Comments on: Preparing to lift potatoes http://stonehead.wordpress.com/2006/09/01/preparing-to-lift-potatoes/ The trials and tribulations of a modern crofter Wed, 23 Jul 2008 05:38:52 +0000 http://wordpress.org/?v=MU By: stonehead http://stonehead.wordpress.com/2006/09/01/preparing-to-lift-potatoes/#comment-183 stonehead Wed, 06 Sep 2006 13:30:10 +0000 https://stonehead.wordpress.com/2006/09/01/preparing-to-lift-potatoes/#comment-183 Rather irritatingly, many of the scientific and agricultural websites differ widely on just how safe green potatoes are. Some don't even mention that the green is an indicator of chlorophyll and not of solanine. But people can start by looking at: http://en.wikipedia.org/wiki/Potato http://www.panhandle.unl.edu/potato/html/greening.htm http://www.panhandle.unl.edu/potato/html/greening_solutions.htm http://www.organicfood.co.uk/inspiration/craig_nightshadefoods.html http://www.pfaf.org/database/plants.php?Solanum+tuberosum But as you say Andrew, it's amazing that supermarkets are allowed to sell potatoes in plastic bags and leave them exposed to light. Rather irritatingly, many of the scientific and agricultural websites differ widely on just how safe green potatoes are. Some don’t even mention that the green is an indicator of chlorophyll and not of solanine.
But people can start by looking at:
http://en.wikipedia.org/wiki/Potato
http://www.panhandle.unl.edu/potato/html/greening.htm
http://www.panhandle.unl.edu/potato/html/greening_solutions.htm
http://www.organicfood.co.uk/inspiration/craig_nightshadefoods.html
http://www.pfaf.org/database/plants.php?Solanum+tuberosum
But as you say Andrew, it’s amazing that supermarkets are allowed to sell potatoes in plastic bags and leave them exposed to light.

]]> By: Andrew Clarke http://stonehead.wordpress.com/2006/09/01/preparing-to-lift-potatoes/#comment-182 Andrew Clarke Wed, 06 Sep 2006 13:03:07 +0000 https://stonehead.wordpress.com/2006/09/01/preparing-to-lift-potatoes/#comment-182 I've always thought that if you cut the green bit off the rest was OK. Apparently not so,according to New Scientist the green itself is of course harmless chlorophyll, but it indicates that an increase in the toxin solanine has been triggered, and this affects the whole potato. The lethal dose is between 3 and 6 milligrams per kilogram of bodyweight or 400-500mg for the avergae person, but even correctly stored spuds can have up to 200 mgs per kilo. On exposure to light this can increase by four times every 24 hours at a temperature of 16'c, and far greater at higher temperatures, even if they potatoes haven't started greening up. The supermarket policy of washing and storing in clear bags is bad news. Potatoes with black streaks from late blight, or ones that have started to sprout should be avoided for the same reason, solanine production will have escalated. Solanine is a cholinesterase inhibitor. Organophosphate insecticides and nerve gasses work in exactly the same way, so we aren't talking mild toxicity here! The solanine is mostly concentrated in the skin, so peeling removes from 30 to 90 % of the toxin. Unfortunately this removes most of the vitamin C as well! On the plus side the toxicity levels for different varieties of potatos vary widely in terms of concentrations and solanine production ability as this was luckily one of the things that evolution is good at and has been bred out of many varieties. The really high levels of solanine also only really affects small immature green potatoes which have low dry solids content. I’ve always thought that if you cut the green bit off the rest was OK. Apparently not so,according to New Scientist the green itself is of course harmless chlorophyll, but it indicates that an increase in the toxin solanine has been triggered, and this affects the whole potato. The lethal dose is between 3 and 6 milligrams per kilogram of bodyweight or 400-500mg for the avergae person, but even correctly stored spuds can have up to 200 mgs per kilo. On exposure to light this can increase by four times every 24 hours at a temperature of 16′c, and far greater at higher temperatures, even if they potatoes haven’t started greening up. The supermarket policy of washing and storing in clear bags is bad news. Potatoes with black streaks from late blight, or ones that have started to sprout should be avoided for the same reason, solanine production will have escalated. Solanine is a cholinesterase inhibitor. Organophosphate insecticides and nerve gasses work in exactly the same way, so we aren’t talking mild toxicity here! The solanine is mostly concentrated in the skin, so peeling removes from 30 to 90 % of the toxin. Unfortunately this removes most of the vitamin C as well!

On the plus side the toxicity levels for different varieties of potatos vary widely in terms of concentrations and solanine production ability as this was luckily one of the things that evolution is good at and has been bred out of many varieties. The really high levels of solanine also only really affects small immature green potatoes which have low dry solids content.

]]> By: Dad http://stonehead.wordpress.com/2006/09/01/preparing-to-lift-potatoes/#comment-181 Dad Mon, 04 Sep 2006 12:39:41 +0000 https://stonehead.wordpress.com/2006/09/01/preparing-to-lift-potatoes/#comment-181 Good advice on the care of your tools mate. All too often they are left to rust etc and then are unserviceable and may pose a safety risk when next they are used. Good luck with your crop of spuds! Hopefully we are just about over the frost season down here, although there is a forecast for a minus temperature in the morning. Good advice on the care of your tools mate. All too often they are left to rust etc and then are unserviceable and may pose a safety risk when next they are used.
Good luck with your crop of spuds!
Hopefully we are just about over the frost season down here, although there is a forecast for a minus temperature in the morning.

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