Source of bad smells: rotten eggs,skunk cabbage, etc.

Andre Burnens BURNENS at VBI.unibe.ch
Mon Nov 18 12:31:25 EST 1996

Hugh Vartanian wrote:
> Hi
> I'm writing a children's book on gross smells.  One of the premises of the
> book is to provide a scientific explanation of the sources of such everyday
> unpleasant odors such as rotten eggs (I kind of doubt it is hydrogen sulfide
> or that the yellow of egg yolks is from sulfur), skunk cabbage (perhaps I
> should check the botanical sources?), sour milk, etc.  I have a handle on the
> basic function of the olfactory system, but am at a loss to find
> information on this stuff.  Is it bacterial fecal matter that causes the odors
> or what?
> Any thoughts would be greatly appreciated.
> Thanks,
> Luann
> luann1212 at aol.com

Very often the products of bacterial metabolism have a bad smell. I am 
unaware of a systematic study on this and on the compounds involved. 
However, hydrogen sulfide can be produced through reduction of the -SH 
functional group in the amino acid cysteine (present in many proteins) by 
bacteria. _Anaerobic_ decomposition very often produces bad smells, e.g. 
short chain volatile fatty acids, some of the endproducts of 
their metabolism. Complete, i.e. aerobic degradation (like a 
well-ventilated compost heap), produces less bad smell.

Andre P. Burnens MD
National Reference Laboratory for Foodborne Diseases
Institute for Veterinary Bacteriology, University of Berne
Laenggass-Strasse 122, CH-3012 Berne, Switzerland

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