Inactivation of Salmonella during dry co-digestion of food waste and pig manure

Jiang, Yan and Dennehy, Conor and Lawlor, Peadar G. and Hu, Zhenhu and Yang, Qingfeng and McCarthy, Gemma and Tan, Shiau Pin and Zhan, Xinmin and Gardiner, Gillian E. (2018) Inactivation of Salmonella during dry co-digestion of food waste and pig manure. Waste Management, 82. pp. 231-240. ISSN 0956-053X

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Extremely high volatile fatty acids (VFAs) and ammonia concentrations can accumulate during dry co-digestion of organic wastes, which may inactivate pathogenic microorganisms. In this study, inactivation of Salmonella during dry co-digestion of pig manure (PM) and food waste (FW), which are both reservoirs of zoonotic pathogens, was examined. The effects of pH, VFAs, ammonia and their interactions were assessed on three inoculated Salmonella serotypes. The results show that dry co-digestion significantly decreased the Salmonella inactivation time from several months (in wet digestion) to as short as 6–7 days. A modified Weibull distribution was proposed to simulate Salmonella reduction and to calculate or predict the minimum inhibitory concentrations (MIC) of VFAs and ammonia. Statistical analysis showed that all the factors (pH, VFA type, VFA/ammonia concentration and Salmonella serotype) significantly impacted Salmonella inactivation (P < 0.01). The inhibitory effect sequence was pH > VFA concentration > VFA type > Salmonella serotype in VFA MIC tests, and ammonia concentration > pH > Salmonella serotype in ammonia MIC tests. The toxicity of VFAs was much greater than that of ammonia, and an antagonistic effect was found between VFAs and ammonia on Salmonella inactivation. Apart from the toxicity of free VFAs and free ammonia, the inhibitory effects of pH alone, ionized VFAs and ammonium were also observed.

Item Type: Article
Additional Information: Funding Information: This work was funded by the Green Farm project supported by a Science Foundation Ireland Investigator Project Award (Ref: 12/IP/1519 ). Xinmin is also grateful for the support of the Natural Science Foundation of China (Ref: 51728801 ). We would also like to thank Dr. Kavita Walia for her help in serotyping of Salmonella using O- and H-group antigens method. Publisher Copyright: © 2018 Elsevier Ltd
Uncontrolled Keywords: /dk/atira/pure/subjectarea/asjc/2300/2311
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Depositing User: Admin SSL
Date Deposited: 19 Oct 2022 23:06
Last Modified: 20 Jul 2023 16:05

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