According to New York University microbiologist, Philip Tierno, leaving your sheets too long in between washes can turn them into a "botanical park of bacteria”.
In an interview with Business Insider, Tierno recommends washing your sheets once a week.
“Humans naturally produce roughly 26 gallons of sweat in bed every year. When it’s hot and humid outside, this moisture becomes what scientists call an “ideal fungal culture medium.
"If you touched dog poo in the street, you'd want to wash your hands," Tierno said. "Consider that analogous to your bedding. If you saw what was there — but of course you don't see it — after a while, you have to say to yourself, 'Do I want to sleep in that?'"
However, Good Housekeeping Institute recommends if you've been sick with a virus or infection, you should change your sheets as soon as you start to recover to ensure you aren't rolling around in your own germs.
At the very least, bed sheets should be washed once every two weeks, and more often during summer months, according to the French Bedroom Company.
Similarly, if you suffer from night sweats, it's better to wash you sheets a little more often that once a week, up to once every 4-5 days.
A pillowcase should be changed every 2 days according to Koala Product Manager Stephanie Roberts-Baxter. A recent study found that even after a week of washing, the average pillowcase still has over 170000% the number of bacteria as a toilet seat. Per square inch, they contain 24.90% bacilli, 40.76% gram negative rods, 11.58% gram positive cocci, and 22.75% gram positive rods.
In a nauseating revelation, the technical director of Gabriel Scientific, said ‘if you had to come up with a medium to cultivate bacteria, a pillow is pretty much as good as you can get. It is a wet sponge that absorbs bodily fluids of various kinds providing nutrients. It is kept at the ideal temperature by the warm body lying on top.”
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