vacuum equipment is available on approximately 20% of farms with registered feed mills, but are used infrequently. The potential for increasing vacuum use is very high. There are almost 25 000 fixed and mobile milling and mixing plants in the UK. The need to improve hygiene in the mill area should be promoted within the agricultural industry.