Irradiation of food

[keith.millington@tft.csiro.au]

Hi Neil,

Your reply to my posting raises some interesting points. 
I would agree that in permeable, heavily hydrated substrates (textiles,
foodstuffs, whatever) one would expect radical lifetimes in general to be
very short. However there is also the possibility of undesirable products
being formed from the reaction of free radical species produced during food
irradiation with dissolved or atmospheric oxygen (O2 is effectively a
radical species, having two unpaired electrons, and reacts readily with free
radicals). Oxidation of perishable foodstuffs is clearly a factor which
determines their acceptable shelflives. Is there any data comparing
oxidation rates of irradiated perishable foodstuffs with controls ? Can
increased rates of oxidation after irradiation affect taste, appearance,
consistency etc ? I note that in our studies, irradiated wool contains
higher levels of oxidation products ( in particular cysteic acid, derived
from cysine residues in the protein strucure of wool keratin) than control
samples, measured by FTIR and XPS. 
You estimate that hydrated meat contains 70-90 % water. I guess water
contents of dried meats (eg salami, smallgoods etc) will be significantly
less than this. You may not be aware that wool under normal atmospheric
humidity conditions always contains about 15% water, yet wool still exhibits
a natural esr spectrum showing the presence of free radicals even in the
presence of water.
I like your line about orange sweaters and apples - but maybe the
perspective is a little different for moth larvae and carpet beetles, etc .
Only kidding ! 
If you are interested in the paper I mentioned, I can send you a Word
documents of the accepted draft.

Regards, Keith

Dr Keith R Millington,
Project Leader, Textile Photochemistry,
CSIRO Textile and Fibre Technology,
PO Box 21, Belmont, VIC 3216.
AUSTRALIA.
ph: 0352-464792
fax: 0352-464057

************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html