Return to BigSpud Menu

Subject: Potato Question


From: David Fulford-Brown <nospam-david.fulford-brown[at]>
Date: Wed, 22 May 2002 20:08:37 +0100

Can anyone tell me please, when potatoes start growing the little tube
things (sorry, don't know what they're called), are they still safe to
eat?  Likewise, we have green coloured potatoes.  Are they still ok to

Thanks for your help.

David F-B


From: Peter Aitken <paitken[at]>
Date: Wed, 22 May 2002 19:17:28 GMT
THe sprouted potatoes are safe but in my experience are usually past their
prime and do not taste that great. You should not eat the sprouts themselves
but trim them off as well as the section they are growing from. Green
potatoes should be avoided. The green areas taste bitter and contain
solanine, which is toxic.


From: nancree[at] (Nancree)
Date: 22 May 2002 19:58:03 GMT
Food Science Australia Fact Sheet

February 1994

Greening of potatoes

Why do potatoes turn green?

The role of a potato tuber for the potato plant is to produce the next
generation of potatoes. It therefore contains nutrients in the form of
starches, sugars, proteins and minerals for the new potato plant. When a potato
tuber is exposed to light it turns green by producing chlorophyll and then can
make extra energy for the new plant through photosynthesis. The green patches
act in the same way as leaves do.

The potato plant also has the interesting ability to produce its own protective
chemicals which can make it lethal to insects, animals and fungi which attack
it. These protective chemicals (glycoalkaloids) are at high levels in the
leaves, stems and sprouts of the potato plant and are normally at very low
levels in potato tubers. However on exposure to light the potato tuber will
produce elevated levels of these protective glycoalkaloids, with the highest
levels being in the sprouts as they emerge from the tuber.

Potatoes will also produce high levels of glycoalkaloids (such as solanine) in
response to bruising, cutting and other forms of physical damage, as well as to
rotting caused by fungi or bacteria. In these instances high levels of
glycoalkaloids are present in the potato. However in non-damaged potatoes,
greening is a warning sign.

Are green potatoes safe to eat?

Green potatoes may cause food poisoning and since some of the symptoms are
similar to gastroenteritis it is possible that some undiagnosed cases of
gastroenteritis have been caused by eating green potatoes.

Human and livestock deaths have been recorded as a result of the consumption of
greened or damaged potatoes with very high glycoalkaloid levels. It should be
noted that glycoalkaloids are not destroyed by cooking processes, even by
frying in hot oil. Consequently potatoes with pronounced greening or with signs
of damage should not be eaten.

It is advisable that green or damaged potatoes are avoided by pregnant women or
women who are likely to become pregnant, as there is some evidence of possible
foetal damage or loss of the foetus from glycoalkaloid poisoning in animals. 


From: Peg Haine <mlh4[at]>
Date: Wed, 22 May 2002 16:06:46 -0400

When potato eyes begin to sprout, the spuds are still OK to eat, as long
as they're not mushy.  But you don't want to eat either those sprouted
eyes or any skin that's turned green.  Remove both before cooking.  I
can't remember what the chemical is that's included in both those parts,
but it'll give you one hell of a bellyache.

Return to BigSpud Menu