Anyone with a TV will be familiar with the ads for cleaning products claiming to kill "99.9 percent of household germs", usually featuring an attractive young mum, a couple of messy but delightful children and a Golden Retriever.
But what is the actual deal with household germs? Are they really that bad for you, and therefore deserve mass elimination? Or does destroying them actually do more harm than good?
"Firstly, there has been quite a lot of research in this area which tells us you have to specify the difference between the domestic cleaning to remove visible dirt, which you do for aesthetic reasons, and the cleaning you do for safety reasons," Danilla Grando, Associate Professor of Clinical Microbiology at RMIT University, told The Huffington Post Australia.
"There is actually very little evidence that spraying the house with disinfectants makes any difference to the amount of microbes in that environment.
"Domestic cleaning is a very different thing to hygiene."
Wait -- so what about killing 99.9 percent of household germs?
"If you were to spray an area with that product, you would kill the bacteria -- let’s call it that rather than germs, as that term tends to have negative connotations -- on that surface," Grando said. "The spray will kill just those organisms there, but within seconds, new bacteria will settle down from the air and replace them.
"As I said, domestic cleaning is very separate from hygiene. Hygiene comes into play when there is a risk of disease transmission."
Okayyy then. So spraying your kitchen head to toe doesn't really seem to have any impact on the microbes dwelling there, but it does make it look shiny and smell like lemon. However, hygiene is a different ball game and should be taken seriously. Got it. We think.
"What we need to do is help people understand microbes better. Like when I talk to my students, I tell them that we live in a garden and that we have internal soil. In that, we have bacterial companions, and they are like pets. They are actually really good for our health," Grando said.
"Living in an environment of microbes is a good thing, and it's actually really important we have exposure to them. After all, 99 percent of them are good, only a few are bad. What we need to do is look for the opportunities where the bad ones can cause disease."
Grando goes onto clarify that doesn't necessarily mean wiping down the bench every three seconds, but has more to do with healthy behaviours such as good hand hygiene.
"Hand washing after using the toilet is important, because we can carry resistant bacteria in the gut," Grando said. "Another one is hand washing after playing with pets, because sometimes pets can harbour organisms that can be bad if ingested.
"I would also encourage hand washing before eating food. Something going straight from hand to mouth can be a source of disease transmission."
Grando also says hygiene is particularly important at this time of year, when cold and flu season is just around the corner.
"That is actually a reason we would clean surfaces, because when people sneeze, they spray big droplets of mucus everywhere. And that mucus actually protects viruses.
"That's why it's good to 'blow and throw' -- by that I mean to blow your nose and then throw out the tissue. You don't want to keep trying to use the tissue until it’s so soggy you're spreading mucus around.
"It's also important to wash your hands regularly."
In terms of other hygienic tips, Grando says it pays to have a small bottle of hand sanitiser on hand when travelling, and to be mindful when handling raw meat in the kitchen.
"Of course you should always take special care preparing food, particularly raw meat, poultry or fish," Grando told HuffPost Australia.
"Don't get distracted and go walking around answering your phone when you are in the middle of preparing this kind of food. Wash your utensils and boards very quickly after you finish with them, and use separate knives and boards for your veggies."
As for your house being "too" clean?
"That's something that has been spoken about a lot over recent years -- the hygiene hypothesis," Grando said.
"At this stage, a lot of scientists have written reviews, but there is very little evidence to say all the allergies we are seeing in the current day and age is due to living in too clean an environment.
"When it comes to the link between over-cleaning homes and allergies, there is very little actual evidence available to support that."