Re: Food irradiation - what survival levels are aimed for?

["DAVE GILMORE" <DGILMORE@navajo.astate.edu>]

> From:          "Otto G. Raabe" <ograabe@ucdavis.edu>
 So, for example a dose of one
> kGy might reduce a particular bacterium by 10^6, but this would mean there
> would still be some (10^[-6])viable bacteria remaining. 

On millionth of one bacterium doesn't make a whole lot of sense.  I 
don't work in food microbiology, but I believe that when heat is used 
to pasteurize or sterilize, what's called the Decimal reduction Time 
(DRT) is utilized.  This is the time needed to reduce the population by 90% 
(an order of magnitude, as pointed out).  The particular DRT depends 
on the organism, conditions, and for heat, actual temperature.  I 
imagine that the same type of analysis is done for radiation.
10^[-6] makes sense as a _concentration_ if your units are ml and 
your volume is several thousand liters.
     I'm really getting an inkling to hit the journals;  this topic 
is so close to stuff I actually understand!


HANDBELL PEOPLE have all gone campan-

David F. Gilmore
Assistant Professor of Environmental Biology   
P.O. Box 599, Dept. of Biological Sciences  
Arkansas State University 
State University, AR 72467
dgilmore@navajo.astate.edu
ph  501-972-3082    fax 501-972-2638