Subject: Re: Potato poisoning
From: mannj@southern.co.nz (Jay Mann)
Date: Feb 25 1996
Newsgroups: sci.med

ORA ROYCE (newarktm@ix.netcom.com) wrote:
: In <4gl5as$pdh@leol.net-link.net> "Jay R. Roder"
: >I'm a paramedic and am looking for info on potato poisoning. Fact or
: >falicy? What portion of the plant is toxic?  What are the S/S of it?
: >
:  I don't know the symptoms but I do know that when potatoes are stored
: where they are exposed to sunlight they will turn green.   This is
: poisonous - I don't know how poisonous, but they taste terrible and
: should not be eaten. If your potatoes are green they should be
: discarded.  Store them in a dark place away from sunlight. : 
: Also potatoes which have started to sprout should not be eaten.

Quite right.  The toxic chemical is solanine, a glycoalkaloid, which 
acts as a cholinesterase inhibitor.  This is the same action as nerve 
gases.   The taste is said to be terrible, in the back of the mouth.  
Mild doses cause headaches, severe doses death.  Most human casualties 
have occurred in cases where eating bad potatoes was not optional: 
starvation, prison camps, boarding schools (but I repeat myself).  
Supposedly fierce curries can also disguise the taste.

The green colour is not itself toxic, but indicates that the potatoes 
have been exposed to an environment that is likely to have triggered 
solanine production.  Sprouting, too, can trigger solanine production.  
Some potato varieties, no longer grown, could make excess solanine during 
unusual growing seasons without any external greening.

: Sweet potato plants can develop a fungus, (I can't remember the name
: but it is poisonous but is also used as a drug).

Ipomeanol, which is probably made by the fungus (Fusarium, I think) as a 
way to detoxify the ipomeanone.  Ipomeanone is an antibiotic chemical 
made by the sweet potato. So successful fungi have to overcome the 
ipomeanone.  Ipomeanol is harmless in most animal organs, except that 
when it reaches the lungs it is converted into a tissue-damaging 
derivative.  Therefore ipomeanol has been investigated as a targeted drug 
for treatment of lung cancer.

Jay D Mann  <mannj@southern.co.nz>
Christchurch, New Zealand

Subject: Re: nightshades?
From: mannj@southern.co.nz (Jay Mann)
Date: Sep 26 1996
Newsgroups: alt.agriculture.fruit,alt.food.professionals,rec.food.cooking,
	rec.food.historic,sci.bio.food-science

Jack Campin (jack@purr.demon.co.uk) wrote:
: 
: leecheng@wizard.net (Clifford Eng) writes:
: > Some years ago, I read in a book on wild edibles that Solanum nigrum
: > (deadly nightshade) is edible if cooked. the author had a recipe for pie. 

 Solanum nigrum is black nightshade, a relatively harmless fruit.  I've 
worked with Solanum laciniatum and Solanum aviculare, which have toxic 
glycoalkaloids in unripe fruit, but which were used by settlers to make 
bland but harmless jams with when fully ripe.  I'm also pretty certain 
that green tomatoes are quite high in tomatine, another glycoalkaloid.  
Potatoes contain solanine-based alkaloids, which are chemically similar 
to the tomato chemicals.  All are, I believe, mild inhibitors of choline 
esterase, that is, they act like nerve gases.  One lady who 
professionally investigates potato alkaloids reported that a 
high-alkaloid strain of potatoes gave a back-of-the-throat bitterness, 
followed by a violent headache the next day.  But she forced herself to 
eat more of these potatoes than anyone else would.

Everyone who includes potatoes in their diet has, I've read, detectable 
levels of solanine in their blood.  About ten years ago there was a 
read-me-and-shiver book on the purported risks of eating solanaceous 
plants (tomatoes, eggplants, and potatoes) for certain people.  I suspect 
this book is the source of the current fears about tomato eating.

Someone in this thread suggested that modern cultivars have been bred for 
lower toxin levels.  That's probably quite true; certainly modern 
eggplants usually don't need the salt extraction method to remove 
bitterness.  (Personally I still use salt pretreatment because the bitter 
fruits are visually indistinguishable from non-bitter ones.)  There was 
great resistance even to the consumption of potatoes when they were first 
introduced to Europe, and it took considerable effort by Count Rumford to 
popularise them.

Jay D Mann  <mannj@southern.co.nz>
Christchurch, New Zealand

Subject: Re: nightshades?
From: mannj@southern.co.nz (Jay Mann)
Date: Oct 04 1996
Newsgroups: alt.agriculture.fruit,alt.food.professionals,rec.food.cooking,
	rec.food.historic,sci.bio.food-science

While we're talking about solanaceous crops, here are some quotes from a 
biography of Count Rumford (born Benjamin Thompson in Massachusetts, 
1771) by Sanborn C Brown.  Count Rumford was an adventurer, a spy, a 
pioneer physicist, developer of the modern fireplace and a pioneer 
nutritionist.  At one stage he was in charge of feeding soldiers 
and poor in Bavaria. For five years he experimented with hundreds of 
people in his Miliatary Workhouse and Poor People's Institute in Munich, 
deciding that soup would be the best form of nutrition, and that a soup 
with barley, peas and potatoes was best.   Because food eaten slowly was 
more satisfying he added stale bread that had been fried crips, forcing 
the soup-eater to chew a considerable length of time.

"He found potatoes to be cheap and filling, but since they were not 
considered fit to eat in Bavaria, for a while he had to smuggle them into 
his kitchen.  All the preparing of potatoes was done in a sealed room 
barred to all but some trusted cooks.  It was not until after the 
potatoes had been used in the soups for some months that he confessed 
their use; thereafter, potatoes became a staple of the Bavarian diet, and 
in central Europe generally."

A typical Rumford recipe was in quantities to feed 1200 people.  But the 
proportions for one portion are: 1 oz pearl barley, 1 oz peas, 3 oz 
potatoes, 1/4 oz bread, 1/4 oz salt, 1/2 oz vinegar, 14 oz water.  
Apparently "Rumford soups" are still found in continental cookbooks.

Jay D Mann  <mannj@southern.co.nz>
Christchurch, New Zealand