Efficacy of Structural Pasteurization

Efficacy of Structural Pasteurization for Reduction of Viable Bacterial Levels in Indoor Environments

Sean P. Abbott(1), Larry Chase(2) and M. Chance Villines(1)

(1)Natural Link Mold Lab, Inc., 4900 Mill Street, Suite 3, Reno, Nevada 89502, USA
(2)Precision Environmental, 180 Cañada Larga Road, Ventura, California 93001, USA

SUMMARY
This study examines the efficacy of high temperature pasteurization of buildings for reducing levels of viable bacteria in indoor environments employing both laboratory and field data. Laboratory heat chamber testing using four species of environmental bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus) at a range of temperatures and durations was performed to determine efficacy of thermal application. Bacteria exposed to high temperature/short duration (60-75°C for 0.25-4 hr) demonstrated that thermal death occurs rapidly at temperatures of 60°C or higher. When exposed to low temperature/long duration (45-50°C for 4-120 hr), time required to reach the thermal death point was significantly extended. Laboratory-prepared samples inoculated with E. coli were also subjected to the thermal sanitization process in field situations to confirm effectiveness at temperatures and durations routinely used for sewage remediation projects. Results demonstrated mortality of E. coli at 60°C for 2 hours.

IMPLICATIONS
Structural pasteurization employs engineer-controlled convective dry heat to sanitize building materials in situ, and is typically used in conjunction with structural drying and traditional microbial remediation processes. Building pasteurization allows for sanitization of entire structures and can provide significant hygiene benefits by reducing overall levels of microorganisms in indoor environments.

CONCLUSIONS
This study demonstrates that structural pasteurization can be an effective process to reduce environmental bacteria that are known to accompany damp structures.  Included as a part of the restorative drying process, structural pasteurization can be an effective sanitizer and provides improved levels of cleanliness.

PUBLICATION CITATION
Abbott, S.P., L. Chase and M. C. Villines. 2011.  Efficacy of structural pasteurization for reduction of viable bacterial levels in indoor environments.  Indoor Air (in press, accepted Jan 25, 2011).