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THE LAST WORDEggstraordinary
claim
I’ve just read that eggs should not be
stored in a rack on the back of a fridge
door, the exact place where most
fridge manufacturers put the egg
rack. Before I revamp my fridge,
is there any truth to this? And if so,
what could it be?Q Once an unfertilised egg drops
out of the back of a chicken, it
crosses the road towards decay.
This is because chick embryos
need to breathe, so eggs must be
gas-permeable. Even in the
absence of an embryo, carbon
dioxide diffuses out through the
shell, and this makes the interior
less acidic. Water from the white,
or albumen, also diffuses outwards
and, by osmosis, into the yolk.
The egg white thus becomes
inhospitable to healthy proteins,which have a naturally folded
structure that depends on the
local acidity. This in turn swells
the yolk and makes membrane
more fragile. If you ever try to
make a soufflé using old eggs, you
will find that the whites and yolks
have become inseparable.
All these processes speed up
with temperature, so storing eggs
in the fridge is a good start. But an
open rack behind the door is not
the best spot. When you open the
fridge, you waft fresh, warm airover any layer of carbon dioxide
that has built up at the egg’s
surface. This encourages yet more
diffusion out of the egg, and thus
yet more ageing. You also tend to
shake the eggs, resulting in a more
watery albumen by mixing the
thick and thin components of
the white.
The best place in the fridge to
store eggs is probably in a sealed
box, to prevent diffusion, and as
low down as possible – in other
words, in the coolest part. This
slows the loss of carbon dioxide
and water to the air, and also
prevents the egg taking up odours
from inside the fridge.
It is worth remembering that
eggs emerge from a contaminated
part of a bird’s anatomy, so
routinely harbour bacteria,
notably Salmonella enteritidis.
A sealed box would stop egg-
winds wafting over the other
contents of your fridge. We should
also clean the egg rack regularly,
wherever in the fridge it may be.
I wonder if fridge-makers
originally put egg racks inside the
doors because they could not
think what else to use these tiny
spaces for.
Simon Goodman
Griesheim, GermanyQ^ Eggs can be stored in the fridge,
preferably in a box to slow water
loss, but they should be taken
out and allowed to reach room
temperature before cooking. This
is important if you like a soft yolk:
oeufs en cocotte and eggs sunny
side up don’t work otherwise,
because when the white is cooked,the yolk is still only lukewarm.
I learned this back in the 60s
when working as a short-order
chef at a motorway services,
where I also learned to crack
eggs single-handed.
Luce Gilmore
Cambridge, UKClean cut
Every so often, my adopted cat brings
home geckos in two pieces, namely
the still-moving tail and the rest of the
body (also still moving). But there is
never any obvious blood. Why?Q Wild animals often must
recover from severe injuries,
or die. Where we live, I am
repeatedly amazed to see game
birds survive incidental injuries
and regain normal use of loosely
flapping broken legs or wings
that had been very crooked.
The realities of natural
selection are so extreme that
many snakes, insects, fish or birds
have developed highly effective
self-healing abilities. As a result,
they can afford to try to redirect
attacks towards non-critical areas
at their rear, in particular frills of
hair, loosely set feathers, fake
heads – or, indeed, sacrificial tails.
Some animals even use their tail
non-sacrificially to attract prey.
Many lizards have more or less
fragile tails that distract predators
by thrashing when broken off. If
alarmed, some geckoes drop their
tail whether or not something is
tugging at it, an example of what
is known as autotomy.We pay £25 for every answer
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newscientist.com/lastword/“ Did fridge-makers put egg
racks inside fridge doors
because they did not know
how else to use the space?”
A tail is a major investment,
served by its own artery. Letting
it bleed would be fatal, so muscles
at intervals along the blood
vessels clamp the flow, and the
blood clots rapidly. It is something
surgeons can only envy.
Jon Richfield
Somerset West, South AfricaQ Many lizards and geckos
display this behaviour, which is
known as autotomy. Where I live,
there are no geckos but lots of
wall lizards, which shelter in and
around the garden. Occasionally,
just moving one of my outside
bins will reveal a wriggling tail,
the startled lizard having
made off.
My cat loves hunting lizards
and has brought in tails –
although less often now – but
never both the tail and its owner
together. The lizards do grow a
new tail, but it lacks vertebrae
and clearly doesn’t match the
rest of the body.
Terence Hollingworth
Blagnac, FranceQ In Hawaii, I see geckos hunted
by cattle egrets (both are invasive
species there). The egrets walk
on the tops of hedges and reach
down to grab geckos with their
beak. If one gets hold of the tail, I
frequently see the gecko fall away,
leaving the egret with only a tail
in its mouth. If it grabs the body,
the egret must still twist the gecko
90 degrees to swallow it, and so
may still end up with just the tail.
Stephen Johnson
Eugene, Oregon, US