("On s’accoutume au poison.")
Victor Hugo (translation W.M. Thomas). 1866. The Toilers of the Sea (Les Travailleurs de la mer), Book IV, Chapter 2. Online: https://www.archive.org/stream/toilersofthesea32338gut/pg32338.txt
There are several programs these days -- "Man vs. Wild," "Alone," "Dual Survival," "Naked and Afraid," to name a few -- in which ill-prepared people try to survive alone in a savage and indifferent wilderness while being filmed. Which does seem just a trifle eccentric, but that's not the point.
One of the most difficult things these folks have to deal with is getting food. Frequently they end up chowing down on things that are vile and disgusting. But I've never seen any program in which someone downed a bushel of Destroying Angel (Amanita bisporigera) mushrooms or an oleander (Nerium oleander) salad. Which is a little surprising -- watching folks vomit and writhe sounds like it might draw big ratings. Apparently these folks, though supposedly ignorant as newborn kittens, never mistake poison hemlock (Conium maculatum) for wild carrots (Daucus carota) despite the fact that even experts have been fooled.
Wild carrot (Daucus carota)
Poison hemlock (Conium maculatum)
Good for them. I for one am certainly not suspiciously wondering if these programs are less "reality" and more "staged." Nope, I just assume these folks are really, really lucky.
The natural world is full of things that people shouldn't eat. Figuring out the difference between "dinner" and "death" was presumably a long and very painful matter of trial and error. What's interesting are all the things that people can't possibly eat -- unless they're very carefully processed.
Acorns (Quercus spp.), bitter almonds (Prunis dulcis amara), bitter yams (Dioscorea bulbifera), cassava (Manihot esculenta), fiddlehead ferns (including Pteridium aquilinum, Matteuccia struthipteris, etc.), pokeweed (Phytolacca americana), and numerous Australian plants -- Moreton Bay chestnut (Castanospermum australe), bunbun (Endiandra insignis), dunu (Prunus turneriana), gulagaa (Ficus copiosa), and gamama (Cycas media) -- are among the many plants that are tasty and nutritious once you get the poison out. And of course, there are lots of things that we eat on a regular basis that, if not actually poisonous, are quite nasty unless they're properly prepared (such as ackee [Blighia sapida], eggplant [Solanum melongena], lupini beans [Lupinus albus or L. mutabilis], olives [Olea europaea], water nut hickory [Carya aquatica], and even soybeans [Glycine max]).
The question is -- how on earth did people figure out that these plants which (in some cases) are deadly could be made into food?
Take, for example, California acorns (various Quercus species, including coast live oak [Q. agrifolia], valley oak [Q. lobata], interior live oak [Q. wislizeni], and the tanbark oak [Notholithocarpus densiflorus]). A mature California oak tree can produce 1,000 pounds (450 kilograms) of acorns a year -- a significant food source (see Moskal 2013). But most acorns are much too bitter to eat (there are rare oaks that produce "sweet" acorns, but that's unusual). So to turn this tempting (but inedible) substance into food takes a few steps:
- Acorns are collected in September and October.
- Fallen acorns are likely to be infested or moldy, so traditionally trees are beaten with poles to knock off mature acorns.
- Take the harvested acorns and put them in water. Discard "floaters."
- Acorns are dried in the shell for up to a year (stirring occasionally to increase air circulation).
- Dried acorns are cracked (using a hammerstone) to extract the nut.
- Nuts are placed in baskets and tossed (winnowed) to separate the nuts from their skins.
- Nuts are ground or pounded into acorn flour.
- The acorn flour is leached in multiple changes of water to remove the bitter tannins. Leaching can be done in a sand pit, in a finely woven basket, or in cloth. The leaching process can take as a little as a few hours to as much as a week.
- Once the flour has been leached of its tannins, the flour is ready for use.
(adapted from Native American Netroots: http://nativeamericannetroots.net/diary/1055 and Moskal 2013: http://baynature.org/article/traditional-modern-methods-acorn-preparation/)
Maggie Howard, also known as Tabuce (1870-1947) seated on ground preparing acorns, surrounded by large baskets of acorns. Yosemite National Park.
Source: https://www.nps.gov/media/photo/view.htm?id=B16B2AB8-155D-4519-3E80C9CF48C04ADD
The process of making cassava (Manihot esculenta) edible is even more difficult -- and the results, if the processing goes wrong, far more serious. Acorns are bitter; cassava is poisonous. As in cyanide. As in deadly.
- Cassava roots are dug up and peeled.
- The peeled roots are steeped in water for 3 days.
- The soaked, peeled roots are dried in the sun (large pieces may be cut up encourage drying).
- The dried roots are pounded to a powder and sifted to remove fibers.
- The fine powder is stored in a bag for 2-3 days.
- Excess water is squeezed out, and the wet flour is dried by roasting.
Cassava roots.
