RE: New York Times - Red Meat Irradiation Rules

[Joe Provost <provost@mhd1.moorhead.msus.edu>]

>Would anyone care to comment on this statement?

>>But its lasting efficacy is being debated. Ms. Foreman, who says there
>>is a place for irradiated foods in nursing homes and hospitals, warns
>>that "in the long run, years out, bacteria are likely to develop
>>resistance to irradiation," just as they have to one antibiotic after
>>another.

Resistance of bacteria is due to a gained ability to grow and multiply in
the presence of an antibiotic or other environmental stress.  This is of
course due to alterations in the genome of the bacteria which will result
in a modified protein whose function is to overcome the new stress.  For
example, ampicilin resistance is due to the ability of E. coli to either
hydrolyze the ampicilin (so that the cells maintain the ability to cross
link and strengthen the cell wall) or to lose the ability for the
crosslinking enzyme to be inhibited by ampicilin.

Note that the mutations (which are brought about by several different
mechanisms) result in changes that allow the cell to grow.  The damage
brought about by irradiation is of a totally different nature.  Any
resistance would have to come from a very enhanced ability to deal with the
free radicals, the damage to proteins and lipids and to have a DNA repair
mechanism that is beyond belief.

It is likely that low level radiation would create a mutant strain.  If E.
coli were to survive they could gain an interesting new phenotype however
if all of the cells were killed then this would not be a problem.  It is
highly unlikely that a stain would be able to gain the ability to survive
irradiation


>

Joe Provost
Dept of Chemistry
Moorhead State University
Moorhead MN 56563
218-287-5085


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