[USCC] Fecal coliform

[epsteinee@comcast.net]

List service members,

E.coli 0157:H7 will be destroyed by the composting temperatures if the time-temperature regime as stated in the USEPA 503 regulations are met. The heat inactivation of coliform bacteria in composted biosolids was 10 to the minus 2 in 12 minutes at 55C. At 61C the heat inactivation was 10 to the minus 6 in 25 minutes. The longer the composting time in which temperatures reach 55C the better the potential for inactivation of E.coli. There is no reason to assume that E.coli o157:H7 would have a higher temperature or exposure time that other coliform bacteria. Just to give an example as to the importance of time-temperature, heating of milk to 60-63C for 20-30 minutes results in pasteurization and destruction of pathogenic bacteria.
The destruction of pathogenic organisms during composting is further enhanced by the release of ammonia, a disinfectant.  Data by Pat Millner of USDA also showed that salmonellae are destroyed by compost microflora. One of the best papers on pathogen destruction was by Walke in 1975. He found that E.coli, Salmonella eidleberg and Candia albicans containing 1 million organisms initially in bark-biosolids compost were not detected after 36 hours of windrow composting. There are many other papers as sited in my book, The Science of Composting.  
Walke, R. 1975. The preparation,charaterizationn and agricultural use of bark-sludge compost. Ph.D., University of New Hampshire, Durham, NH.
It is important to avoid regrowth or recontamination. Regrowth control is achieved by removing the food source. This is done by curing to achieve a highly stabilized product.

Manure to be used for growing food crops should be composted properly. Even individual farmers can achieve proper composting using passive or active aeration or windrow composting using farm equipment. There have been several incidences of e.coli O157:H7 contamination of foods as a result of raw manure contamination.

The incidences of spinach contamination which most likely was the result of runoff or contamination of the water supply was similar to the incident whichoccurredd in Milwakee where over 100,000 persons became sick and over 100 died as a result of cryptosporidiumcontaminationn of the water supply. There was somediscrepancyy as to the cause whether it was human waste or animal waste contamination by runoff of the water supply. Ibeleivee that animal waste was most likely the source since calves and cattle will shed hundreds or thousands of cryptosporidum cysts in their feces. This points out the importance of preventing runoff from farms and even composting facilities.

Leachate or runoff from composting facilities should either be treated or contained.  

Since I have been involved in several hundred composting operations, I found that my clients have achieved excellent pathogen destruction when achieving proper composting and curing and avoiding re-contamination by either cleaning equipment or usingseparatee equipment for the feedstocks and the final product.

We are planning to have a special session on this subject as well as sampling and analysis of pathogenic and indicator organisms at the USCC conference in Orlando. A special announcement will be forthcoming.

Eliot Epstein
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Eliot Epstein 
19 Preston Place 
North Easton, MA 02356 
Tel: 508-238-1631 
Cell: 781-603-7151 
E-mail: epsteinee at comcast.net