From: John De Armond
Subject: Re: Frugal university lunch ideas
Date: Sat, 15 Oct 2005 15:04:06 -0400
On 15 Oct 2005 10:54:02 -0700, "JeffM" <email@example.com> wrote:
>>>Those unfrozen microwave entrees
>>The ones I am referring to are made by Hormel,
>>don't need refrigeration
>> Ron Peterson
>The method of preservation is exposure to Cesium 137.
>As the gamma rays pass thru the food (leaving no residual),
>they zap all the little critters.
Cs-137 isn't used much anymore for radiation sterilization, being
replaced by accelerator-generated electron and X-ray irradiation.
Cs-137 has fallen out of favor because it can't be turned off, it
requires expensive shielding for storage, periodic leak testing is
required of the sources, cesium chloride, the usual chemical compound,
is hard on the encapsulation material, leading to frequent leakage,
the half-life is fairly short and finally, because supplies are
dwindling since the end of the cold war and the shutdown of Pu
An additional feature of accelerators is that they can produce much
more radiation than any reasonably sized Cs-137 source. A LINAC the
size of a car can generate many tens of amps equivalent of electron
That big source leak at the medical sterilization facility in Atlanta
about 15 years ago was the catalyst for the move to accelerators.
No idea if the Hormel products are radiation sterilized or merely
ultra-pasteurized but I thought I'd do that mini-brain dump :-)