Validation of Colilert-18 Method for Detection of Escherichia Coli in Compost

Ladislava Matějů¹, Bostikova Z.², Zimova M.¹, Brewin B.³, and Zufanek J.⁴

1. National Institute of Public Health, Šrobárova 48, Prague, Czech Republic

2. University of Chemistry and Technology, Prague, Czech Republic

3. IDEXX Technologies UK, Newmarket Business Park, Studlands Park Avenue, Newmarket, Suffolk, United Kingdom

4. Cymedica CZ,a.s., Pod Nádražím 308, Hořovice, Czech Republic

Abstract: European, as well as Czech legislation requires a microbiological quality control of treated biowaste, such as compost. Escherichia coli represents one of indicator organisms which is monitored. In this study a comparison of two quantification methods for E. coli was performed. The first one was a currently used method in the Czech Republic, consisting of direct plating of diluted compost sample on a membrane faecal coliform (mFC) agar with subsequent E. coli confirmation. The second method was Colilert-18, which was evaluated by this study as a suitable alternative to mFC agar for the analysis of compost and similar matrices for the presence of E. coli and should be considered as an alternative method in the context of revised regulations.

Key words: Escherichia coli, compost, Colilert-18, sludge