On 3 Sep 2007 at 13:55, [log in to unmask] wrote:


> Is there any [well controlled] study that demonstrated that [few or many] b. spores in raw 
> honey caused the onset of botulism in a healthy infant while there were no other such 
> sources of the b. spores as you mention?
> Waldemar   
Waldemar

Here is a quote from the report I referenced in an earlier post:

Estimates from the literature of the minimum infectious dose
6.1 Proteolytic Clostridium botulinum has been identified as the agent
responsible for most cases of infant botulism. Neurotoxigenic strains of
C. baratii and C. butyricum have occasionally also been responsible for
cases of infant botulism.
6.2 Information from the literature on the minimum infectious dose is
extremely sparse. A commonly cited estimate is that the minimum infectious
dose is 10-100 spores. This estimate is based on reports that honey
samples that have been associated with infant botulism contain 5-25 spores
per g, and 5-70 spores per g. Sugiyama et al estimated that the highest
concentration of spores in honey not associated with infant botulism cases
was 7 spores per 25g.


The figure of 10-100 spores look like a best guess on the basis of not a lot of 
information

Best wishes

Mike Rowbottom


HARROGATE
North Yorks
UK

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