I was about six the first time I saw a Neptune green edge on my crisps, and I quickly became convinced that was the source of penicillin.
I don’t know where I got the idea, and I don’t believe it anymore (promise). But as an adult, I never stopped to ask myself why the verdigris verges really do appear.
Luckily, it turns out I have Channel 4′s Matt Tebbutt to do that for me. In an episode of Food Unwrapped, the presenter visited Norfolk farmer Toby Mermagen, who only grows spuds for crisps.
And?
And apparently, the “green” potato bits happen in the field, not the factory.
“Potatoes go green due to exposure from light,” Toby explained.
He showed a potato that had gone green at the top end, sharing that “the green part of the potato is chlorophyll.”
“But it contains a chemical called solanine,” he added.
“Solanine is a toxin, and if you eat a lot of it, it will make you feel not very well.”
Solanine (a member of the nightshade family) works as a pest deterrent, which makes sense given it only occurs when the potato’s usually buried body is exposed to the surface of the soil.
It can “cause gastrointestinal and neurological disorders, with symptoms including nausea, diarrhoea, vomiting, hallucinations, paralysis, and even death in severe cases,” ― but only in far greater doses than you’d ever eat.
“You’d have to eat the equivalent of one whole large entirely green potato to feel any ill effects,” the presenter said.
So... it’s OK to eat?
Again, if you somehow get a family pack of only green crisps, don’t chow down on all of them.
But yes, you’re going to be OK after the odd green-laced crisp.
Potatoes are extensively sorted before being washed, sliced, and cooked for crisps, which is probably why you haven’t seen a green crisp for a while.
In Toby’s farm, the unwanted tubers get “sent off for animal feed” (though there are far more undesirable traits than green tips ― the animals aren’t only getting sun-stained spuds).
Who knew?