Evaluation of culture media for detection of salmonellae in composted biosolids

Hu, C. J.; Gibbs, R.A.; Ho, G.

doi:10.1016/s0043-1354(97)00097-3

Cited by 3 publications

(1 citation statement)

References 17 publications

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“…As the most prevalent group of pathogenic microorganisms in sludge is enteric pathogens (Hay 1996), most of the studies evaluating hygienization of composting of sludge or waste were restricted (i) to the faecal indicators, i.e. faecal streptococci, faecal coliforms or Escherichia coli (Soares et al 1995;Vuorinen and Saharinen 1997;Sesay et al 1998;Tiquia and Tam 2000;Turner 2002), (ii) to Salmonella, which was used as a representative pathogen for modelling die off of enteric pathogenic micro-organisms (Hu et al 1997;Tiquia et al 1998;Sidhu et al 2001), or (iii) to both faecal indicators and Salmonella (Pereira-Neto et al 1986;Droffner and Brinton 1995). Only a few more general studies have reported, besides the behaviour of faecal indicators and Salmonella, the survival of other types of micro-organisms such as Yersinia enterocolitica, toxigenic E. coli, Shigella, staphylococci, sulfite-reducing anaerobe spores or nematode eggs (Goldstein et al 1989;Deportes et al 1998;Gantzer et al 2001;Hassen et al 2001).…”

Section: Introductionmentioning

confidence: 99%

Decrease of enteric micro-organisms from rural sewage sludge during their composting in straw mixture

Pourcher¹,

Morand

Picard-Bonnaud³

et al. 2005

J Appl Microbiol

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A . -M . P O U R C H E R , P . M O R A N D , F . P I C A R D -B O N N A U D , S . B I L L A U D E L , S . M O N P O E H O , M . F E D E R I G H I , V . F E R R É A N D G . M O G U E D E T . 2005.Aims: To study the decrease of enteric micro-organisms including viable nematode eggs, enteroviruses, faecal indicators (Escherichia coli and enterococci) and pathogenic bacteria (Listeria monocytogenes, Salmonella sp. and Clostridium perfringens) of a rural sewage sludge when it is composted for 7 months in mixture with straw. Methods and Results: Numbers of the test organisms and the physico-chemical parameters were measured on a monthly basis on the mixture, on the compost after being turned, and on the pile in three positions representing the part by which air is incoming, the bottom of the pile and the part through which air is outgoing. The lowest temperature in the pile was observed at the bottom, where it did not exceed 50°C against 66°C in the two other areas. There were no significant differences between the three areas in terms of micro-organism survival. Infectious enteroviruses were inactivated rapidly and were not found after the first turning whereas some genomes were detected until after the third turning. Escherichia coli and enterococci presented a similar survival rate and their number decreased by 4 log 10 whereas Salmonella decayed at a greater rate than L. monocytogenes. The numbers of C. perfringens decreased gradually to reach a final concentration in the mature compost of about 10 2 CFU g )1 dry matter (d.m.), which was similar to that of the faecal indicators. Conclusions: The hygienic effect of sludge composting in mixture with straw results in a significant reduction of enteric micro-organisms, the concentration of the faecal indicators in the final product being <64 most probable number g )1 d.m. The concentrations of Salmonella, enteroviruses and viable nematode eggs in the final productwere not detectable which is in accordance with the French legislation. Significance and Impact of the Study: The results which pointed out the different behaviour of the test microorganisms reflect the difficulty to propose a relevant indicator of hygienization. Otherwise, they show that composting is an efficient means for hygienization of sludge of rural wastewater treatment, where the straw is available close to their place of production.

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