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Inactivation of Salmonella Senftenberg strain W 775 during composting of biowastes and garden wastes
Author(s) -
Ceustermans A.,
De Clercq D.,
Aertsen A.,
Michiels C.,
Coosemans J.,
Ryckeboer J.
Publication year - 2007
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2006.03224.x
Subject(s) - salmonella , strain (injury) , microbiology and biotechnology , food science , biology , bacteria , genetics , anatomy
Aims: Determination of the minimum requirements (time–temperature relationship and moisture content) that are needed for a sufficient eradication of an indicator organism. Methods and Results: To determine the hygienic safety of composting processes, the indicator organism Salmonella enterica ssp. enterica serotype Senftenberg strain W 775 (further abbreviated as W 775) was artificially inoculated on a meat carrier and monitored subsequently. Different types of composting processes, e.g. composting in enclosed facilities, in open‐air and in‐vessel composting, were investigated. The waste feedstocks used in this work were either biowastes (i.e. vegetable, fruit and garden wastes; also called source‐separated household wastes) or pure garden wastes. Beside these large‐scale trials, we also conducted some lab experiments in order to determine the impact of temperature, moisture content and the presence of an indigenous microflora on the eradication of W 775. We found the temperature to be the most important parameter to eradicate W 775 from compost. When the temperature of the compost heap is 60°C and the moisture content varies between 60–65%, W 775 (10 8 CFU g −1 ) will be inactivated within 10 h of composting. The moisture content is, beside temperature, a second parameter that influences the survival of W 775. When the water content of the composting materials or meat carriers is reduced, a higher survival rate of W 775 was observed (survival rate increases 0·5 log 10 unit when there is a reduction of 5% in moisture content). In addition, other parameters (such as microbial antagonism, toxic compounds, etc.) have an influence on the survival of W 775 as well. Conclusions: Our study demonstrates that all types of composting processes tested in this work were sufficient to eradicate W 775 providing that they are well managed in terms of temperature and moisture content. Significance and Impact of the Study: To give a better view on the parameters of importance for the eradication of W 775 during composting.