Is Gulf Seafood Safe: Confessions of a Shrimp Sniffer

The first line of defense against oil-tainted seafood: an old-fashioned smell test. Fresh from government sniffing school, Bill Mahan describes the odd odors protecting the public health.

Bill Haber / AP Photo

The oil pouring out of the Deepwater Horizon well, decimating wildlife, ecology, and income alike has an incongruously sweet, fresh odor. I know: Over two days, recently, I did little more than smell it.

My nose, and others like it, turns out to be the best line of defense we have against the possibility of contaminated seafood from the Gulf, given the current impracticality and expense of laboratory tests.

Using portable gas chromatographs, a.k.a. a person's nose, is a faster, more economical way to screen the seafood. Which is how I found myself among the first 20 recruits last month being trained by the National Oceanic and Atmospheric Administration to inspect various fish and shellfish for levels of petroleum.

Eventually they gave us actual oil from the Deepwater Horizon spill. It has a unique odor, sweet and fresh—a sweetness that car oil doesn't have.

For two days, five professional sensory evaluators, at NOAA's seafood inspection lab in Pascagoula, Mississippi, in collaboration with the FDA and the International Food Protection Training Institute, taught us the fine art of smelling shrimp. My job, as a food researcher at the University of Florida, made me a logical candidate—NOAA, which pays for the boot camp, has focused specifically on getting testers trained in the five Gulf states. (None from my training class has actually been called into the "field" yet.)

The teachers started by putting us on a pretty strict, very bland diet designed to keep our noses pristine. No spicy food, no orange juice. The instructors then presented a basic introduction to the sensory evaluation of food. We were given dark vials filled with relatively common items—things like cucumber, yeast, and rice—to see if we could identify what they were as well as practice attaching descriptive words to the smells we were experiencing.

They also gave us a couple of little tests. The key to effective smelling, we were told, was multi-sensory coordination: vision, taste and smell all work together. As if to prove the point, we were given glasses of seltzer water that had been tainted yellow with food coloring and was flavored with a very common fruit juice. They had us smell it first, and I remember thinking "Oh, yes, I know that odor!" but I couldn't put a word to it. People around me were saying, "I know that smell," but no one was able to identify it. They said it was safe to take a sip and I kept thinking I knew what it was. My mind was racing, trying to come up with the identity. It wasn't banana, not pineapple, not lemon. It was enough to drive you nuts. It was strawberry. The yellow color had us all messed up; not one person guessed it.

In another, we were given a cup of granular material and told to put it on our tongues, with our eyes closed and noses plugged. It had the texture of sugar crystals, but I didn't taste any sweetness. I opened my eyes and exhaled. Wow! Immediately, I knew it was cinnamon sugar. Not one person in the room had a clue it was cinnamon, because without the odor of cinnamon, it's impossible to sense.

Next there was a series of labeled products, mostly oils that they wanted us to smell and describe. There were two types of bunker oil, creosote, used motor oil, some non-oil products—eventually they gave us actual oil from the Deepwater Horizon spill. It has a unique odor, sweet and fresh—a sweetness that car oil doesn't have.

Complete coverage of the Gulf oil spillAfter we familiarized ourselves with the smells of different oils, we moved to a lab with artificially contaminated oysters, red snapper and brown shrimp at separate stations in concentrations of 10, 20 and 40 parts per million, as well as uncontaminated controls.

The instructors explained the critical thing was to be able to detect relative strength of the odor, but they weren't sure we'd be able to detect the oil in the least saturated samples. Part of this exercise was to give them the opportunity to assess our abilities. Again, we recorded any observations or sensations that we had while we smelled the samples.

To cleanse our palettes, we sniffed chopped watermelon, cucumber and canned corn held in Pyrex containers throughout the lab. I would compare it to wine tasting—you take a sip and cleanse your palette. I particularly liked the watermelon followed by the corn. The instructors also suggested burying our noses in our shirts or in the crook of our elbows to recalibrate your sense of smell to your own odor—a trick of the trade. (After boot camp, I compared notes with a man in the perfume business, who told me about his "library of scents," a reference to identify specific oils/fragrances.)

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When I did the shrimp infused with 10 parts per million, I couldn't detect a clear oil odor, but I got a burning sensation in my sinuses that I didn't experience with the control samples. One inspector from Mississippi had a rather sensitive gag reflex: She could smell the control samples, but if a sample was contaminated with oil, it was gag, gag, gag—a perfect example of how each person's sensory perception reacts in different ways.

For the testing phase, we each went into the lab to face eight numbered, covered Plexiglas bowls, which held oysters, shrimp, and fish with different concentrations of oil and control samples that we had to identify. After each test we'd take a break and then go back in to test eight more samples. We repeated this until each of us smell-tested 16 samples of each type of seafood.

The trainees got along really well—there were times when all we could do was laugh about the absurdity. As someone put it, "C'mon, we're huffing oil!" Some people developed a headache and all of our noses were sore after the first day. Even after the overnight break, by the end of day two, my nose was just kind of raw and sore. But the strict diet the teachers had insisted on also served a purpose: while raw, my nose was also more perceptive. As I was heading into the lab, a FedEx deliveryman passed me by wearing cologne or deodorant—and the scent just knocked me over.

The instructors said we all did really well (no one bombed). We never saw our results, but we were told they would be distributed to the state agencies in case they ever need a screener. Because I regularly work with seafood processors and harvesters and I'm not a regulator, if screening becomes necessary, I can help state health agencies understand the screening process or can accompany a seafood plant inspector who is trained as an oil taint screener as a second opinion. My small part in a region-wide crisis.

Lauren Streib assisted in writing this article.