Impacts of sporulation temperature, exposure to compost matrix and temperature on survival of Bacillus cereus spores during livestock mortality composting

Abstract

Composting may be most appropriate for the disposal of carcasses infected with B. anthracis at ambient temperatures ≤20°C under thermophillic composting conditions (>55°C).

Heat and desiccation are the predominant factors affecting inactivation of Bacillus licheniformis and Bacillus thuringiensis spores during simulated composting

“…Vegetative growth of spores has also been noted in a previous study where compost reached temperatures above 55°C for <7 days and the number of spores of one strain of Bacillus cereus increased after 56 days composting (Stanford et al . ). Vegetative growth of B. anthracis outside of an animal host is likely insignificant (Bishop ) and limited differences in numbers of viable spores among Bacillus evaluated in the present study regardless of species, strain, heating matrix or sporulation temperature support the potential use of composting for disposal of anthrax mortalities.…”

“…; Stanford et al . ). Both of these field‐scale studies reported that the viability of spores during composting was correlated with compost temperature and duration of exposure to temperatures >55°C, but these findings were inconclusive due to variations in temperature distribution within the compost structures examined.…”

“…Due to limited sporulation at 10°C, livestock mortalities from anthrax at this or lower ambient temperatures would likely be of lower risk for disease transmission.number of nonpathogenic experimental surrogates have been evaluated, with spores of Bacillus thuringiensis gaining acceptance as an accurate model (Greenberg et al 2010;Bishop 2014).Previous investigations have shown that a number of infectious bacteria and viruses are killed during composting (Xu et al 2009a). More recent work using spores from Bacillus licheniformis and B. thuringiensis as surrogates for B. anthracis has also suggested that composting reduces numbers of viable spores (Reuter et al 2011;Stanford et al 2015). Both of these field-scale studies Journal of Applied Microbiology 120, 90--98…”

“…Previous investigations have shown that a number of infectious bacteria and viruses are killed during composting (Xu et al 2009a). More recent work using spores from Bacillus licheniformis and B. thuringiensis as surrogates for B. anthracis has also suggested that composting reduces numbers of viable spores (Reuter et al 2011;Stanford et al 2015). Both of these field-scale studies Journal of Applied Microbiology 120, 90--98…”

Assessment of Pathogen Inactivation under Sub-composting Temperature in Lab-scale Compost Piles

“…In general, composting process are used for treating organic waste including dairy, swine and chicken manure, green waste, food waste, and carcasses of poultry and livestock animals (Blake & Donald, 1992;Stanford, Reuter, Gilroyed, & McAllister, 2015;Yang, Hou, Zhai, & Zhang, 2015). In addition to producing organic fertilizer, composting of pig manure is reported to produce maggots, which is used as a feed supplement (Zhu et al, 2012).…”