Tuesday, March 17, 2009

Reality Czech: Frozen Smelly T-shirts

Back in graduate school a buddy of mine was doing a clinical psychology internship. One day he interviewed an elderly couple—the wife complained that her husband was getting forgetful and confused. “How so?” asked my friend. “Well,” said the wife, “last week I found a pair of his underwear in the ice cube tray in the refrigerator.”

It turns out there are reasons other than Alzheimer’s dementia for people to want to freeze underwear. Take body odor researchers, for example. A standard method for collecting BO is to have the odor donor wear a T-shirt for a couple of days. The BO-infused shirt is a handy scent source—test subjects can rate it for strength and pleasantness of smell, how masculine or feminine it smells, and so on. A popular alternative method is to have the donor wear cotton armpit pads to collect the perspiration.

In BO research one often wants to use multiple samples from the same donor and to have more than one set of judges rate the same odor. The logistics of this can get tricky—a couple of dozen panelists have to arrive at the same time as a group of odor donors delivers the dirty laundry. The easy way out is to store the smelly shirts for testing at a more convenient time. Researchers often put the shirts or pads in plastic bags and freeze them. The rationale is that freezing inhibits the bacteria that turn odorless fresh sweat into stinky BO.

Does this practice work?  Could it distort experimental results in some unexpected way? We had no direct answer to these questions until now. A pair of Czech BO scientists—Pavlina Lenochova and Jan Havlicek in Prague—along with S. Craig Roberts at Liverpool in the UK, examined how freezing—and repeated freezing-and-thawing—affect smell ratings of cotton armpit pads worn by male BO donors.

The upshot of the study, published in the journal Chemical Senses, is that the pleasantness, attractiveness, and masculinity of the samples were unaffected by two weeks or even six months of frozen storage. (The odor judges were 28 young women.) There were some variations in odor intensity but puzzlingly they were not related to storage time.

So the underwear-in-the-freezer gambit looks like an excellent solution to your BO storage needs. As a smell scientist, I can breathe easier knowing this.

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