What is Non viable “Burkard” Sampling


Let us begin by defining "Non-Viable" and "Viable". Non-viable refers to techniques that identify fungal spores or conidiophores without any attempt to culture the spores. It does not infer that the spores are not capable of germination or growth. Viable techniques are an attempt to recover either fungal spores or bacterial cells in the environment from which they were collected. For the purpose of this discussion, non-viable would refer to the microscopic examination of spore trap, tape, bulk or swab samples. Viable would include the collection and growth of fungal spores or bacterial cells on agar plates or dilution plate culturing of fungal or bacterial cells from swab, bulk or dust samples.

Burkard spore trap sampling is a non-culture based tool that provides a snapshot of the kinds and levels of total (viable and non-viable) airborne fungal (mold) spores present in the indoor environment. Direct microscopy is used to analyze Burkard samples, providing both a qualitative and quantitative assessment of spores in the air in a short timeframe. Air sampling is used to determine whether the mixture of airborne fungi in a building is normal and typical or indicative of moisture problems. Air sampling is also an important tool for conducting exposure assessments. Burkard sampling provides a quicker turnaround time than culture-based analysis, when rapid communication of results is essential. Often investigators use non-culturable air sampling as post-remediation clearance testing to evaluate effectiveness.

Burkard slide shows Curvularia Spore

 

Burkard Sampler

This method provides report on both raw spore counts for individual spore types and total concentration expressed as particles per cubic meter (particles/m3). The proportions of each spore type are also calculated and important groupings of fungal types are summarized to facilitate interpretation of results. We can also include qualitative data on pollen and skin scales for each sample.

Burkard spore trap sampling is a device designed for the rapid collection and analysis of a wide range or airborne aerosols. These include fungal spores, pollen, skin cell fragments, fibers and inorganic particulates. Air enters the cassette, the particles become impacted on the sampling substrate, and the air leaves through the exit orifice. The airflow and patented cassette housing is designed in such a way that the particles are distributed and deposited equally on a special glass slide contained in the cassette housing.

Advantages

  • Useful for initial site testing, especially if fungal growth is not visible
  • Provide rapid delivery of total spore counts and types in air samples
  • Easy to use and handle in the field
  • Provides a convenient analysis to identify and enumerate spores and structures without the additional time required to culture fungal samples

Disadvantages

  • Fungi cannot be fully speciated with this method. For example, Aspergillus sp and Penicillium sp are normally reported together due to the similarities in spore morphology.
  • Spore viability cannot be assessed, as it is not possible to differentiate between viable and non viable spores.