Who is Making Us Fear Fermented Foods?

A Packet of Sourdough Starter That Gets “Angry”

In the spring of 2007, I received a small envelope containing a sourdough starter. This starter had been born on the Oregon Trail, a relic from the days when America’s early pioneers pushed westward. It looked so unremarkable that I wondered whether I had ordered the wrong thing. Nevertheless, before I went to bed, I mixed it with flour and spring water and set it in a Mason jar. But when I woke, a sticky, frothing batter had overflowed the work surface. Only while clearing up the mess did I realise that this heirloom starter was vastly more active than any store-bought dried yeast.

This starter not only had “personality” but was remarkably “fussy”. If I left it in the fridge unused for too long, it would get “angry”. When I was on a gluten-free diet for a few months and forced it to ferment rice flour and tapioca flour, it got even “angrier”—it would throw a “tantrum” even if I set the thermostat a degree too low in winter. But as soon as spring arrived, it “perked up”. The warm weather set it eagerly digesting the organic rye flour I fed it, and in return it rewarded me with perfect crusty French bread, tender, supple ciabatta, and round, dense sourdough rye loaves.

The success of this starter inspired me to try other fermented products. I sought guidance in Sandor Katz’s The Art of Fermentation, and over time my family of ferments grew to include kefir, kombucha, lacto-fermented cucumbers, beetroot and chillies, tepache (a fermented drink popular in Mexico), cider, and even red wine.

Every evening, I spent time tending my ferments, and this steadied me in an increasingly noisy world. A stable job could collapse along with the financial markets, but I could always look after my ferments; each one was a self-contained world unto itself, and health and a sense of purpose were the rewards I received in return. George Orwell considered tea-drinking a pillar of civilisation. For me, making tea is so that I can brew another batch of kombucha.

I think my motivation for taking up fermentation is not so different from that of the others who keep hens, make pickles, or pursue “self-sufficiency” in the city. I was trying to build a longer-term relationship, not merely to satisfy the present moment. For a very long time—in war or peace, in plenty or in scarcity—people brewed beer, made cheese, baked bread, and cured meat. It was only recently that the art of fermentation came to be seen as mysterious, even dangerous.

Some advised me that fermenting at home was a waste of time. Others warned that I would most likely poison myself. These somewhat dismissive yet unconvincing remarks made me want to ask: why can’t home fermentation offer the same joy of self-sufficiency as baking a pie? I set out to find the answer, and that answer is an important chapter in the history of fermented foods. As it turned out, suspicion of fermented foods was a “special product”, bred of science and market forces intertwined. This “product” proved so influential that it shifted consumer preferences, replacing the richer, more flavourful things we could make ourselves with bland, appetite-destroying mass-produced substitutes. Fermented foods reflect humanity’s relationship with a second kingdom of life—invisible to the naked eye, yet ubiquitous. The history of fermented foods is the history of how we came to recognise that bacteria and fungi are both foe and friend.

Fermented Foods and the Public Health Movement

In August 1922, eight holidaymakers died at a hotel on remote Loch Maree in Scotland, a hotel renowned for its romantic scenery and impeccable management. None of the eight had shown any signs of weakness or illness. On 14 August they had joined a hike organised for them by the hotel. That morning, some had gone fishing, others hillwalking, and afterwards they met up for lunch on the shore of nearby Loch Maree. The lunch consisted of wild duck pâté, ham and ox-tongue sandwiches, accompanied by jam, butter, boiled eggs, scones and cake. Everyone was back at the hotel in time for dinner.

……

The official investigation began. The hotel’s food was sent for bacteriological examination, and the chef was interrogated. On 30 June—six weeks before the tragedy—one of the region’s finest manufacturers had delivered two dozen tins of meat to the hotel. In fact, this manufacturer had observed every precaution at each stage of meat processing. Workers cooked the meat in batches, tinned it, placed the unsealed tins in a retort for sterilisation, then transferred the contents into small glass jars for a second boiling. Before the Loch Maree incident, millions of tins produced by this method had been sold with no reports of poisoning. The chef confirmed that the tins had arrived in perfect condition and that, upon opening, the contents looked and smelled entirely fresh.

