[Effectiveness of environmental disinfection with formalin aerosol]

The effectiveness was tested of preventive disinfection of pig-fattening houses with formalin, applied as aerosol with the Swingfog SN 100 apparatus. The effectiveness of this treatment was evaluated according to the proportion of smears containing lactoso-positive micro-organisms, expressed as a percentage of the total number of smears, and according to the reduction of contamination with E. coli and St. aureus on wooden or aluminium carriers. The effectiveness was found to be good and the treatment is recommended as suitable for the preventive disinfection of stables. However, the following procedure should be strictly observed: Before disinfection the stables must be thoroughly mechanically cleansed, dried, and well closed to be air-tight. The air temperature in these premises should not be lower than 12 degrees C. Formalin (with a minimum content of 40% of formaldehyde) should be applied at a rate of at least 10 ml per 1 m3 of space and the agent should be diluted with water at 1 : 1 ratio prior to use. The aerosol should be produced by the Swingfog SN 100 generator, adjusted to apply about 40 1 of the solution per hour. The maximum space treated from one place should be limited to 500 m3. The exposure time should be at least 16 hours.