Growth potential of faecal bacteria in simulated psychrophilic/mesophilic zones during composting of organic waste

Abstract

Aim: This study investigated the growth potential of Salmonella serotype Typhimurium and faecal indicator organisms in compost materials and the correlation between bacterial growth potential and the physico‐chemical composition of the compost substrate and temperature. Methods and Results: Survival of Salm. Typhimurium, Enterococcus spp. and total coliforms at 14, 24 and 37°C was determined in material of different degrees of maturity collected from composting plants for household waste and manure. All three micro‐organisms showed the potential for growth in the material from active composts (Solvita index 4) but inactivation generally occurred over time in mature compost material (Solvita index 7–8). Conclusions: Salm. Typhimurium had the potential for growth in psychrophilic/mesophilic (P/M) zones of immature compost material and its growth potential correlated negatively with the maturity of the compost and the temperature within the simulated P/M zone. Significance and Impact of the Study: The risk of pathogen regrowth in P/M zones during organic waste composting further emphasizes the importance of good management practices and of avoiding P/M zones in combination with low compost maturity.

Composting for Avian Influenza Virus Elimination

“…Compost material is often nonhomogeneous, and this can result in an uneven temperature distribution throughout the compost pile, with parts, such as the surface, of the compost not maintaining thermophilic temperature (Ͼ50°C). If these parts of the compost are allowed to remain at a lower temperature than the rest of the compost pile, there is a risk of pathogen survival there during treatment (8). However, as demonstrated here, acceptable inactivation of H7N1 HPAIV can be achieved rapidly within the compost material even at mesophilic temperature (35°C) during the first stage.…”

Reduction of Bacteria in Relation to Feeding Regimes When Treating Aquaculture Waste in Fly Larvae Composting

“…moisture, temperature, and pH), even after the end of treatment (Soobhany et al, 2017). The degree of maturity of compost has been demonstrated by Elving et al (2010) to affect bacterial regrowth; they found negative correlations between the growth potential of Salmonella Typhimurium and the degree of maturity of an organic compost. The maturity of a material in a composting process (e.g.…”

Hygienization assessment during heap co-composting of Turkey manure and olive mill pomace

“…Actually, growing demand for sanitized compost is observed which reflects the increased interest in the food safety and environmental issues (Pandey et al, 2016;Soobhany et al, 2017). In certain cases, the remaining pathogenic organisms in a compost pile has been attributed to 3 main factors: inequal heating temperatures among different parts of the compost heap: The surface, the middle and the bottom of the piles (Aboutayeb, 2015); Mixtures inadequately homogenized as mentioned by Elving et al (2010), and cross-contamination due to infected working tools (Soobhany et al, 2017). Hygiene microbial indicators, such as faecal coliforms, E. coli and streptococci are generally monitored during the composting process to ensure compost quality production (Bustamante et al, 2008;Aboutayeb, 2015).…”