The effect of storage on allergen and microbial agent levels in frozen house dust

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B Fahlbusch1, A Koch, J Douwes

  • 1Friedrich-Schiller-University of Jena, Institute of Immunology, Jena, Germany.

Allergy
|March 8, 2003
PubMed
Abstract

Insights

Storing house dust samples at -20°C for up to 10 months does not affect mite allergens, endotoxin, or beta-glucan. However, cat allergen (Fel d 1) levels may decrease over time, requiring further investigation for accurate exposure assessments.

Area of Science:

  • Environmental science
  • Allergen research
  • Microbiology

Background:

  • House dust samples are crucial for exposure studies but their storage conditions are not well understood.
  • The impact of storage duration on biocontaminant levels in dust samples remains largely uninvestigated.
  • Understanding storage effects is vital for reliable exposure assessment in indoor environments.

Purpose of the Study:

  • To analyze the association between storage duration of house dust samples at -20°C and the levels of specific biocontaminants.
  • To investigate the stability of mite allergens (Der p 1, Der f 1), cat allergen (Fel d 1), endotoxin, and beta(1-->3)-glucan under frozen storage.
  • To determine if storage duration affects the accuracy of allergen and microbial component measurements in dust samples.

Main Methods:

  • Collected 1236 house dust samples from 655 homes as part of the INdoor factors and Genetics on Asthma (INGA) study.
  • Measured concentrations of Der p 1, Der f 1, Fel d 1, and beta(1-->3)-glucan using enzyme immunoassays.
  • Quantified endotoxin using the Limulus amoebocyte lysate (LAL) test, expressing all results per gram of dust.

Main Results:

  • No statistically significant changes were observed in Der p 1, Der f 1, endotoxin, or beta(1-->3)-glucan levels after storage for up to 298 days at -20°C.
  • A significant decline in cat allergen (Fel d 1) concentrations was observed with increasing storage duration.
  • Storage duration categories (<= 60 d, 61-90 d, 91-120 d, > 120 d) were compared after adjusting for city and season.

Conclusions:

  • Frozen storage of house dust samples at -20°C for up to 10 months is suitable for preserving mite allergen, endotoxin, and beta(1-->3)-glucan levels.
  • The observed decrease in Fel d 1 suggests potential degradation during frozen storage, warranting further research.
  • Accurate assessment of cat allergen exposure may require re-evaluation of sample storage protocols and measurement techniques.

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