Stacking dishes wet may promote bacterial growth

August 14, 2001 in Food Safety, Nutrition Topics in the News

Stacking dishes wet may promote bacterial growth

Researchers are cautioning that the plates on which commercial meals are served may become contaminated with bacteria if they are not allowed to dry properly before being piled up after washing.

Cleaning and stacking and holding dishes in a catering operation or church kitchen may become an issue if dishes are stacked wet and then held for a long period.

Researchers at the Oregon Health Sciences University in Portland assessed whether stacking wet dishes in commercial establishments may contribute to the growth of harmful bacteria on plate surfaces.

The researchers first identified bacteria on 100 dishes (prior to washing) that had been used to serve meals to patients at a medical center. They then put half the plates through a full cycle of a dishwasher, stacking the plates after placing small amounts of water on each dish surface. The other 50 plates were machine-washed and then allowed to air dry for 24 hours.

Although no difference was found after 24 hours, after 48 hours a significantly higher amount of various bacteria were evident on the wet-stacked dishes.

The researchers pointed out that the US Food and Drug Administration code specifically recommends air-drying of all commercial dishware in order to prevent such food contamination problems. Consumers and food-preparers should pay attention not just to what they eat but to whether or not what they eat is safely prepared.

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