Mite control with low temperature washing. I. Elimination of living mites on carpet pieces

BACKGROUND: Washing of delicate textiles at low temperature combined with mite control is one of the important aims for domestic mite prevention. OBJECTIVES: Estimation or assessment of mite numbers without and after the application of detergents or detergents with mite control additive. Trials at low temperature, detergents and washing as usual at household conditions (programme of a household washing machine). METHODS: The domestic mite Dermatophagoides farinae can be cultured on carpet samples under favourable conditions, and the breeding success monitored in terms of population and distribution using the free mite mobility test. The mite containing carpets were cut into pieces in order to investigate the effects of washing at low temperature with different commercial detergents with and without an additive for mite control. The heat escape method was used to assess the number of mites remaining on the carpet pieces. RESULTS: The estimation of the mite populations on different carpet pieces before and after washing showed that between 40 and 60% of the mites were able to resist washing, rinsing, spinning and drying. The allergen containing dust, however, was flushed out. In contrast, complete mite control was achieved by the application of the same detergents together with an additive. CONCLUSION: Mite control by low temperature washing is possible with a mite control additive provided that a concentration of benzyl benzoate of about 0.03% is achieved in the washing suds.