Too little pâté remained in the tins for a full analysis. Fortunately, though, investigators excavated another crucial object: a sandwich that the boatman had buried in a flower bed. He had saved it from the earlier hiking picnic to eat for dinner. Having heard that duck pâté might be behind a recent spate of illness, he had buried the sandwich to protect his hens, which could have died had they pecked it up. The sandwich was dug up in time and sent for analysis, which revealed it had been contaminated with toxin—thoroughly, utterly contaminated.

This terrifying toxin baffled everyone. It had survived repeated boiling and sterilisation, let alone burial. In a press release on 25 August, the Scottish Board of Health acknowledged that the poisoning was shrouded in mystery but asked the public to remain calm. Investigators succeeded in isolating a microorganism from the duck pâté. They injected a liquid culture into two mice, and both died; a rabbit, injected in the same way, also died. A bacteriologist noted that the rabbit and the mice had exhibited symptoms of botulism.

Clostridium botulinum is an anaerobic, rod-shaped, spore-releasing bacterium capable of growing in environments where most other bacteria cannot survive. It secretes a potent biotoxin that targets the peripheral nervous system. This toxin is produced only when the bacterium releases its spores. However, these spores are extraordinarily resilient—they survive everywhere from garden soil to salmon gills, and withstand extreme cold, intense heat, and radiation. The first person to identify this bacterium was the Belgian bacteriologist Émile van Ermengem. In 1895, while investigating a series of poisonings linked to sausages and cured meats, he isolated a stubbornly persistent microorganism that remains a leading cause of deadly foodborne illness to this day.

The judicial inquiry concluded that Clostridium botulinum was the sole “culprit” behind the Loch Maree poisoning. This happened to coincide with an era in which nearly every disease was attributed to microorganisms. Microbes and their workings, whether beneficial or harmful, had entered public consciousness through the sanitation movement. The “golden age” of the sanitation movement lasted roughly from the late nineteenth century to the 1930s. It was characterised by a focus on the spread of tuberculosis, typhoid, and other diseases supposedly caused by contaminated water and soil. As knowledge of these pathogens gradually grew, so too did the movement. Before that, such understanding had been confined to laboratories and factories. Ordinary people knew little of the biological processes behind the beer they drank, the cheese they ate, or the unpalatable meat sauce on their plates. They might have had a rudimentary idea—gleaned from everyday observation—that one way of handling food brought pleasure and health, while another brought illness and death. Yet these practices were so deeply woven into traditional customs that no explanation could be offered.

This public health movement disseminated knowledge about microorganisms and their effects, distilling it into a form almost everyone could understand. Domestic-science books and pamphlets issued by publishers brought the “germ theory” of disease as an emerging science into kitchens across the country, encouraging housewives to cook more hygienically. These were certainly good practices. And yet the movement also became a classic tyranny of good intentions, lending an air of invisible danger to the most ordinary domestic tasks—so apt a fit for the proverb “a small viper carries deadly venom”.

For centuries, home-made pickles, wine, and buttermilk had seldom gone wrong. But now people knew that microorganisms lurked everywhere, silently waiting for the smallest lapse in cleanliness. Because they were both undetectable and ever-present, the anxiety provoked by the risk of microbial contamination was enough to drive housewives towards foods that had once been made at home but were now produced in factories and stocked in shops.

New methods of fermenting food once coexisted with the old. The most advanced modern breweries bottled their beers, and factory-made cheeses appeared on shelves alongside home-made pickles and loaves. But as history rolled from the nineteenth into the twentieth century, railways brought new kinds of food to market, and radio broadcasts drew attention to them. The big companies that produced them managed to persuade the public that only they were reliable, clean, and wholesome. Imitating Britain’s Sale of Food and Drugs Act of 1875 and Margarine Act of 1887, the US Congress passed the Pure Food and Drugs Act in 1906, further bolstering this compelling campaign. Only well-capitalised firms could invest in the equipment the new standards demanded, thereby obtaining the government-approved certification consumers now sought. The cost of achieving that certification soared so high that smaller manufacturers could only watch their customer base shrink and, soon enough, go bankrupt.

