ERA

Download the full-sized PDF of Developing and Testing a Framework to Measure the Sanitation Efficacy on a Random Particle Level in Composting IndustryDownload the full-sized PDF

Analytics

Share

Permanent link (DOI): https://doi.org/10.7939/R3TH8BT9R

Download

Export to: EndNote  |  Zotero  |  Mendeley

Communities

This file is in the following communities:

Graduate Studies and Research, Faculty of

Collections

This file is in the following collections:

Theses and Dissertations

Developing and Testing a Framework to Measure the Sanitation Efficacy on a Random Particle Level in Composting Industry Open Access

Descriptions

Other title
Subject/Keyword
pathogen
temperature
composting
criteria
sanitation
Type of item
Thesis
Degree grantor
University of Alberta
Author or creator
Isobaev, Pulat
Supervisor and department
McCartney, Daryl (Civil and Environmental Engineering)
Examining committee member and department
Neumann, Norman (School of Public Health)
Felske, Christian (City of Edmonton)
Clark, Grant (Bioresource Engineering, McGill University)
Bouferguene, Ahmed (Campus St. John)
Yang, Liu (Civil and Environmental Engineering)
Buchanan, Ian (Civil and Environmental Engineering)
Department
Department of Civil and Environmental Engineering
Specialization
Environmental Engineering
Date accepted
2014-07-08T10:27:20Z
Graduation date
2014-11
Degree
Doctor of Philosophy
Degree level
Doctoral
Abstract
Both direct and indirect process validation regulations are being used to ensure the safety of compost products. The North American guidelines specify upper limits for certain pathogenic and indicator microbes, which are presumably achieved by exposing every particle of compost to temperatures ≥55°C for at least 3 consecutive days. Regardless of maintaining high temperatures, there may still be pathogenic microorganisms that survive composting. Hypothetically, this could be because: (1) temperature test methods may not account for spatial and temporal temperature variation in large composting piles, giving the false impression the temperature-contact time condition has been met; and/or (2) the existing temperature contact time criterion may be inadequate. A temperature probe was developed consisting of a temperature recording circuit and inoculum holder (i.e., cryovial) enclosed in a cylindrical case made of anodized aluminum. Two field trials suggested that this probe behaves like a random particle in compost. Both trials also showed that the aluminum case protects the probe’s circuitry and the cryovial from various physical and chemical stresses. The temperature probe was used to develop a temperature sampling framework for the indirect process validation. It suggested that in a covered aerated static pile the likelihood for a random compost particle to reach and maintain ≥55°C for at least 3 consecutive days varies between 76 – 93% and could increase to 98% after five pile turnings. Typical cool zones mostly remained at ≤45°C, resulting in questionable thermal inactivation responses for pathogenic microorganisms. A direct technology validation framework using the temperature probe was developed and proposed. Two experimental runs demonstrated that samples in which temperatures ≥55°C were maintained for at least 3 consecutive days were free of culturable Salmonella sp., Escherichia coli sp., and phi-S1 bacteriophage. However, a sample that remained in the cool zone throughout one experiment run still had culturable Salmonella in appreciable amounts thus reiterating the importance of cool zones in the sanitation process. Molecular analysis of the samples demonstrated that a gradual increase in compost temperature induced a potential viable but not culturable state in Salmonella and E. coli. It was concluded that the specified time-temperature conditions are likely adequate but more research is needed to study the behavior of VBNC pathogens in compost.
Language
English
DOI
doi:10.7939/R3TH8BT9R
Rights
Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.
Citation for previous publication

File Details

Date Uploaded
Date Modified
2015-01-08T08:02:05.381+00:00
Audit Status
Audits have not yet been run on this file.
Characterization
File format: pdf (PDF/A)
Mime type: application/pdf
File size: 7405585
Last modified: 2015:10:12 18:23:42-06:00
Filename: Isobaev_Pulat_201407_PhD.pdf
Original checksum: 9619ad6c2538094c8f822918fd2815e7
Activity of users you follow
User Activity Date