Thread: Questions of life-roast beef

On Jul 22, 7:52*pm, angie-...@webtv.net (z z) wrote:
> What exactly is that green iridescent sheen on slices of roast beef?
> I've seen it a million times at the work cafeteria and I dont buy their
> beef anymore because it is repugnant to me, though apparently considered
> edible. This wkend it was on the slices of roast beef bought at our
> "premium" grocery store meat counter.

Your tax dollars at work:

9. What causes iridescent colors on meats?
Meat contains iron, fat, and other compounds. When light hits a slice
of meat, it splits into colors like a rainbow. There are various
pigments in meat compounds that can give it an iridescent or greenish
cast when exposed to heat and processing. Wrapping the meat in
airtight packages and storing it away from light will help prevent
this situation. Iridescence does not represent decreased quality or
safety of the meat.

"z z" <[email protected]> wrote in message
news:[email protected]..
> What exactly is that green iridescent sheen on slices of roast beef?
> I've seen it a million times at the work cafeteria and I dont buy their
> beef anymore because it is repugnant to me, though apparently considered
> edible. This wkend it was on the slices of roast beef bought at our
> "premium" grocery store meat counter.

Good question. I have seen it on very expensive organic beef but didn't
know what it was.

On Sun, 22 Jul 2012 20:37:10 -0700 (PDT), spamtrap1888 wrote:

> 9. What causes iridescent colors on meats?
> Meat contains iron, fat, and other compounds. When light hits a slice
> of meat, it splits into colors like a rainbow. There are various
> pigments in meat compounds that can give it an iridescent or greenish
> cast when exposed to heat and processing. Wrapping the meat in
> airtight packages and storing it away from light will help prevent
> this situation. Iridescence does not represent decreased quality or
> safety of the meat.

Any time I see that iridescent sheen it always means it's past it's
prime. Especially in sliced deli meats - the smoother the surface the
more apparent it is, but it doesn't show up for a few days - has been
my experience with buying deli roast beef (although rare).

-sw

On Sun, 22 Jul 2012 21:52:40 -0500, [email protected] (z z) wrote:

>What exactly is that green iridescent sheen on slices of roast beef?
>I've seen it a million times at the work cafeteria and I dont buy their
>beef anymore because it is repugnant to me, though apparently considered
>edible. This wkend it was on the slices of roast beef bought at our
>"premium" grocery store meat counter.

It's light refraction of various compounds in the meat fluids. (I want
to say blood, but am trying to be sensitive to the ick factor in some
people) It does not mean the meat is spoiled.
Janet US

On Sun, 22 Jul 2012 21:52:40 -0500, [email protected] (z z) wrote:

>What exactly is that green iridescent sheen on slices of roast beef?
>I've seen it a million times at the work cafeteria and I dont buy their
>beef anymore because it is repugnant to me, though apparently considered
>edible. This wkend it was on the slices of roast beef bought at our
>"premium" grocery store meat counter.

That irridescent rainbow effect is caused by the type of lighting
used, delis and meat departments typically illuminate meat with a lamp
of a particular spectrum that enhances the appearence of meat,
typically more red... meats actually fall into the grey scale, it's
only lighting that gives it that attractive red color by a prismatic
effect, just like fish scale and bird feather coloration is prismatic
so are cell walls of flesh, not due to pigmentation. As the surface
of meats dry the prismatic effect is more pronounced, same as wet
birds look dull but once dry their color appears more pronounced.
Anyone who has a home aquarium knows that their fish exhibit no color
until the tank is lit. The coloration of objects is determined by
what our eyes transmit to our brains, everyone sees color differently.

On 7/22/2012 8:52 PM, z z wrote:
> What exactly is that green iridescent sheen on slices of roast beef?
> I've seen it a million times at the work cafeteria and I dont buy their
> beef anymore because it is repugnant to me, though apparently considered
> edible. This wkend it was on the slices of roast beef bought at our
> "premium" grocery store meat counter.
>


A reply from Google/Yahoo from 2006:

"It means nothing. Its totally normal and its called birefringence.

Here's the deal. The cut surface of meat is pretty smooth. But, if you
look closely, you'll see it's actually a vast landscape of parallel
fibers. When cut, the reduced surface pressure coaxes microscopic beads
of moisture to the surface, each one of which acts as an independent
prism. When viewed in concert, they look like a rainbow."



gloria p