Inactivation of Salmonella Senftenberg strain W 775 during composting of biowastes and garden wastes.
OBJECTIVE
Determination of the minimum requirements (time-temperature relationship and moisture content) that are needed for a sufficient eradication of an indicator organism.


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 degrees 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.


CONCLUSIONS
To give a better view on the parameters of importance for the eradication of W 775 during composting.
Ceustermans
A
A
Laboratory of Phytopathology and Plant Protection, Katholieke Universiteit Leuven, Leuven, Belgium.
De Clercq
D
D
Aertsen
A
A
Michiels
C
C
Geeraerd
A
A
Van Impe
J
J
Coosemans
J
J
Ryckeboer
J
J
D001673:Biodegradation, Environmental; D015169:Colony Count, Microbial; D008460:Meat / Q000382:microbiology; D012037:Refuse Disposal / Q000379:methods*; D019779:Salmonella enterica / Q000145:classification / Q000254:growth & development* / Q000302:isolation & purification; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000032:analysis
D014867:Water