Food, wine, fungus, and gamma rays: an ocean of seeming incongruity—and potential

One of my brothers runs an awesome bakery in Scarborough, which offers yeasted and naturally leavened—a.k.a. sourdough—breads of outstanding quality; see Fig. 1.

Fig. 1. Most of these bread products were made using fermentation, either from commercial yeast or other naturally occurring variants. Click on the picture to enlarge.

Both yeasted and sourdough breads are produced using the biological process of fermentation, which is essentially the conversion of sugar to alcohol (CH3CH2OH) and carbon dioxide (CO2). My brother is fond of pointing out the ubiquity of fermentation in the foods of almost all cultures (no pun intended) on earth. Not just bread, but wine, beer, tofu, cheese, kimchi, sauerkraut, miso, yoghurt, tempeh—all of these foods involve fermentation. Fermentation is a metabolic process, almost all done by a species of microscopic yeast fungus called Saccharomyces cerevisiae (Fig. 2).

Fig. 2. Next time you lift a glass of wine, toast this little fungus: it is Saccharomyces cerevisiae, and it is what ferments the grapes. It also ferments the dough in some of the breads in Fig. 1

Almost all alcohol produced in the world is the work of this amazing organism and others similar to it. (There are other ways to make alcohol. I lead a couple of industrial R&D projects that aim to convert CO2 to a number of useful chemicals, including alcohol. But the chemical pathway is much different, and the central reaction is endothermic, meaning it requires heat. Fermentation is exothermic, meaning it gives off heat.)

Important and elemental as fungi in one form or another are to the “fermentation-based” sectors of the world food industry, they are equally important and elemental to other huge areas of the industry. Most plants on earth, including cereal and pulse crops, live in a symbiotic relationship with arbuscular mycorrhizal fungi (literally root fungus). AM fungi are what put water and nutrients to the tops of trees; in return, the trees, via photosynthesis in their leaves, provide sugars to the fungi. Gaze at a forest and you’ll see the visible and familiar parts of that symbiosis. The other part of the symbiosis is invisible. It is made up of vast underground colonies of AM fungi of various species. Scoop up some of the forest mat, and you’ll see it is almost all composed of fine hairs smelling like fungus. That is because they are fungus—they are the hyphae, cylindrical fungal threads that make up a vast branching network associated with the roots of trees and other plants.

Not all fungi are friendly to trees, of course. Some of them eat live trees. In taxonomy, fungi are in their own kingdom. Some species of fungi are as different from others as humans and spiders—both members of the animal kingdom—are from one another. So there is major diversity within the kingdom fungi. Many other fungi eat dead wood and fallen leaves. According to mycologist George Barron, wood-eating fungi return 80 billion tons of carbon, mostly in the form of CO2, to the atmosphere every year. They are carbon recyclers par excellence. No wonder fungi are in their own kingdom.

When you see bracket fungi like the two types in Fig. 3, you’re seeing just the fruiting bodies—the parts of the respective fungi that form the reproductive spores; most of each fungus is inside the tree, digesting it slowly from within. The largest known single organism in the world is a mushroom in eastern Oregon. It feeds on coniferous trees. It was discovered by one Myron Smith, a biologist at Carleton University (my alma mater).

Fig. 3. Different bracket fungi colonizing different trunks of the same birch tree: Fomes fomentarius on the left; who-knows-what on the right. Click on the photo to enlarge.

The importance of fungi in the world’s ecosystems seems pretty clear, but how do they coexist with modern agricultural methods and materials? This is a bit less clear. Some proponents of organic farming point out that one of the benefits of the organic approach is that it does not employ the artificial fertilizers and herbicides/pesticides used in most commercial farming. These chemicals are alleged to be harmful to the AM fungi that live in symbiosis with crop plants. But if that is so, then how would we account for the fact that cereal and pulse crops continue to be produced by industrial, non-organic, methods?

Some organic farming proponents, like the Organic Agriculture Centre of Canada, say that AM fungi might be able to fulfill the role of fertilizers and pesticides/herbicides. The OACC is however more cautious than others in claiming benefits of organic farming. For example, the OACC says

AMF [arbuscular mycorrhizal fungi] might therefore be able to substitute for reduced fertiliser and biocide inputs in organic systems, though there is little evidence for increased yield resulting from high rates of AMF colonisation in organic systems.

Who knows. I am not averse to organic food. I have recently gotten into the fad of cold-pressed seed oils like canola and sunflower; all such products I have purchased so far are labeled as organic. The organic food movement is sometimes conflated with the local food movement, and this is often justified since it’s often the same people extolling both. However, I live in Ottawa Ontario, latitude 45.4214° N. We get a decent summer growing season and a not-so-decent (i.e., non-existent) winter one. Local food is not all that practical in winter.

And artificial fertilizers? They were a major part of the Green Revolution in agriculture that began after the Second World War. The Green Revolution made industrial-scale agriculture possible, and transformed America and Canada into major food exporters. Contrary to the beliefs of many in the organic food movement, this was not a bad thing. Cheap food is good. More people can afford cheap food. And, while I occasionally dabble in food fashions that include organic, cold-pressed seed oils and other things, I am today and have always been a consumer of foods produced on industrial farms. I eat fresh lettuce in the middle of winter, and I eat foods that come from different continents. Avocados and mangos in winter, and all that. I feel pretty healthy. So industrial farms, and food from other continents, can’t be all bad.

