Gulp: Adventures on the Alimentary Canal (14 page)

*
But not its bubbles. Frothiness is a hallmark of proteins in general; saliva has more than a thousand kinds. Proteins bind to air. When you whip cream or beat eggs, you are exposing maximum numbers of proteins to air, which is then pulled into the liquid, forming bubbles. That disturbing white foam on the cheeks and necks of racehorses is saliva whisked by the bit. (The whisking of semen is complicated by its coagulating factor. Should you wish to know more, I direct you to the mucilaginous strands of the World Wide Web.)

*
Literally. The coating is real silver. That’s why the label says “For Decorative Use Only.” Like everyone else, environmental lawyer Mark Pollock didn’t realize you weren’t supposed to eat them. In 2005, Pollock sued PastryWiz, Martha Stewart Living Omnimedia, Dean & DeLuca, and a half-dozen other purveyors of silver dragees, as they are known in the business. Pollock succeeded in getting the product off store shelves in California. Fear not, holiday bakers, silver dragees are available in abundance from online sellers, along with gold dragees, mini dragees, multicolored pastel dragees. And dragee tweezers. (With cupped ends “to easily grab individual dragees.”)

†
As does this: Claims made by makers of mouthwash to kill 99 percent of oral bacteria are misleading. Silletti says half the species can’t be cultured in a lab; they grow only in the mouth. Or
on other bacteria.
“When you ask the companies for claim support, they will show you the statistics for the kinds they can culture.” How many others there are, or what mouthwash does to them, is unknown.

*
In 1973, inquisitive cold researchers from the University of Virginia School of Medicine investigated “the frequency of exposure of nasal . . . mucosa to contact with the finger under natural conditions”—plainly said, how frequently people pick their nose. Under the guise of jotting notes, an observer sat at the front of a hospital ampitheater during grand rounds. Over the course of seven 30-to 50-minute observation periods, a group of 124 physicians and medical students picked their collective noses twenty-nine times. Adult Sunday school students were observed to pick at a slightly lower rate, not because religious people have better manners than medical personnel, but, the researchers speculated, because their chairs were arranged in a circle. In a separate phase of the study, the researchers contaminated the picking finger of seven subjects with cold virus particles and then had them pick their nose. Two of seven came down with colds. In case you needed a reason to stop picking your nose.

*
Fear the fight bite: it can cause septic arthritis. In one study, 18 of 100 cases ended in amputation of a finger. Hopefully the middle one. In the aggressive patient, a missing middle finger may be good preventive medicine.

*
The zookeepers, however, got very, very quiet. “So maybe,” said Bronstein in an e-mail, “the dragon spit some of its quietness spray on them.” I am almost 100 percent sure that that is not a reference to Sharon Stone.

†
The term
quack
derives from
quacksalber
, German for “quicksilver” (mercury’s nickname). It took a while for medicine to see the light. As late as 1899, the
Merck Manual
suggests mercury as an antisyphilitic, to “produce salivation.” Syphilitics weren’t the only ones salivating over mercury. Merck was, at the time, reaping profits from eighteen different “medicinal” mercuries.

*
Not to be confused with the Nutter D. Marvel Museum of horsedrawn carriages or the Butter Museum, a working farm that “showcases all things butter, from various styles of butter dishes to the history of butter through the ages,” perhaps turning away briefly during butter’s history-making 1972 role in
Last Tango in Paris
.

7

A Bolus of Cherries

LIFE AT THE ORAL PROCESSING LAB

W
HEN
I
TOLD
people I was traveling to Food Valley, I described it as the Silicon Valley of eating: fifteen thousand scientists dedicated to improving or, depending on your sentiments about processed food, compromising the quality of our meals. At the time I made the Silicon Valley comparison, I did not expect to be served actual silicone. But here it is, a bowl of rubbery white cubes the size of salad croutons. Andries van der Bilt brought them from his lab in the brusquely named Department of Head and Neck, at the nearby University Medical Center Utrecht.

“You chew them,” he says.

Van der Bilt has studied chewing for twenty-five years. If a man can be said to resemble a tooth, van der Bilt is a lower incisor, long and bony with a squared-off head and a rigid, straight-backed way of sitting. It’s between meals now in the camera-rigged Restaurant of the Future. The serving line is unstaffed, and the cash registers are locked. Outside the plate-glass windows, it’s snowing again. The Dutch pedal along on their bicycles, seeming daft, or photoshopped.

The cubes are made of a trademarked product called Comfort Putty, more typically used in its unhardened form for taking dental impressions. Van der Bilt isn’t a dentist, however. He is an oral physiologist. He uses the cubes to quantify “masticatory performance”—how effectively a person chews. Research subjects chew a cube fifteen times and then return it in its new, un-cube-like state to van der Bilt, who pushes it through a set of sieves to see how many bits are fine enough to pass through.

I take a cube from the bowl. Van der Bilt, the cameras, and emotion-recognition software called Noldus FaceReader watch me chew. By tracking facial movements, the software can tell if customers are happy, sad, scared, disgusted, surprised, or angry about their meal selections. FaceReader may need to add a special emotion for people who have chosen to have the Comfort Putty. If you ever, as a child, chewed on a whimsical pencil eraser in the shape of an animal, say, or a piece of fruit, then you have tasted this dish.

