cen:proj:35671

Sludge, treated biowaste and soil - Methods for the validation of biotechnological, thermal and chemical processes for the treatment of animal by-products, sewage sludge and biowastes in order to determine the hygienic safety of the resulting fertilizers or comparable products

Scope

This document is developed in the framework of the project "Horizontal". It is the result of a desk study "Prevention-Process control and process Validation". After discussion with all parties concerned in CEN the standard has been developed further as a modular horizontal method. The capability of a process to inactivate pathogens causing raw material dependant risks cannot be judged on by analysis of presence or absence of indicators (Bacterial, viral, fungal or parasitic) in the final product. Absence of all or one of the mentioned pathogens or indicators in the final product may be caused by several reasons. They may not be present in the raw material, they may be present in the raw material but in a low count (less than 5 log), the existing methods for reisolation of the target organism are insufficient in the investigated matrix due to ineffective enrichment procedures (e.g. bacteria) or the quantitative isolation of the indicator is technically not possible due to effects of the complicated matrix (e.g. viruses).
Even if the possibility of validating a process by input-output analysis of a certain indicator is generally given and will be covered in clause X input- output analysis under practical conditions is depending on the microbiological properties of the input materials processed and therefore limited in feasibility under practical conditions. Therefore other strategies must be followed in such a case, e.g. process validation with one or more representative test-organism. Either if the thermophilic process itself or if a thermal treatment shall provide an inactivation of pathogens belonging to the indicated level of thermo- and
chemoresistance, representative test-organisms must be exposed in a similar matrix as treated in a suitable test containment system (test-body) in a defined validation experiment.
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