Success made the big corporations hungry for more, and they placed even greater emphasis on providing only wholesome food. Domino Sugar claimed that machine-processed food was cleaner and therefore safer than anything made by hand; Gold Medal Flour boasted that their product had never been touched by a mill worker; Kellogg’s advertised that their cereal boxes were sealed against contamination; and Heinz invited the public into designated areas of its factories to watch women in pristine white uniforms packing the company’s pickles.

Big companies’ advertising campaigns were built on such stunts, often escalating from past showmanship to outright brazenness. To gain an edge in the domestic market, the American Sugar Company published advertisements showing magnified images of harmless but terrifying-looking microorganisms in brown sugar, presented as proof that eating raw sugar was dangerous. The campaign was an overwhelming success: even the best-selling Boston Cooking School Cookbook warned readers to stay away from brown sugar, claiming “tiny insects” lurked within it.

The breakfast cereal and biscuit industries began to follow suit. Manufacturers claimed that only pre-packaged cereal was guaranteed free of bacteria. A bacon-and-egg breakfast, a loaf of yeast-raised bread—any of these could make you ill. “Toasted corn flakes”, produced to the highest hygiene standards, were presented as by far the safer, healthier choice. For biscuit makers, the “enemy” was a fixture of the village shop—the biscuit barrel. These barrels were breeding grounds for bacteria: biscuits arrived from wholesalers, were tipped into barrels that might not be hygienic, and were then fished out by hands that might not be hygienic either. Nabisco offered an alternative: individually wrapped biscuits, neatly presented, apparently untouched by human hands.

For these mass-produced foods, a spotless appearance was the only ambition (many large food factories erected idealised model production lines for curious visitors, while actual production took place in less tidy quarters). Beyond that, mass-produced food was dull, uniform, and devoid of the local character of traditional fare. “I hear the American kitchen is dreadful,” Tsar Nicholas II remarked to a subject of his—an opera singer who had just returned from a visit to the United States—”all the food is mass-produced, with no distinctive taste or flavour whatsoever.”

The same judgment applied to mass-produced foods in Europe. In industrial cities such as Manchester, time-pressed workers abandoned watercress, fish, and other traditional foods in favour of tinned beef and Bird’s Custard, because processed food was easier to eat when you had only a few hours of spare time. In the end, the time workers saved was lost again: life expectancy shortened, and many fell victim to scurvy, tooth decay, and other degenerative diseases.

In Switzerland, the food-industry pioneer Julius Maggi persuaded housewives to accept his improved stock cubes. Despite lacking the flavour and nutrition of a home-made stock, they held a powerful appeal for modern women working outside the home. The stock cubes were a resounding success, and in 1897 Maggi founded the company that bears his name in Germany. Convenience triumphed over taste, and the uninterrupted, fixed rhythm of factory production gradually reshaped people’s daily habits. The time spent cooking could not be spent earning a wage. Moreover, industrial production made food cheaper. The industrialist Auguste Cortese, a former chef to Umberto I of Italy, declared in the 1880s: “Every day, the great factories will offer delicious, freshly made and cooked food at extraordinarily low prices. This will be the dawn of a new era!”

This was the dawn of a new century. The sanitation movement marked a turning point in food production and preservation, for better or for worse. It taught ordinary people simple methods for warding off dreadful diseases. Though they grew healthier and less prone to illness, they also surrendered considerable autonomy in domestic and culinary matters to government and big business. In the realm of humanity’s relationship with microorganisms, the sanitation movement’s predictions and prescriptions were absolute and singular, disregarding individual differences or traditional beliefs.

