Re: [Fwd: Cooking in a Compost Pile]

Myra Nissen (
Fri, 22 Jan 1999 00:23:34 -0800

Sorry that this is coming so late. I wanted to have a friend of mine
comment on the topic of cooking in a compost pile. She has a degree in
agriculture and has worked a lot in composting.

Myra Nissen

Here is her reply:

While many foods can be "cooked” using the heat of composting, it is
usually not going to be sufficient to properly disinfect contaminated
food. If you are concerned about pathogens such as e-coli in meat,
salmonella in eggs or poultry, etc., it would be very wise to resist the
urge to consider mere heat coaguation of these foods as "cooking" in the
sense that there has been significant pathogen kill. Indeed, pathogen
counts may increase because at the relatively low temperatures in a
compost "oven" and the length of time involved to complete the
denaturation of tissue protein (which we think of as cooking), bacteria,
particularly heat labile organisms or heat labile toxins (such as
botulinin) may increase and be more dangerous than if the food was
consumed raw. Regarding bacterial survival in a vermicomposting system,
it is always smart to remind kids not to put their hands in their mouths
or eyes while tending a worm bin. Wash up when done, naturally. But the
worm gut is not the only method of pathogen destruction at work, either
in a cold or a hot system. It appears that pathogen destruction is
reasonably thorough in worm composting systems (articles in Biocycle,
Water Federation and other trade journals). The competition from
bacteria and unicellulars who thrive in the habitat of a compost system
has huge impact on the survival of pathogens who are not happy with the
environment of a healthy well aerated compost system. Counts and
survival surveys indicate very thorough destruction of all enteric
organisms including salmonella, listeria, e-coli, clostridium, various
worms such as tapeworm and roundworm, hepatitis virus etc. There will
always be a few, and the chance of an infectious dose exists, but the
odds are very much against a normal person becoming infected through
contact, even prolonged contact, with a well managed, aerobic compost
system. Infectious dose is defined as sufficient numbers of viable
organism to cause sickness in a normally healthy person. Immune
compromised individuals, children, or sick people may be at risk from a
smaller dose than a healthy person. Judgment is in order. Wash hands
after tending, before eating. Actual studies show finished compost from
a well managed, aerobic hot pile to have counts of viable pathogens
comparable to swimming pools, pasteurized bulk milk, and much lower than
counts obtained in most hospital operating rooms!