Testing of processes in growing media production on sanitation effectiveness with Bacillus globigii as a test organism

Raw materials for producing growing media for horticultural purposes must be free of contaminants like pests.
Some raw materials need to be treated to kill pests that could be present.
The effectiveness of the sanitation (hygienization) process depends on pest-related aspects as the type of organism and infestation level, on the one hand, and the treatment chosen, on the other.
There is a need for a test to assess the effectiveness of such a process in a simple way with minimal sanitary and phytosanitary risks.
For this reason, a test was developed using Bacillus globigii as an indicator organism.
Spores are counted before and after application of three different treatments that are used by the growing media industry: steaming, irradiation and friction heat.
The materials tested were peat, wood fiber and sphagnum.
The results of experiments using Bacillus globigii as a test organism were compared with existing tests using tomato mosaic virus and tomato seeds. Bacillus globigii appeared to function well as a test organism.
The results were related to the existing tests.
The levels of decreased contamination (biological log reduction) could be estimated easily with a high distinction depending on the treatment.
This makes the test valuable for certification purposes.

III International Symposium on Growing Media, Composting and Substrate Analysis

G. Wever, J.B.G.M. Verhagen, T. Schilling

ToMV, steam sterilisation, gamma sterilisation, frictional heat, peat, wood fiber, sphagnum moss, RHP

https://doi.org/10.17660/ActaHortic.2021.1305.19