Salmonella are very similar to the E. coli that we work with in our lab
(no, not the strains that make people sick, just harmless lab strains used
for molecular genetics research). All these bacteria can survive for long
times if they're kept moist, and bird droppings probably make about as
good a culture medium as the broths and agars we make. Our low winter
temperatures tend to preserve them; excess heat will kill them, and so
will drying. But bacteria die exponentially, just as they grow
exponentially. They don't just all die at once, unless you really
incinerate them, and heating and drying just change the slope of the death
curve. So if you had 10 to the 8th or 10 to 9th bacteria contaminating a
feeder (not unreasonable numbers) and just depended on drying to kill
them, well, who knows? . . . in a week they might have died down to 10 or
100 survivors, but those few will grow up mighty fast in better conditions,
and it only takes one to start an infection. I'd disinfect.

Burt Guttman guttmanb at elwha.evergreen.edu
The Evergreen State College Voice: 360-866-6000, x. 6755
Olympia, WA 98505 FAX: 360-866-6794

On Sun, 22 Jan 1995, Dean Schwickerath wrote:

> Can Salmonella survive being dried out? Put another way, if you rotated bird
> feeders and placed the unused feeders in a dry heated area do the salmonella
> bacteria survive? Just wondering if people can rotate feeders and save some
> work washing each feeder out with a light bleach solution on a weekly basis.
> We already wash the bird bath each week but will add a small amount of
> bleach in the future. I am considering a second bird bath to also rotate use
> of that device. We will also move the feeding area around so the same ground
> isn't being used constantly but I was wondering if the nightly racoon raid
> on the ground seeds might reduce salmonella problems?