Hydrothermal treatment for inactivating some hygienic microbial indicators from food waste–amended animal feed

Abstract

To achieve the hygienic safety of food waste used as animal feed, a hydrothermal treatment process of 60-110 C for 10-60 min was applied on the separated food waste from a university canteen. Based on the microbial analysis of raw waste, the inactivation of hygienic indicators of Staphylococcus aureus (SA), total coliform (TC), total aerobic plate counts (TPC), and molds and yeast (MY) were analyzed during the hydrothermal process. Results showed that indicators' concentrations were substantially reduced after hydrothermal treatment, with a greater reduction observed when the waste was treated with a higher temperature and pressure and a longer ramping time. The 110 C hydrothermal treatment for 60 min was sufficient to disinfect food waste as animal feed from the viewpoint of hygienic safety. Results obtained so far indicate that hydrothermal treatment can significantly decrease microbial indicators' concentrations but does not lead to complete sterilization, because MY survived even after 60 min treatment at 110 C. The information from the present study will contribute to the microbial risk control of food waste-amended animal feed, to cope with legislation on food or feed safety.Implications: Reduction of microbial indicators at ramping time and holding time during the hydrothermal process showed that hydrothermal treatment is an effective method to achieve hygienic feed from food waste to a certain extent, but the conditions researched in this study were not enough for the complete sterilization of food waste, because of the different heat resistance of bacteria and spores.

A study of the impact of moist-heat and dry-heat treatment processes on hazardous trace elements migration in food waste

“…And consequently, studies on dry-heat treatment have mainly focused on the treatment of sludge, fly ash, and other materials Ohm et al, 2009;Ramaroson et al, 2008;Zhang et al, 2011a), whereas studies on moist-heat treatment have primarily focused on material synthesis and carbonization treatment (Gao et al, 2012;Lin et al, 2010;Reza et al, 2013;Xiang et al, 2002;Xu and Lancaster, 2008;Yang et al, 2013). But only a few studies have been conducted on the application of these two heat treatments on food waste Jin et al, 2012;Kelley and Walker, 2000), and in particular, studies comparing the effect of trace elements removal on these two heating treatment processes are rare.…”

“…Therefore, the resource utilization of food waste, such as anaerobic biogas production (Cekmecelioglu and Uncu, 2013;Chen et al, 2014;Forster-Carneiro et al, 2008;Tawfik and El-Qelish, 2012), feedstuff production (Kwak and Kang, 2006;Jin et al, 2012;Westendorf et al, 1998;Yang et al, 2006), and composting (Hwang et al, 2002;Seng et al, 2013;Kim et al, 2008), draws particular attention of researchers as well as administrators. For instance, from 2010 to 2014, the Chinese government launched a program for the resource utilization and safe treatment of food waste in 67 pilot cities, with the total treatment capacity as 17,770 tons/day.…”

A safety analysis of food waste-derived animal feeds from three typical conversion techniques in China

“…Afterwards, outbreaks of disease have been associated with this traditional recycling method by epidemiological investigations (Cole et al, 2000). Many studies recognized that food wastes readily deteriorate and pollute the surroundings and transfer diseases to animals and humans (Lee et al, 2007;Jin et al, 2012;Papargyropoulou et al, 2014;Sapkota et al, 2007). Thus, this traditional technique is now gradually being abandoned because of the incomplete disinfection and the high potential of exogenous contamination during application (Elferink et al, 2008;Westendorf, 2000;Jo, 2001) and is not included in our research.…”

Pengaruh Penambahan Zeolit pada Proses Pelletizing Limbah Penetasan Terhadap Kandungan Coliform dan Salmonella Produk Pellet

“…Pada penelitian ini, suhu yang digunakan saat kondisioning pada kisaran 80⁰C atau suhu yang umum digunakan untuk membunuh bakteri pathogen, sehingga ketika kisaran Coliform dalam produk pellet pada jumlah 10 5 -10 7 cfu/g dan Salmonella tidak terdeteksi, menunjukkan kemampuan zeolit dalam bersinergi dengan proses pemanasan dan pelletizing dalam mengendalikan populasi Coliform dan Salmonella. Pengaruh proses pemanasan pada penelitian ini, sejalan dengan Jin et al (2012), bahwa proses hydrothermal sampai 110⁰C, efektif untuk meningkatkan hygienitas pakan dari limbah pangan dengan menekan perkembangan mikrobia, namun tidak sampai menghilangkan sama sekali kandungannya. Suwito (2010), mencatat bahwa 6-7% bahan pakan beresiko tercemar Coliform dan Salmonella.…”