If every step is followed carefully you'll end up with a flour that contains "only" 1.8%-2.4% cyanide. Simpler processing methods exist, but they can leave as much as 33% cyanide in the final product -- which is definitely not healthy. In 2005, for example, 27 children in the Philippines died from eating improperly processed cassava (see Muller-Schwarze 2006 p. 321).
Techniques like this (grinding, leaching) are found everywhere -- in Africa, South America, North America, Asia, and Australia. And they appear to be ancient.
How ancient?
In 2009 Canadian archaeologist Julio Mercader announced the discovery of stone "food processing" tools in Mozambique that were over 100,000 years old and were used to grind wild sorghum (possibly an ancestor of Sorghum bicolor). I can't find any references to stone age leaching -- but interestingly malting sorghum (soaking the grains to start germination) is an important but very tricky process because of the possibility of cyanide production (Lupein 1990). So perhaps this technique goes back much further than I'd imagined.
What I'm left with is a bit of a puzzle. Is this an example of independent innovation, or diffusion? It's certainly possible that people discovered these exceedingly complex ways of turning something plentiful but inedible (or poisonous) into food independently on every continent. It's also possible that these techniques were carried "out of Africa" by our ancestors tens of thousands of years ago.
Food is not always easy. Sometimes it's tricky. Sometimes it's downright ornery. Sometimes it can kill you -- unless you're careful. We are the descendants of clever people, who found ways to survive. That's actually a hopeful thought.
References
Control of Konzo and Kits to Determine Cassava Cyanide and Urinary Thiocyanate. Online: http://biology-assets.anu.edu.au/hosted_sites/CCDN/Deane, Green. 2011. Hickory harvest. Online: http://www.eattheweeds.com/cayra-coffee-or-hickory-java-2/
Deane, Green. 2016. Pokeweed: Prime potherb. Online: http://www.eattheweeds.com/can-be-deadly-but-oh-so-delicious-pokeweed-2/
Hiskey, Daven. 2012. Certain almonds are highly poisonous. Online: http://www.todayifoundout.com/index.php/2012/05/certain-almonds-are-highly-poisonous/
Kallas, John. 2010. Edible Wild Plants. East Layton UT: Gibbs Smith.
Kemp, Kym. 2008. California Buckeye. Online: http://kymkemp.com/2008/11/18/california-buckeye/
Lupein, J.R. 1990. Sorghum and millets in human nutrition. UN Food and Agriculture Organization. Online: http://www.fao.org/docrep/t0818e/t0818e09.htm
Mercader, Julio. 2009. Mozambican grass seed consumption during the Middle Stone Age. Science 18 Dec 2009: Vol. 326, Issue 5960, pp. 1680-1683.
Moskal, Emily. 2013. Traditional and Modern Methods of Acorn Preparation. In BayNature: An Exploration of Nature in the San Francisco Bay Area. Online: http://baynature.org/article/traditional-modern-methods-acorn-preparation/
Muller-Schwarze, Dietland. 2006. Chemical Ecology of Vertebrates. Cambridge University Press, p. 321.
Natural Toxins in Fresh Fruits and Vegetables. 2015. Canadian Food Inspection Agency. Online: http://www.inspection.gc.ca/food/information-for-consumers/fact-sheets-and-infographics/specific-products-and-risks/fruits-and-vegetables/natural-toxins/eng/1332276569292/1332276685336
Ngadjonji Elders. 2004. Ngadjonji History of the Rainforest People. Food Processing: Making Poisonous Foods Safe to Eat. Online: http://earthsci.org/aboriginal/Ngadjonji%20History/food/weapons/Food%20Processing.htm
Perkins, Sharon. What happens if you eat raw soybeans? Online: http://healthyeating.sfgate.com/happens-eat-raw-soybeans-11856.html
Saveur. January 22, 2007. Removing the bitterness from eggplant. Online: http://www.saveur.com/article/Techniques/Removing-the-Bitterness-from-Eggplant
Smart Kitchen. 2016. Bitter almonds. Online: https://www.smartkitchen.com/resources/bitter-almonds
University of Calgary. "Stone age pantry: Archaeologist unearths earliest evidence of modern humans using wild grains and tubers for food." ScienceDaily. ScienceDaily, 18 December 2009. Online: www.sciencedaily.com/releases/2009/12/091217141312.htm
Webster, Judy, Wendy Beck and Bela Ternai. 1984. Toxicity and bitterness in Australian Dioscorea bulbifera L. and Dioscorea hispida Dennst. from Thailand. Journal of Agricultural and Food Chemistry 32(5). Online: https://www.researchgate.net/publication/231548413_Toxicity_and_bitterness_in_Australian_Dioscorea_bulbifera_L_and_Dioscorea_hispida_Dennst_from_Thailand
Wikihow. How to use acorns for food. Online: http://www.wikihow.com/Use-Acorns-for-Food
York, George and Reese Vaughn (revised by Sylvia Yada and Linda Harris). 2007. Olives: Safe methods for home pickling. Division of Agriculture and Natural Resources, University of California Davis, Publication 8267. Online: http://anrcatalog.ucanr.edu/pdf/8267.pdf
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