RE: Fwd:New York Times - Red Meat Irradiation Rules

["Weiner, Ruth" <rfweine@sandia.gov>]

Thank you Dr. Claycamp for your explanation of the two processes.

Ruth F. Weiner, Ph. D.
Sandia National Laboratories 
MS 0718, POB 5800
Albuquerque, NM 87185-0718
505-844-4791; fax 505-844-0244
rfweine@sandia.gov


-----Original Message-----
From: Gregg Claycamp [mailto:hgc2+@pitt.edu]
Sent: Saturday, February 13, 1999 7:59 AM
To: Multiple recipients of list
Subject: Re: Fwd:New York Times - Red Meat Irradiation Rules 


The notion that one could equate acquisition of antibiotic resistance and a
future radiation resistant bacterium is scientifically flawed for many
reasons:

1.    The mechanisms of action are not the same.  Most antibiotics interfere
with fission (bacterial division, not nuclear!).  The cells are more
vulnerable to attack during this stage giving the body time to catch up with
the infection in addition to simply wearing down the bacteria population.
Selection of bacterial resistance genes occurs with repeated under-dosing
(patients don't comply with prescriptions) much like natural selection.
Once that a resistant cell grows, the infected patient provides a medium for
expansion of the population.  From there, hospitals are usually great places
to expand the population from host-to-host  (ie, there are lots of sick
people at hospitals, and hygiene among care-giving staff is not perfect).

This is not the same as giving lethal --not just division-inhibiting-- doses
of radiation to small populations of bacteria contaminating meat.  Here, a
rare surviving bacteria cell is likely to die during cooking or consumption.
The idea is to lower the population number (if it's there in the first
place) low enough or "zero" that a significant regrowth and human infection
is unlikely, given proper food handling.   (We consume microbes every
day--normal biology and proper food handling keeps things in check.)

2.  
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