I suspect, and this is just a suspicion and not based on science, that a lot of the appeal of organic farming is the same as the appeal of back-to-the-land. I mentioned in “Food, community, and energy” the sheer excitement of being proficient in the outdoors, and knowing what plants you can eat when you’re on your own in the woods—you never know when you’ll need that proficiency.

But I am also an urban dweller, and can do arithmetic. There are billions of humans on the planet, and we are social creatures who like to live close to others of our species. Many already live on the land, and their life is for the most part miserable. For those who have the choice, back-to-the-land is not practical on a full time basis for any more than a very small few. Like it or not, we are inter-dependent. We cannot be independent of each other.

So while I can sympathize with the spirit that draws people to the organic/local food movement, I simply cannot agree with the numerous across-the-board prescriptions against artificial fertilizers, imported food, genetically modified food, and especially—especially—food irradiation.

Food irradiation is the process of exposing food to ionizing radiation, in the form of gamma rays, x-rays, or electron beams. This kills pathogens and bacteria that cause food to rot; it also kills pathogens that make food lethally toxic. Look at irradiation as an additional tool in the food-preservation toolbox, alongside salting, smoking, dehydration, canning, pasteurization, and refrigeration/freezing. Irradiation does not make food radioactive. You can’t “catch” radiation from irradiated food, any more than you can catch skin cancer by eating sun-dried tomatoes. Every national and international body that has looked at the issue has concluded that irradiated food is perfectly safe to eat. These include the Canadian Food Inspection Agency and the World Health Organization.

Of the three types of irradiation energy, gamma rays are the most controversial. The reason for that can be found in the casual misanthropism that afflicts the post-modern affluent West. It’s not really gamma rays per se that bother misanthropic post-moderns. It’s man-made gammas. There are literally thousands of natural sources bombarding earth with gamma rays every second from outer space; obviously, these have nothing to do with humans. The Fermi Large Area Telescope was built and launched to study the more powerful sources. These include pulsars, blazars, supernova remnants, globular clusters, and starburst galaxies. In less than a year of operation (it launched in 2008) Fermi catalogued 1,451 of them. Presumably gamma rays from distant star explosions were bombarding humans when Julius Caesar crossed the Rubicon, just like they are today. Somehow, human civilization has survived this incessant bombardment. Some humans, like us in western Europe and North America, have even prospered.

However, even with all those extraterrestrial gamma sources, here on earth, if we want gamma rays that are controllable and useful, we have to make them ourselves.

Gamma rays are controversial because the only way we can make them is to first make radioisotopes that emit gamma energy as they transmute into other elements. The chief beneficial gamma-emitting isotopes are cobalt-60 and cesium-137. Both are made in nuclear fission reactors: Co-60 by neutron activation of Co-59, and Cs-137 by fission of uranium-235. Canada is the world leader in Co-60 production. Much of it comes from the NRU at Chalk River, and significant amounts are made in CANDU reactors. (Argentina has emerged as the third-largest Co-60 producer after Canada and Russia. The isotope is made in the Embalse CANDU reactor.)

Some people just don’t like fission. But regardless of fission’s unpopularity among certain crowds, many countries practice gamma food irradiation. These countries simply cannot afford to indulge in anti-nuclear superstition—they have hungry mouths to feed every day of the year, and they don’t want significant numbers of their citizens catching food-borne diseases that are easily preventable. In Bangladesh, for example, it is estimated that 18 to 40 percent of harvested fruits and vegetables are lost to pathogens and pests after harvest. A poor country with a population of 142.3 million cannot afford to lose this much food.

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olga lenko aplin
8 years ago

Hi Steve: A very good article, once again you prove that explanation in some detail helps the learning process. You right when you accuse the organic food proponents of belief without much investigation and facts. I do not understand everything you said but about gamma rays, the benefits thereof, and am learning as I go along about symbiosis, the interdependence of living things on each other and have as early as 6 years of age observed the white veins in the ground that you describe as the veins of fungi when I lived on our Ste Sophie farm in Quebec when I watched my dad turning over the soil for seeding. Were there more space here I would love to ask you in person about some things I do not quite understand but soon I will come to Ottawa and we can talk then. Keep well, my dear son, you are doing well. Love you. Mom

8 years ago

A good read. You have opinions that are based on available data, then you have subjective opinions that are based on…your opinions. When you roll them all together it dilutes the purpose of your piece, it waters down your factual information and makes your more strident opinions seem…opinionated.
When you say that “industrial farming and importing foods from other continents can’t be all bad”, I agree with you (they’re only partly bad), but you’re leaving out a pretty big externality that just can’t be dismissed, i.e., the fuel and other resources that it takes to run massive distribution systems like shipping and industrial scale agriculture. Your grasp of the scientific data is impressive, your arguments for large scale anything, less so.

Steve Aplin
8 years ago
Reply to  David Aplin

Dave, thanks — on industrial farming and imported foods I was being polite in saying they can’t be all bad. They’re not bad at all. Dependence on solely local food is a recipe for catastrophe, because there’s always a chance that a harvest will fail in some way. A global food supply insures against that. By necessity that comes with “downsides” like long distance transportation, large-scale farming, etc., and so be it. That’s the price of living on Planet Earth.