“I’m sorry.” Van der Bilt winces. “It’s quite old.” As though fresh silicone might be better.

The way you chew is as unique and consistent as the way you walk or fold your shirts. There are fast chewers and slow chewers, long chewers and short chewers, right-chewed people and left-chewed people. Some of us chew straight up and down, and others chew side to side like cows. Van der Bilt told me about a study in which eighty-seven people came into a lab and chewed an identical amount of shelled peanuts. Though all had a full complement of healthy teeth, the number of chews ranged from 17 to 110. In another project, subjects chewed seven foods of widely varying textures. The best predictor of how long they chewed before swallowing wasn’t any particular attribute of the food. The best predictor was simply who’s chewing. Your oral processing habits are a physiological fingerprint. As with the finger kind, most of us have no idea what ours look like.
^*
We couldn’t pick our own chewing mouths out of a lineup, although it would be interesting to try.

Van der Bilt studies the neuromuscular elements of chewing. You often hear about the impressive power of the jaw muscles. In terms of pressure per single burst of activity, these are the strongest muscles we have. But it is not the jaw’s power to destroy that fascinates van der Bilt; it is its nuanced ability to protect. Think of a peanut between two molars, about to be crushed. At the precise millisecond the nut succumbs, the jaw muscles sense the yielding and reflexively let up. Without that reflex, the molars would continue to hurtle recklessly toward one another, now with no intact nut between. To keep your he-man jaw muscles from smashing your precious teeth, the only set you have, the body evolved an automated braking system faster and more sophisticated than anything on a Lexus. The jaw is ever vigilant. It knows its own strength. The faster and more recklessly you close your mouth, the less force the muscles are willing to apply—without your giving it a conscious thought.

You can witness the protective cutout reflex by hooking up a person’s jaw muscles to an electromyograph. The instant something hard gives way, the readout of electrical activity goes briefly flat. “The silent period, they call it,” van der Bilt says. It seems like a term kindergarten teachers might use, or people at a Quaker meeting. All these years, I’ve had it backward. Teeth and jaws are impressive not for their strength but for their sensitivity. Chew on this: Human teeth can detect a grain of sand or grit ten microns in diameter. A micron is 1/25,000 of an inch. If you shrank a Coke can until it was the diameter of a human hair, the letter
O
in the product name would be about ten microns across. “If there’s some earth in your salad, for instance, you notice immediately. It warns you for the wrong things.” Van der Bilt did the experiment himself. “We took some
vla . . .”
Custard! In the Netherlands,
vla
is never far from where you are. “We put some plastic grains of various sizes in it . . .”

Van der Bilt stops himself. “I don’t know if you want to hear these things.” He has a tentative, apologetic manner of speaking, like a man accustomed to feeling that his audience, at any moment, is about to make an excuse and get up to go. Earlier he told me that his unit at Utrecht is slated to close when he retires, in a year. “There isn’t,” he said, “enough interest.”

I think it may be something else.

T
HE STUDY OF
oral processing is not just about teeth. It’s about the entire “oral device”: teeth, tongue, lips, cheeks, saliva, all working together toward a singular unpicturesque goal: bolus formation. The word
bolus
has many applications, but we are speaking of this one: a mass of chewed, saliva-moistened food particles. Food that is in—as one researcher put it, sounding like a license plate—“the swallowable state.”
^*

I don’t think the scientists are uninterested. I think they may be disgusted. This is a job where on any given day, you may find yourself documenting “intraoral bolus rolling” or shooting magnified close-ups of “retained custard” with the Wageningen University tongue-camera. Should you need to employ, say, the Lucas formula for bolus cohesiveness, you will need to figure out the viscosity and surface tension of the moistening saliva as well as the average radius of the chewed food particles and the average distance between them. To do that, you’ll need a bolus. You’ll need to stop your subject on the brink of swallowing and have him, like a Siamese with a hairball, relinquish the mass. If the bolus in question is a semisolid—yogurt and
vla
are not chewed, but they are “orally manipulated” and mixed with saliva—the work is yet less beautiful. As evidenced by this caption in a textbook chapter by my host René de Wijk: “Figure 2.2. Photographs of spat-out custard to which a . . . drop of black dye has been added.”

Humans, even physiologists, don’t like to think about food once they’ve begun to process it. The same chanterelle and Gorgonzola galette that had the guests swooning is, after two seconds in the mouth, an object of universal revulsion. No one knew this more intimately than Tom Little, an Irish American laborer who ate his meals by chewing food and spitting it into a funnel that fed into his stomach. When he was nine years old, in 1895, Tom swallowed a draught of clam chowder without letting it cool. The burn healed with strictures that fused the walls of his esophagus. Surgeons created a fistulous opening to his stomach so he could eat—or “feed,” as Tom now referred to the act of taking in sustenance. It was an undiminishing source of embarrassment. (Interestingly, his doctor noted in a book about the case, Tom “blushed both in his face and his gastric mucosa.”) He told no one, and took his meals alone or with his mother. When he finally married, it was to an older woman for whom he felt little attraction. He chose her, he told his doctor, because “she doesn’t mind the way I feed.”