‘Adulterations Detected:’ on the human impulse to prettify our food with poison

In the summer of 1848, two caterers were convicted of manslaughter.

On an afternoon in early June, the people of Northampton gathered in Temperance Hall for what should have been a rather tame ordination celebration. The caterers placed a blancmange on the table. One guest was especially smitten with the quivering custard pudding, all dressed up with decorative leaves. He spooned down half a pound before going home, where he went to bed at 8 p.m., exhausted by his feasting. By 5 a.m., he was dead.

The caterers hadn’t meant to poison anyone. They had followed their usual recipe. As always, they had dyed the leaves with Schweinfurt green, only this time in “a somewhat larger portion than usual to give a more beautiful color.” 

“People think brightly colored food tastes better,” says molecular biologist and nutritionist Marion Nestle. “When given two identical foods, one brightly colored and the other not, they perceive the brightly colored one as significantly better.”

But prettying up food for palatability can come at a cost. History shows us just how steep.

Arsenic, to taste

England’s population swelled in the 19th century, ratcheting up demand for cheap food. And cheapness encouraged trickery. Milk was watered down until it turned gray-blue. Chalk was ground into flour. Cider was bottled as expensive French wine. But the greater the dilution, the duller the food. To restore the food’s natural saturation, or sometimes even surpass it, producers reached for chemical colors. The Northampton blancmange’s lethal green, for example, was made from copper and arsenic.

Contemporaries knew it was dangerous. The satirical magazine Punch joked that grocers could sell tea to kill rats or chocolate to poison beetles. In his 1857 text Adulterations Detected, chemist Arthur Hill Hassall warned Parliament and the public that in a single meal, a diner might eat red lead in curry, copper in pickles and, for dessert, candies dyed with “no telling what number of poisonous pigments.” Yet the dyes continued to sell. Arsenic greens, lead reds, and mercury yellows made their way onto the plates of both rich and poor. 

Chemist Friedrich Accum described street vendors tempting children with sugar plums dyed with a host of poisons. In his 1820 treatise against chemical additives, he wrote, “The man who robs a fellow subject of a few shillings on the high-way is sentenced to death, while he who distributes a slow poison to a whole community escapes punishment.” 

The most infamous color of all was Scheele’s green, the predecessor of the blancmange pigment. Invented in 1775 by Swedish chemist Carl Wilhelm Scheele, it was breathtakingly bright, more vivid than any dye Victorians had seen. Less than a year after he created it, though, Scheele had doubts. He wrote to a colleague that the chemical might be dangerous and people ought to be warned. But although people knew how toxic arsenic was, the prevailing belief was that small doses were harmless, even medicinal. That faith proved fatal. Scheele himself died at 43, poisoned by years of exposure to his own discoveries. His green lived on to claim many more victims. It was so notorious it may be why we still visualize poison as green.

‘Butter yellow’ greases margarine margins

The sale of arsenic was regulated in 1851, but by the late 19th century, the aesthetics arms race had shifted to margarine. Invented in 1869 as a cheap substitute for butter, margarine was made from beef fat and milk, rendering it grayish white. It looked pallid next to butter’s warm yellow, and producers quickly realized that without color, margarine would never sell. Annatto, a harmless seed extract, could supply the hue, but synthetic coal-tar dyes were cheaper. The most common of these tar dyes was “butter yellow,” a compound that gave margarine the sunny glow of farm-churned butter while generating cancer-inducing mutations in the human body. 

Yellow margarine was a hit. In the United States, it sold so much that dairy lobbies were worried. Legislature in some states mandated that all margarine be dyed pink, a visible badge separating buyers who could afford butter from those who couldn’t. But butter was often tinted too, sometimes with dyes no safer than margarine’s. Food of this era was locked in a beauty pageant, one that hasn’t entirely stopped.

Still dying for dye

Modern psychology and nutrition science has confirmed how powerfully the eye governs the tongue. In one experiment, orange coloring made nearly a fifth of participants believe that a cherry-flavored solution tasted of orange. When the same liquid was turned green, a quarter of tasters swore they tasted lime. Color is, in itself, a seasoning without a flavor. And it’s capital. 

“In the US, they’ve done experiments taking out the dyes (Mars, Trix), but soon put them back when sales declined,” Nestle explains.  

Even now, appearance can win over safety. In 2014, Taiwanese authorities discovered that dried tofu products like dougan had been adulterated with butter yellow. The practice seems to endure because the rewards are immediate while the consequences are distant.

The story of the Northampton blancmange is a reminder that design requires guardrails. Without them, producers might just be tempted to add “a somewhat larger portion than usual to give a more beautiful color.”