From: John De Armond Newsgroups: misc.consumers.frugal-living Subject: Re: Frugal university lunch ideas Date: Sat, 15 Oct 2005 15:04:06 -0400 Message-ID: <m9k2l1tjmplbme7inbqtshcaqbhhh5f5gi@4ax.com> On 15 Oct 2005 10:54:02 -0700, "JeffM" <jeffm_@email.com> wrote: >>>Those unfrozen microwave entrees >>> Chloe >> >>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. >http://www.google.com/search?q=food-irradiation+Cesium 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 production reactors. 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 beam. 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 :-) John |