Some more questions from student via email

Dear Prof Kwan,

Thanks for your reply. But I have further questions as below. Please kindly
help. Thanks a lot.

1)It is known that the temp of thermophile C. perfringens is 42-47C, but how
about the temp range of mesophile C. botulinum?

A: C. botulinum has optimum temperature of 26-35C.

2)The endospore of C. botulinum is most heat resistant, nearly the last one to
die during cooking, but how come the neurotoxin(heat liable protein)it produced
cannot be eliminated by cooking(as need to be killed by canning which need much
higher temp)?

A: Canning aims to kill the C. botulinum endospores, not the neurotoxins. The neurotoxins are heat sensitive.

3)what organism is mostly grow in red wine based on below condition? (as
yeast/fungi seem cannot grow in high Aw (0.99))

Red wine:
Water Activity     0.99
pH                 4.5
NaCl content w/v           0.5%
Redox (mV)         350
Sugar content      Moderate
Protein content    Low
Keeping temperature 25C

A: Yeasts and fungi can grow at high Aw. Acetic acid bacteria can grow in red wine. But this group of bacteria was not covered in our lectures.