Estimation for bacterial safety of methane fermentation liquid from swine excrement slurry
2010
Sonoda, R., Miyazaki Univ. (Japan). Faculty of Agriculture | Akagi, I. | Asano, Y. | Yamamoto, A. | Saeki, Y.
Recently, the domestic animal excrement causes serious water pollution and the problem of bad smell because of the inappropriate managements. The methane fermentation that is one of the methods of processing the animal excrement is expected as technology of a biomass recycling system, and the fermentation liquid is expected as liquid fertilizer. It is important to secure the safety for agricultural products when using it as liquid fertilizer. Therefore, in this study, we performed the evaluation about the microbiological safety of the fermentation liquid. The swine excrement slurry and the fermentation liquid processed by the biogas plant at University of Miyazaki were used as the samples. We researched about coliform bacteria, detection by PCR with specific primer sets for pathogenic bacteria, Biolog indices based on utilization of carbon sources and detection of protozoa by the nested-PCR specific for Cryptosporidium. The coliform bacteria was not observed in fermentation liquid but observed in the excrement slurry by the coliform selective medium. In the PCR for food pathogenic bacteria, though E. coli was detected in the excrement slurry, pathogenic bacteria were not detected in any samples. Furthermore, the existence of pathogenic bacteria was not detected in the fermentation liquid by Biolog indices. In addition, Cryptosporidium was not confirmed in the fermentation liquid. These results indicate that fermentation liquid will be safe in terms of pathogenic bacteria for use as liquid fertilizer.
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