On Sun, 25 Oct 2009 13:20:09 -0800, Mark Thorson >
wrote:

>Kswck wrote:
>>
>> "john royce" > wrote in message
>> ...
>> > When I steep chopped garlic pieces in Japanese rice vinegar for a few
>> > days, they stay the same colour. When doing so in Tesco's Chinese rice
>> > vinegar they turn bright green blue. What would be the likely difference
>> > in the two vinegar's?
>> >
>> I was always told not to steep garlic in oil due to a possibility of
>> botulism-but I am not sure it applies to vinegar as well.
>
>It doesn't. Oil cuts off access to oxygen,
>which allows poisonous anaerobic bacteria
>to grow. Vinegar doesn't do that.

As I understand it, steeping fresh garlic in vinegar does prevent the
growth of Clostridium botulinum spores but, not because it is an
anaerobic environment.
Conditions that favour the production of botulism toxin are, high
humidity, low salt, low acid and lack of oxygen.
Steeping fresh garlic in oil provides all these conditions.
Steeping in vinegar effectively eliminates the low acid requirement.

Ross.