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The role of indigenous microorganisms in suppression of salmonella regrowth in composted biosolids
Journal article   Peer reviewed

The role of indigenous microorganisms in suppression of salmonella regrowth in composted biosolids

J. Sidhu, R.A. Gibbs, G.E. Ho and I. Unkovich
Water Research, Vol.35(4), pp.913-920
2001
DOI: https://doi.org/10.1016/S0043-1354(00)00352-3
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Abstract

Composting is commonly used as an effective means of stabilizing wastewater biosolids and reducing pathogens to very low concentrations. However, it has been shown that under certain conditions Salmonella can regrow in previously composted biosolids. Growth of seeded Salmonella typhimurium in composted biosolids ranging from two weeks to two years maturity was monitored. Results from sterile and non-sterile composted biosolids were compared. Seeded S. typhimurium colonized rapidly in sterilized biosolids reaching a maximum population density of more than 108g-1. Growth of seeded S. typhimurium was suppressed in non-sterilized compost with a maximum population density of less than 103g-1. There was a significant decline in the growth rate of seeded Salmonella in sterilized compost when the compost was stored, suggesting that bio-available nutrients declined with storage. However, in non-sterilized compost this was not the case. This suggests that the indigenous microflora play a significant role in suppression of Salmonella regrowth in composted biosolids. There was a strong negative correlation (-0.85) between the Salmonella inactivation rate and the maturity of compost in non-sterilized compost. The Salmonella inactivation rate was seven times higher in biosolids composting for two weeks as compared to compost stored for two years. This suggests that the antagonistic effect of indigenous microorganisms towards Salmonella declined with compost storage. It was concluded that all composted biosolids had a Salmonella regrowth potential. However, the indigenous microflora significantly reduced this regrowth potential. Long-term storage of compost is not recommended as this may increase the pathogen regrowth potential.

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Source: InCites

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130 Times Cited - Web of Science

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Collaboration types
Industry collaboration
Domestic collaboration
Citation topics
3 Agriculture, Environment & Ecology
3.45 Soil Science
3.45.1441 Composting Innovations
Web Of Science research areas
Engineering, Environmental
Environmental Sciences
Water Resources
ESI research areas
Environment/Ecology
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