A new study suggests that hand dishwashing effectively reduces children's risk of developing allergies by 40 percent compared to using the dishwasher.

Researchers at the University of Gothenburg in Sweden found that "hygiene hypothesis" or exposing the children to a few bacteria may boost their immune system and tolerance to different types of allergies.

"If you are exposed to microbes, especially early in life, you stimulate the immune system in various ways and it becomes tolerant," study author Dr. Bill Hesselmar of Queen Silvia Children's Hospital in Gothenburg told Time. "We thought [hand washing dishes] might be important, but we didn't know, so we asked that question."

The researchers looked at the data of more than 1,000 children with ages 7 to 8. The parents of the children completed a questionnaire detailing if their children had eczema, asthma, or seasonal allergies. They were also asked if they do hand dishwashing or used dishwasher at home. They also gave details on their children's diets, according to Live Science.

The findings showed that the children of parents who hand wash dishes are 40 percent less likely to develop allergies compared to those from households with dishwashers. Only 23 percent of children whose parents do hand dishwashing had history of eczema compared to 38 percent of families who had dishwashers.

The results were consistent even after considering other factors such as allergy history in the family, regularl visits to daycare and the presence of pets in the house.

The researchers said that further study is needed to prove that hand dishwashing can be used to prevent allergies.

"It's an interesting finding and very surprising," he told the New York Times. "But we have to see if we can confirm it."

The study was published in the Feb. 23 issue of Pediatrics.