[USCC] Composting Carcasses in Windrows

[Helane Shields]

This is to respond to Ken Powells post regarding composting animal carcasses and the "SRM issue"..     SRM = 'specified risk materials' -  the  parts of the animals most likely to contain prion infected wastes:



Many experts, including the US Environmental Protection Agency, say composting prion infected wastes is futile - the temperatures are not high enough, the prions survive,  and landspreading this infected compost can put more animals at risk:

EPA Region 8:  "Common methods of waste treatment in sewage treatment plants, or publicly owned treatment works 
(POTWs), and septic systems, as well as landfilling and composting, are ineffective at completely inactivating TSE 
agents (Prusiner 1982; Bellinger-Kawahara et al. 1987; Manuelidis 1997; Taylor 2000; Taylor 2001). . ."

National Renderers Assoc. response to USDA and APHIS, June 2005:  "While finished compost can be spread on crop 
ground as fertilizer, if prions are present and the compost is used as fertilizer prions can re-enter the food chain through grazing plants and hay and straw obtained from those. Thus, composting should not be used to dispose of CWD deer and elk, sheep and goats with scrapie or cattle with BSE. Composting is especially unsuitable for specified risk materials, especially neural tissues (skull and spinal cord) encased in bones (ref.11). The indiscriminate use of composting and spreading its by-products on agricultural land is inconsistent with the FDA feed rule, would dilute its integrity and invalidate all existing BSE/TSE risk assessment models (ref.8). This is similar to what may have transpired with the CWD material, given the WIDNR disposal policy (refer to 2.3. Controlled Land Fill) was indeed implemented. "

Dr. Paul Gale, UK, DEFRA, May 2002:  " "BSE and scrapie prions and C. botulinum spores are excluded because for 
the purposes of risk assessment they are considered not to be affected by the temperatures achievable by composting 
and biogas processes."

Iowa State:  " Due to many unknown factors regarding the biodegradability of the prions that cause bovine spongiform 
encephalopathy (commonly called BSE or "mad cow" disease), composting should NOT be used for disposal of cattle 
suspected to have BSE."

APHIS/USDA - Jan. 2005:  Anaerobic digestion (of carcasses ). . . "it is necessary to use additional heat at the end of 
the process to fully inactivate pathogens.  However, even with this, prions are not inactivated."


US EPA:  "Prions are extremely resistant to inactivation by ultraviolet light, irradiation, boiling, dry heat, formaline, 
freezing, drying and changes in pH. Methods for inactivating prions in infected tissues or wastes include incineration at 
very high temperatures and alkaline hydrolysis. "


http://www.sludgevictims.com/pathogens/prions-composting.html

Further,  prions can survive for years in soils, and Dr. Joel Pedersen,et al,  Wisconsin State, found that soil can increase the infectivity by a factor of 680.

Helane Shields, Alton, NH