Gulp: Adventures on the Alimentary Canal (4 page)

But humans, as we are about to see, are not cats.

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A few words on sniffing. Without it (or a Harley), you miss all but the most potent of smells going on around you. Only 5 to 10 percent of air inhaled while breathing normally reaches the olfactory epithelium, at the roof of the nasal cavity.

Olfaction researchers in need of a controlled, consistently sized sniff use an olfactometer to deliver “odorant pulses.” The technique replaces the rather more vigorous “blast olfactometry” as well as the original olfactometer, which connected to a glass and aluminum box called the “camera inodorata.” (“The subject’s head was placed in the box,” wrote the inventor, alarmingly, in 1921.)

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An Internet search on the medical term for nostrils produced this: “Save on Nasal Nares! Free 2-day Shipping with Amazon Prime.” They really are taking over the world.

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“Skunky” is between “rotten egg” and “canned corn” on the Defects Wheel for Beer. (Langstaff designed diagnostic wheels for off-flavors in wine, beer, and olive oil.) In the absence of skunks, a mild rendition of skunkiness is achieved by oxidating beer, that is, exposing it to air, as by spilling it or leaving out half-filled glasses.

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In 2010, inventor George Eapen and snack-food giant Frito-Lay took the comparison beyond the realm of metaphor. They patented a system whereby snack-food bags could be printed with a bar code allowing consumers to retrieve and download a fifteen-second audio clip of a symphonic interlude, with the different instruments representing the various flavor components. Eapen, in his patent, used the example of a salsa-flavored corn chip. “A piano intro begins upon the customer’s perception of the cilantro flavoring. . . . The full band section occurs at approximately the time that the consumer perceives the tomatillo and lime flavors. . . . A second melody section corresponds to the sensation of the heat burn imparted by the Serrano chili.” U.S. Patent No. 7,942,311 includes sheet music for the salsa-flavored chip experience.

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It could be worse. In 1984, goat-milk flavor panelists were enlisted by a team of Pennsylvania ag researchers to sleuth the source of a nasty “goaty” flavor that intermittently fouls goat milk. The main suspect was a noxious odor from the scent glands of amorous male goats. But there was also this: “The buck in rut sprays urine over its chin and neck area.” Five pungent compounds isolated from the urine and scent glands of rutting males were added, one at a time, to samples of pure, sweet goat milk. The panelists rated each sample for “goaty” “rancid,” and “musky-melon” flavors. Simple answers proved elusive. “A thorough investigation of ‘goaty’ flavor,” the researchers concluded, “is beyond the scope of this paper.”

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Probably more. The
Handbook of Fruit and Vegetable Flavors
includes a four-page table of aroma compounds identified in fresh pineapple: 716 chemicals in all.

2

I’ll Have the Putrescine

YOUR PET IS NOT LIKE YOU

D
ESPITE THE CRYPTIC
name and anonymous office-park architecture, the nature of the enterprise that goes on at AFB International is clear the moment you sit down for a meeting. The conference room smells like kibble. One wall of it, entirely glass, looks onto a small-scale kibble extrusion plant where men and women in lab coats and blue sanitary shoe covers tootle here and there pushing metal carts. AFB makes flavor coatings for dry pet foods. To test the coatings, they first need to make small batches of plain kibble and add the coatings. The flavored kibbles are then presented to consumer panels for feedback. The panelists—Spanky, Thomas, Skipper, Porkchop, Rover, Elvis, Sandi, Bela, Yankee, Fergie, Murphy, Limburger, and some three hundred other dogs and cats—reside at AFB’s Palatability Assessment Resource Center (PARC), about an hour’s drive from the company’s suburban St. Louis headquarters.

AFB Vice President Pat Moeller, myself, and a few other staff members are seated around an oval conference table. Moeller is middle-aged, likable, and plain-spoken. He has a small mouth with naturally deep red lips and a pronounced Cupid’s bow, but it would be inaccurate to say he has a feminine appearance. Moeller once consulted for NASA, and he has that look. The fundamental challenge of the pet-food professional, Moeller is saying, is to balance the wants and needs of pets with those of their owners. The two are often at odds.

Dry, cereal-based pet foods caught on during World War II, when tin-rationing put a stop to canning, including the canning of dog food made from horse meat (of which there was an abundance around the time Americans embraced the automobile and began selling their mounts to the knackers). Regardless of what pets made of the change, owners were delighted. Dry pet food was less messy and stinky, and more convenient. As a satisfied Spratt’s Patent Cat Food customer of yesteryear put it, the little biscuits were “both handy and cleanly.”

To meet pets’ nutrition requirements while also giving humans the cheap, handy, cleanly product they demand, mainstream pet-food manufacturers blend animal fats and meals with soy and wheat grains and add vitamins and minerals. This yields a cheap, nutritious pellet that no one wants to eat. Cats and dogs are not grain-eaters by choice, Moeller is saying. “So our task is to find ways to entice them to eat enough for it to be nutritionally sufficient.”

This is where “palatants” enter the scene. AFB designs powdered flavor coatings for the edible extruded shapes. Moeller came to AFB from Frito-Lay, where his job was to design, well, powdered flavor coatings for edible extruded shapes. “There are,” he allows, “a lot of parallels.” A Cheeto without its powdered coating has almost no flavor.
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Likewise, the sauces on processed convenience meals are basically palatants for humans. The cooking process for the chicken in a microwavable entrée imparts a mild to nonexistent flavor. The flavor comes almost entirely from the sauce—by design. Says Moeller, “You want a common base that you can put two or three or more different sauces on and have a full product line.”

