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  • Feature Story

Sniffing Out Diaper Odor With Science

August 21, 2018

A woman wearing a white lab coat carefully lifts the top from a glass jar and leans over to delicately sniff the jar’s content. The contents are not perfume or a decanted bottle of red wine – the jar contains one perfectly placed diaper. Looks strange, of course, but this interesting array of glass, synthetics and sniffing have been carefully orchestrated in the name of science.

Melissa Lohnes, lab manager for the sensory lab at UL’s consumer testing facility in Canton, MA, explained it this way, “Manufacturers want to know how well their brand of diaper performs compared to the competitors.”  In this case, which diaper most effectively absorbs odors.

Scent can play a major role in establishing a consumer’s preference for a diaper brand. If the smell is not acceptable, a parent will change brands and stop buying the product. Rightly or wrongly, offending odors often signal “poor quality” to many consumers.

Determining performance

To test how well a diaper reduces odor, a lab technician places synthetic urine on the inside of the diaper; a process referred to as “insulting the diaper.” Synthetic urine is a combination of sodium chloride, urease and other chemicals that produce an odor similar to ammonia or urine when mixed together. Interestingly, synthetic urine is colorless as the presence of color could negatively influence test results.

The product sits in what is literally a traditional cookie jar, for a set amount of time before a sensory judge evaluates the intensity of the odor. Samples typically incubate for two hours and eight hours post-insulting.

Once the jar’s incubation period is over, a UL technician rolls to the sensory panel room, a sparse space furnished with one table and a line of individual booths outlining the room’s perimeter.

Related | Private label product testing helps establish quality in the marketplace

Sniff sniff

Five judges enter the room, moving to his or her assigned spot to wait patiently for the manager’s instructions. The test begins, and each judge lifts a jar’s lid, sniffs once or twice, and closes the jar.

As Lohnes explained, the judge is evaluating the odor intensity of each jar. “The goal for the client is that the intensity of smell will decrease over time,” said Lohnes.

After each jar’s assessment, the judge marks the appropriate box for the sample and moves on to the next jar. The assessments are gathered and calculated at the end of the test when an analysis is performed to determine if there are any statistical differences between an uninsulted sample and an insulted one.

“Manufacturers want their product to perform significantly better than the control; they want the odor intensity to be lower because then they’re proving that their product works,” added Lohnes.

Sensory odor panels can be performed on any number of products, from puppy pads for housebreaking to incontinence products for adults.

Lohnes explained that the lab reports product testing at the 95 percent confidence level. “What that means is if we were to rerun the test, we feel we could repeat the results 95 percent of the time.”

A win-win for consumers and manufacturers. Reliable products equal happy, loyal customers and positive returns for retailers.