Text 6454, 72 rader
Skriven 2008-05-03 09:15:50 av Glen Jamieson
     Kommentar till en text av Joan Macdiarmid
Ärende: IRRADIATED FOODS   80503
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 -=> Quoting Joan Macdiarmid to Glen Jamieson <=-

Hello Joan,

 GJ> Irradiation:
 
 GJ> The usual food sterilizer is Gamma radiation, which is a
 GJ> non-particulate form of electro-magnetic radiation similar in
 GJ> wavelength to X-rays, and it leaves no residual radio-activity.

 JM> Yes, Jim made the observation that food irradiation
 JM> in Canada was either gamma, X-ray or, um, something
 JM> else, not UV. I was supposing high-intensity UV for
 JM> three reasons. First, that's what's used to keep the
 JM> labs used for cell-culture at the Uni sterile when
 JM> they are not occupied. And second, the cider, though
 JM> a bit murky as pressed, is not opaque, so a thin layer
 JM> passed under a high-intensity source should be
 JM> adequately treated. Third, I suspect high-intensity
 JM> UV is way cheaper than gamma or X-ray irradiation, and
 JM> several separate orchards represented at my Farmers
 JM> Market are offering this irradiated (not pasteurized)
 JM> cider, so whatever technology they are using must be
 JM> affordable or they are in a cooperative arrangement
 JM> to share the cost of the equipment.

UV sterilisers are cheap, and commonly used for "end of line" water
sterilisation as an alternative to chlorination.  As dissolved chlorine
retains a sterilising effect, it resists post-treatment contamination,
but UV treatment does not.  OTOH, UV treatment leaves no taste or odor.
Murky water (eg apple juice or treated waste water) has to be spread to
a thin layer to ensure the radiation penetrates effectively.

Gamma radiation, usually obtained from a radio-active isotope, easily
penetrates packets of meat or similar.  It requires a much more
expensive installation, with lots of lead to protect passers-by,  and
every few years, as the isotope loses its "kick", it has to be replaced
by a fresh source.
 
 JM> Another point I would make is that I have tried
 JM> the "irradiated" ground beef Wegman's sells at
 JM> a somewhat higher price, and it is definitely
 JM> better to my taste. I don't know what wavelength
 JM> of radiation was used to sterilize it, except
 JM> it wasn't ultraviolet, because UV won't penetrate
 
 GJ> I suggest that the irradiated meat tastes better than the usual minced
 GJ> (ground) meat because it doesn't have any nitrate or other
 GJ> preservatives added to give it an acceptable shelf life.

 JM> I don't think our ground meat includes extra
 JM> "ingredients", as that would have to be in
 JM> the labeling. (Inadvertent contamination is
 JM> not a deliberate ingredient.) I think the

Is there anything on the normal ground meat packages just given as
"preservative" or "colouring"?

 JM> meat is prepackaged, then irradiated to
 JM> sterility, and little more can happen to it
 JM> as long as it is sealed and refrigerated. This
 JM> includes no more exposure to oxygen after the
 JM> packaging, which probably has its own
 JM> degradative effect. Anyway, I did like the
 JM> product, though am less willing to pay the
 JM> higher price for it.

Does it have a longer storage life, as shown by a later "use by" date?
___ Blue Wave/DOS v2.30 [NR]

--- FLAME v2.0/b
 * Origin: Braintap BBS Adelaide Australia (3:800/449)