Paul Hetzler
The Advocate
As a longtime gardener who likes to make healthy and eye-pleasing meals, I enjoy the colourful veggies that have come on the market in the past decade or so. Even apartment-dwellers with space on a balcony or patio for a few containers can now grow red lettuce, orange cauliflower, pink potatoes, golden beets, black tomatoes and purple carrots. These and other rainbow-hued produce are also available at farmers’ markets and in large grocery stores.
But as Doctor Suess noted in his children’s book Green Eggs and Ham, pigmented foods need the right context or people are likely to balk.
While bright colours are charming in a stir-fry or omelette, purple milk and orange meatloaf don’t have the same appeal.
Aside from blueberries, blue foods are a tough sell for me. Only chicken cordon bleu with a glass of Blue Nun sound enticing, and neither of those is actually blue. In particular, I find the phrase “blue fungus” to be an appetite suppressant. And yet, an edible blue mushroom called Lactarius indigo may provide us with a powerful means of battling the climate crisis, as well as helping to alleviate food and water insecurity.
Also known as the indigo milk-cap or blue milk-mushroom, L. indigo is native to forested regions of eastern North America, East Asia, Central America and parts of Western Europe. This mushroom’s most unusual feature is that when cut or broken, it oozes a milky blue latex. Once exposed to the air, its gooey blue “blood” slowly turns green. All of which screams “yum,” of course.
The indigo milk-cap is one of many species of mycorrhizal fungi that form symbiotic relationships with tree roots. Though mycorrhizae take small amounts of sugars from roots, they greatly boost their efficiency, allowing trees to absorb water and nutrients more readily. In this win-win scenario, L. indigo lives off trees while making them healthier and faster-growing overall.
Eaten fresh, indigo milk-caps are said to have the crispness of an apple. Their flavour varies from site to site, but is usually described as mild, and when cooked tastes similar to a portobello. Indigo milk-caps and other mushrooms can also be processed to mimic seafood, meat and cheese products, as well as used to make soy sauce, or even fermented into wine and beer.
In a study published in February 2022, researchers from the University of Stirling in England, and El Colegio de la Frontera Sur San Cristóbal de las Casas in Chiapas, Mexico, showed that the amount of protein found in blue milk mushrooms on a hectare of forest exceeds that of beef cattle raised on a hectare of pasture. Not only that, the mushrooms can be harvested year after year with no inputs.
However, the real beauty of these mushrooms is that forests that are either inoculated with L. indigo spores, or already have existing populations of the fungus, remain intact. For a variety of reasons, it takes roughly a century for a tree seedling to become an effective carbon store. These “shroom-forests” will continue to grow and sequester carbon, thus helping to mitigate climate change, and all the while can still be used for recreation or hunting. Land managers can keep harvesting a percentage of mature trees on the same prudent schedule as before, without compromising forest health or affecting the L. indigo mushroom crop.
Worldwide, forests are being clear-cut at the alarming rate of about 24.7 million acres a year. In South America, around 85 per cent of deforestation is for the creation of pasture for beef cattle, and to grow other kinds of animal feeds. Worldwide, beef cattle burp enough methane each year to equal more than 3 billion tons of carbon dioxide, on top of the many other types of greenhouse-gas emissions caused by deforestation.
According to the United Nations Food and Agriculture Organization (FAO), “When sustainably managed, forests contribute significantly to reducing soil erosion….” The FAO also says forests help conserve water, protect fisheries, safeguard biodiversity and provide us with cultural and spiritual benefits.
The FAO reports that close to 80 per cent of humanity faces water insecurity. With about three-quarters of the world’s fresh water originating from forested watersheds, it’s more important than ever to leave forests in place. Harvesting blue milk-mushrooms on a portion of the woodlands now slated for conversion to beef pasture and planting new forests with trees inoculated with L. indigo are great ideas, but will require buy-in from landowners, and most likely some kind of government incentives as well.
Public acceptance of foods based on L. indigo will also be crucial. In 1960, Dr. Seuss got his characters to accept green eggs and ham by pestering them with an intrusive stalker. These days, such antics would get Sam-I-Am taken away in handcuffs. But with soaring food prices giving everyone the “food blues,” perhaps a good PR campaign can sell the world blue veggie-burgers and imitation cheese.
As severe weather events become increasingly common, as well as more costly and destructive, consumer demand is likely to shift away from carbon-intensive food sources to some degree. Growing blue milk-mushrooms in your woodlot isn’t for every landowner. But it’s important to be aware of the many agro-forestry options that could give smaller diversified farms a leg-up as consumer tastes change going forward.