In traditional practice, those somewhat rough, culturally specific pieces of advice inspired a kind of creativity in those who followed them, yet they have been supplanted by a rigid regime of rules founded on fear (which is why knowledge about avoiding a cold is more commonplace today than knowledge about baking sourdough or pickling carrots). This fear, as the Loch Maree incident demonstrated, was not without justification. Whether bacteria, yeast, or mould, these tiny, double-edged creatures could bring disease just as readily as health. The contemporary French sociologist Bruno Latour writes in The Pasteurization of France: ‘Society is not composed of humans alone; microorganisms intervene and act everywhere.’ So who can discern the purposes of these hidden ‘agents’?

The Duality of Microorganisms

Before the modern era, no one could have known. To understand the duality of microorganisms, we need to learn something about their biology. Microorganisms are living things too small to be seen with the naked eye. In fact, a single pinhead can hold millions—even more—of microorganisms. Their existence stretches back through ages of antiquity. Microorganisms spent hundreds of millions of years waiting for the humans they would accompany, and once humanity is gone, they will very likely endure for another few hundred million years. They came into being about four billion years ago. The Earth of that era was no friendly, gentle world we call home, but a planet hammered by comets, meteors, and solar radiation. On top of these onslaughts, the moon orbited far closer to Earth than it does today, and its gravitational pull whipped up violent tidal surges. Beneath the turbulent seas, hydrothermal vents released tremendous energy. Around these vents lay deposits of sediment rich in the substances essential to life. As the pioneering British science fiction writer H. G. Wells wrote, this was ‘a faint glimmer, not yet kindled, amid the vastness of the void.’

Yet, not yet kindled, life nonetheless took root in the form of primitive cells. Even billions of years ago, as the Earth cooled from its blazing early state, life continued to flourish and diversify. It evolved into two sharply distinct single-celled forms: bacteria and archaea. Bacteria have cell walls but lack a true nucleus. Archaea are similar in size to bacteria and equally simple in structure, yet, unlike bacteria, they possess more complex genomic structures and metabolic pathways. Although both bacteria and archaea can harness solar energy, the latter favour less hospitable environments. Beyond these differences, the two groups share certain close affinities.

According to the mainstream endosymbiotic theory, at some point archaea absorbed bacteria without destroying them; the two fused to form eukaryotes—cells and organisms with a clearly defined nucleus containing DNA arranged as chromosomes (we humans are eukaryotes). Thanks to the extra energy provided by the bacteria, this new symbiotic form could grow larger, accumulate more genes, and become more complex. The waste product generated by these evolved strains—oxygen—then created the conditions for the diversification of life.

Microorganisms are everywhere, playing a role in every biological process. They maintain the world’s many ecosystems and contribute to the health of the creatures living within them. They break down dead organisms and sustain the living. Yet, when conditions favour them, they can also bring disease, famine, and death.

Approximately 39 trillion microorganisms live inside our bodies, yet we understand the roles and functions of only a small fraction of them. We know that many microorganisms strengthen the immune system, regulate blood sugar, improve digestion, and make other beneficial contributions to our health and well-being. As far as we are concerned, humanity has learned to harness microorganisms to increase our food supply, making it more nutritious and more delicious. We tame microorganisms much as we tame cattle and sheep, in order to feed ourselves.

But what are we to them? That unsettling question remains unanswered, and the motives of these invisible life forms are still unknown. In 1891, Professor Percy Frankland observed that they ‘swarm in extraordinary numbers in every environment around us, possessed of remarkable potential for both good and evil—sometimes acting as our friends and faithful servants, performing the tasks set for them without complaint, and at other times defying us like irreconcilable enemies, scorning our power and our wit’. We expend as much energy battling the microorganisms that cause disease and death and ruin our labours as we do cultivating those that bring health and happiness. We strive to tame microorganisms, lest we become their “colonies”.

Happily, as the English novelist Thomas Hardy wrote, these relentless struggles have produced a “truly wonderful history”, along with quite a number of delicious foods. But before we dig into those, we should think about drinks first, for a considerable number of early fermented products took the form of alcoholic beverages.