Forensic Mycology How do Hygienist Add Value? Dr Heike Neumeister-Kemp Mariam Begum Sam Athanasios

Transcription

1 Forensic Mycology How do Hygienist Add Value? Dr Heike Neumeister-Kemp Mariam Begum Sam Athanasios

2 Case study Tenant claimed lack of maintenance by landlord of a commercial building resulting in defects causing mould proliferation Building mould proliferation claimed to be causing extensive mould proliferation/damage to stock, and repository symptoms in staff handling the stock Inspection and sampling identified inconsistent and disparate mould levels on stock items Forensic analysis of samples different species of mould in the building to that on stock Concluded that source of observed mould was not in the building

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4 Methods Used three different sampling techniques Each technique targeted at producing answer to slightly different question Viable airborne sampling what is the level and species of live mould in the air? Non-Viable airborne sampling what is the total level mould in the air, and the relative quantities of each genera in the genera spectrum? Non-viable surface sampling what is the total level mould on stock items, and the relative quantities of each genera in the genera spectrum?

5 Table 1: Viable Airborne Fungal Concentrations (CFU/m3) Location CFU/m3 Rating Above / Below OA Outdoor Air Reference 618 High NA 530 High NA Shoes section middle 106 Very Low Below Shoes section front 230 Moderate Below Shoes section end wall 194 Moderate Below Shop front aisle 106 Very Low Below Shop end LH 141 Low Below Cashier 247 Moderate Below Shop middle aisle BDL BDL Below Shop end aisle RH 71 Very Low Below Indoor Average 137 Low Below Outdoor Average 574 High -

6 Table 1: Viable Airborne Fungal Concentrations (CFU/m3) CFU/m 3 BDL 18 <107 <142 <177 <354 <707 <2827 <5652 >7067 Rating BDL Single Colon y Low to Very Low Low Moderat e Moderat e High Very High Extremel y High TNTC

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8 Table 2: Legend Viable Airborne Fungal Genera Mixture

9 Table 2: Legend Viable Airborne Fungal Genera Mixture

10 Results The various sampling techniques employed showed that there were two main groups of mould genera/species present One genera/species was found predominantly of the stock items The second genera/species group was found predominately in the building environment The levels of genera/species group found on the stock items was generally much higher than the level of the genera/species group found in the building environment Not all stock items were equally affected, with some heavily affected, and others almost clear of mould

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13 Table 3: Viable Surface Fungal Concentrations (CFU/Plate) Location CFU/Plate Rating Inside shoe contamination 25 Moderate Inside shoe clean BDL BDL HVAC vent 2 Very Low Rating BDL Very Low Low Moderate High Very High Extremely High TNTC CFU/Plate < >594 CFU/cm2 < >25.0

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15 Figure 2: Viable Surface Fungal Concentrations (CFU/Plate)

16 Symbol CFU/Plate <1 <6 <18 <30 <60 >150 Rating BDL Several Establishe Moderate High Dominant Colonie d Concentration Concentration Genera s Genera s s

17 Table 5: Non-Viable Bio-Tape Surface Fungal Spore Concentrations (spores/cm2) Conce ntratio ns (spore s/cm2 ) Asper gillus/ Penicil lium sp. Clados poriu m sp. Altern aria sp. Gen Dirt & Debris (L, M, H, VH) RATI NGS (BDL, L, N, E, C, EC) Location Inside shoe contamination Low EC HVAC vent Very High EC Inside shoe contamination Low EC

18 Total (Viable + Non-viable) Fungal Hygiene Guide for Indoor Surfaces Hygiene Rating Below Detectable Limits (BDL) Lowb (L) Normal (N) Elevatedc (E) Contaminatedd (C) Extreme Contaminatione (EC) Totala Surface Fungal Spora Concentration <1 spore/m3 < 50 spores/cm2 50 to 500 spores/cm2 500 to 1000 spores/cm2 + prevailing species > 1000 spores/cm2 + dominant species + Propagules > 5000 spores/cm2 + dominant species + Propagules + confluent spores

19 Figure 3: Non-Viable Surface Fungal Spores Concentrations (spores/cm2)

20 Table 6: Indoor Air Quality Results Location CO2 (ppm) Air Temp ( C) RH (%) Outdoor Air Shoes end Shoes middle Cashier Shop front Shoes front Ladies shoes

21 Results The various sampling techniques employed showed that there were two main groups of mould genera/species present One genera/species was found predominantly of the stock items The second genera/species group was found predominately in the building environment The levels of genera/species group found on the stock items was generally much higher than the level of the genera/species group found in the building environment Not all stock items were equally affected, with some heavily affected, and others almost clear of mould

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23 Summary A building defects dispute was claimed to have resulted in mould proliferation and consequent contamination, reportedly affecting staff and stock Inspection, sampling and analysis were conducted to inform a forensic mycology analysis Two distinct genera/species groups were identified, with one group exhibiting much higher levels than the other A forensic mycology analysis concluded that the source of mould proliferation was not the building environment It was found that contaminated stock was brought into the building the building was not the source of mould proliferation

24 Conclusion A carefully targeted sampling strategy, and forensic mycology analysis can be a very powerful and significant value-add tool A robust and structured approach can produce an accurate evidencebased result, even though the result may have appeared completely counter-intuitive at the outset The accurate identification of the source of mould, ensured steps for the protection of staff and other stock Forensic mycology analysis likely saved hundred's of thousands of dollars, in litigation costs, and presented a very significant value-add.