Clothes Look Clean, but Smell Stinky? Tide® Scientists Help Solve This Mystery

Almost 50% of people report that odors linger on their clothing even after washing

Clothes that smell and stay fresh after washing may help improve mood and performance

It's a conundrum many consumers face—and often complain about: odors that linger on stain-free, clean looking clothes. Now, for the good news: Procter & Gamble (P&G) announced a presentation of new methods for exploring why this laundry mystery even exists. The presentation explained sensory and analytical methods suggesting that, when a detergent ineffectively cleans body soils from clothing, it can cause something called odor "rebloom." These findings, shared by P&G Senior Scientist Kelly Van Haren at the 2018 Society of Sensory Professionals Conference in Cleveland, Ohio, are particularly important in the context of ongoing P&G research suggesting that wearing smelly clothing can negatively impact cognition, mood, performance and creativity.

"We've learned from global surveys that removal of odors is nearly as important to consumers as stain removal and maintaining fabrics' brightness," said Kelly Van Haren, Fabric Care Senior Scientist. "So, it's particularly frustrating for the nearly 50% of people who say their clothes look clean, but still smell bad. To delve deeper into this, we created a new method that relies on complex analytical equipment for highly sensitive findings but also takes into account how most people detect odors on clothes— by sniffing them!"

To measure odor reduction on clothing, Tide scientists used artificial body soils (ABS) dissolved in a solution which were then applied via pipette to swatches of fabric. Then, they used the swatches to identify two primary means of eliminating odor: the first, cleaning the fabric to remove or break-down the ABS odor compounds, and second, how perfume or other ingredients prevent or limit the ability to perceive odor. Fifteen different laundry detergents were blind-tested, and then measured by analytical and sensory assessments one day later. Sensory assessment involved a panel of sensory olfaction experts that compared blind-coded fabric swatches washed with the detergents, to swatches washed in water only. Analytical assessment was conducted via gas chromatography/mass spectrometry equipment and was also blinded.

"Of the 15 detergents studied, a third of them did not clean fabric swatches of odor-causing soils any better than water alone, based on the analytical assessment. However, our sensory panels were unable to detect substantial differences in odors a day after washing with these detergents. Meaning that perfumes in laundry detergents may be temporarily masking the smell of soils that were not cleaned from the fabric," Van Haren said. "Seventy percent of the soils on clothing are produced from our own bodies and are largely invisible to the human eye. When these invisible soils aren't being removed by some laundry detergents, it may explain why clothing that appears and smells fresh out of the wash seems to pick up odors just from sitting in a drawer or shortly after putting on the garments."

P&G is also involved in ongoing research to determine if the cleanliness and smell of clothing affects mood, behavior and even the way we think.

"Our research has previously demonstrated an association between mood and the cleanliness of clothing," says Mary Begovic Johnson, P&G Fabric Care Principal Scientist. "Preliminary results from new and ongoing research even suggest that wearing clean clothes may offer a variety of cognitive advantages—such as improving creativity."

Final results of P&G's ongoing research will be presented at future scientific meetings and the impact of other clothing cleaning trends and challenges will be explored in future research. One such focus is on higher-capacity laundry machines, which have contributed to a 40% increase in the average load-size of laundry in the last five years and led to under-dosing of laundry detergents. Because these machines tend to use colder water, they can also be less efficient at removing body soils, especially greasy ones. P&G is also examining how this affects synthetic fabrics—which account for 64% of global fiber consumption—because these fabrics attract more greasy body soils and are therefore harder to clean.

About Procter & Gamble

P&G serves consumers around the world with one of the strongest portfolios of trusted, quality, leadership brands, including Always®, Ambi Pur®, Ariel®, Bounty®, Charmin®, Crest®, Dawn®, Downy®, Fairy®, Febreze®, Gain®, Gillette®, Head & Shoulders®, Lenor®, Olay®, Oral-B®, Pampers®, Pantene®, SK-II®, Tide®, Vicks®, and Whisper®. The P&G community includes operations in approximately 70 countries worldwide. Please visit http://www.pg.com for the latest news and information about P&G and its brands.

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