Most people would not be hard-pressed to name what’s in their fridge. Milk, eggs, raw chicken and leftovers are likely candidates. But these visible items are just a fraction of what lives in this appliance, which is also home to many species of bacteria and other microorganisms.
A team of researchers at North Carolina State University this week set out to identify just what tiny creatures inhabit people’s refrigerators – and what else is living in their homes.
In the coming months, 500 American households (10 from each state) will get the chance to collect samples in the home — from couches to counters to people — and submit them to researchers for identification.
From this project, “The Wild Life of Your Home,” scientists hope to get a clearer picture of the microscopic species — both dangerous and beneficial — that people encounter on a daily basis.
The idea is to figure out what types of organisms develop in which environments, says Rob Dunn, a biologist at NCSU and the study’s lead researcher. These areas can be as big as regions of the country and as small as a corner of the house.
“In our houses we all have these teeny tiny habitats,” Dunn explained in an interview with Food Safety News. “And we think of them as sort of all being ‘modern,’ but they’re actually really different in their characteristics, so the species we would expect to find in different parts of the house are likely to be very very different.”
For example, past studies have discovered a new type of bacteria that is unique to shower curtains. It is chlorine-tolerant, and can survive the harsh climate of the shower, which ranges from wet to dry and back again.
Refrigerators share a similar story, says Dunn.
“The truth is that refrigerators are this really interesting place, because they’re quite cold and so likely to favor a unique set of species that’s evolved to deal with the cold.”
Bacteria can even differ depending on what type of food is in the fridge, Dunn says.
“A vegan refrigerator should be different in terms of the microbes it has from a Midwestern meat-eater’s refrigerator,” he says.
He also notes that a greater presence of bacteria doesn’t necessarily pose more of a health threat. In fact, this could even be a good thing.
“The dominant theory has been to look for bad things, and so most studies that people do on our houses are about bad things, but the truth is that most species that live in our houses either have no real effect on us or are actually good,” he says.
Cleaning chemicals designed to kill bacteria can kill good bacteria along with the bad, or can weed out weaker organisms, leaving the stronger ones to multiply and develop a stronger resistance to these substances.
One species of bacteria known to live in sink drains actually eats tricoslan, an antimicrobial used in wipes and detergents, says Dunn.
This study may show that members of households with a greater presence of bacteria are in fact less prone to allergies and certain diseases than those who live in “sterile” homes.
“Our intuitive paradigm is, ‘Kill all the bacteria and you’ll be healthy,’ ” he says. “But the truth is probably ‘kill all the bacteria and you will have a house full of stuff that’s tougher than you.'”
Instead, Dunn says, it might be time to take a look at bacteria whose presence can be beneficial.
“People talk a lot about probiotics, but there aren’t a lot of data, and so this will be really interesting in that regard.”
Another thing that will make this study talked-about will be its public nature. Information on what organisms were found in what region will be posted online as they come out, so that anyone — scientist or just the intellectually curious — can help identify patterns in the data and figure out why certain species show up where they do.
“A lot of science is sitting around in your chair spinning and thinking about what could be going on, and that’s something everybody should be able to participate in,” says Dunn, who introduced this novel approach during his last study, which looked at organisms found in the human belly button.
As for those never-before-identified microscopic boarders that might crop up in people’s homes, Food Safety News wanted to know if they might be named after the study participants who find them.
Dunn’s answer is encouraging.
“That seems totally appropriate to name a few after dedicated citizens who’ve made discoveries where no one was willing to go before.”