Mite control with low temperature washing-II. Elimination of living mites on clothing.
BACKGROUND: Allergens produced by mites are one of the principal causes of allergic disease. House dust mites can be found in significant numbers living in textile garments, and therefore development of optimal washing conditions for delicate textiles represents an important aim for domestic mite control. OBJECTIVES: Investigation of methods to eliminate house dust mites from clothing under low temperature washing conditions. METHODS: Domestic house dust mites Dermatophagoides farinae were cultured on garments under favourable conditions. The breeding success was monitored in terms of population and distribution using the free-mite Mobility Test. The mite containing garments were washed at low temperature with different commercial detergents in the presence or absence of a mite control additive containing 0.03% benzyl benzoate, and the numbers of mites surviving the washing process were assessed using the Heat Escape Method. RESULTS: The successful culture of mites in textile garments led to mite numbers of a total of at least 9000 to 10000 mites in 10 garments (Mobility Test). After washing in a domestic washing machine with detergents alone approximately 6000 remaining mites were detected in 10 garment halfs (Heat Escape Method). In contrast, mite control by the application of the same detergents together with an additive achieved a reduction to almost 50 mites. This is an additional reduction in mite numbers of 99.2%. CONCLUSIONS: It is possible to achieve mite control in delicate garments by washing at low temperature in the presence of a mite control additive providing a final concentration of 0.03% benzyl benzoate.