Pet foods come in a variety of flavors because that’s what we humans like,
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and we assume our pets like what we like. We have that wrong. “For cats especially,” Moeller says, “change is often more difficult than monotony.”

Nancy Rawson, seated across from me, is AFB’s director of basic research and an expert in animal taste and smell. She volunteers that cats are more or less “monoguesic,” meaning they stick to one food. Outdoor cats tend to be either mousers or birders, not both. But don’t worry, as most of the difference between Tuna Treat and Poultry Platter is in the name and the picture on the label. “They may have more fish meal in one and more poultry meal in another,” says Moeller, “but the flavors may or may not change.”

The extent to which Americans project their own food qualms and biases onto their pets has lately veered off into the absurd. Some of AFB’s clients have begun marketing 100 percent vegetarian kibble for cats. The cat is what’s called a true carnivore; its natural diet contains no plants.

Moeller tilts his head. A slight lift of the eyebrows. The look says, “Whatever the client wants.”

N
ANCY
R
AWSON KNOWS
how to get a cat to finish its vegetables. Pyrophosphates have been described to me as “cat crack.” Coat some kibble with it, and you, the pet-food manufacturer, can make up for a whole host of gustatory shortcomings. Rawson has three kinds of pyrophosphate in her office. They’re in plain brown-glass bottles, vaguely sinister in their anonymity. I asked to try them, which, I think, has won me some points. Sodium acid pyrophosphate, known affectionately as SAPP, is part of the founding patent for AFB, yet almost no one who works for the company has ever asked to taste it. Rawson finds this odd. I do too, though I also accept the possibility that other people would find the two of us odd.

Rawson is dressed today in a floral-print skirt, on the long side, with low-heeled brown boots and a lightweight plum-colored sweater. She is tall and thin, with wide, graceful cheek and jaw bones. She looks at once like someone who could have worked as a runway model and someone who would be mildly put off to hear that. She is brainy and hard working, committed to her job in a way you don’t necessarily expect pet-food people to be. Before she was hired at AFB, she was a nutritionist at Campbell’s Soup Company, and before that, she did research on animal taste and smell at the Monell Chemical Senses Center.

Rawson unscrews the cap of one of the bottles. She pours a finger of clear liquid into a plastic cup. Though pet-food palatants most often take the form of a powder, liquid is better for tasting. To experience taste, the molecules of the tastant—the thing one is tasting—need to dissolve in liquid. Liquid flows into the microscopic canyons of the tongue’s papillae, coming into contact with the “buds” of taste receptor cells that cover them. That’s one reason to be grateful for saliva. Additionally, it explains the appeal of dunking one’s doughnuts.

Taste is a sort of chemical touch. Taste cells are specialized skin cells. If you have hands for picking up foods and putting them into your mouth, it makes sense for taste cells to be on your tongue. But if, like flies, you don’t, it may be more expedient to have them on your feet. “They land on something and go, ‘Oooo, sugar!’’’ Rawson does her best impersonation of a housefly. “And the proboscis automatically comes out to suck the fluids.” Rawson has a colleague who studies crayfish and lobsters, which taste with their antennae. “I was always jealous of people who study lobsters. They examine the antennae, and then they have a lobster dinner.”

The study animal of choice for taste researchers is the catfish,
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simply because it has so many receptors. They are all over its skin. “Catfish are basically swimming tongues,” says Rawson. It is a useful adaptation for a limbless creature that locates food by brushing up against it; many catfish species feed by scavenging debris on the bottom of rivers.

I try to imagine what life would be like if humans tasted things by rubbing them on their skin.
Hey, try this salted caramel gelato, it’s amazing.
Rawson points out that a catfish may not consciously perceive anything when it tastes its food. The catfish neurological system may simply direct the muscles to eat. It seems odd to think of tasting without any perceptive experience, but you may be doing it right now. Humans have taste receptor cells in the gut, the voice box, the upper esophagus, but only the tongue’s receptors report to the brain. “Which is something to be thankful for,” says Danielle Reed, Rawson’s former colleague at Monell. Otherwise you’d be tasting things like bile and pancreatic enzymes. (Intestinal taste receptors are thought to trigger hormonal responses to molecules, such as salt and sugar, and defensive reactions—vomiting, diarrhea—to dangerous bitter items.)

We consider tasting to be a hedonic pursuit, but in much of the animal kingdom, as well as in our own prehistory, the role of taste was more functional than sensual. Taste, like smell, is a doorman for the digestive tract, a chemical scan for possibly dangerous (bitter, sour) elements and desirable (salty, sweet) nutrients. Not long ago, a whale biologist named Phillip Clapham sent me a photograph that illustrates the consequences of life without a doorman. Like most creatures that swallow their food whole, sperm whales have a limited-to-nonexistent sense of taste. The photo is a black-and-white still life of twenty-five objects recovered from sperm whale stomachs. It’s like Jonah set up housekeeping: a pitcher, a cup, a tube of toothpaste, a strainer, a wastebasket, a shoe, a decorative figurine.