Go to any supermarket and you will see an entire aisle stacked with dozens of different cleaning products. Turn on the television and you will be inundated with advertisements starring super-cleaning moms, who are doing their darnedest to keep themselves, their children and their houses spotless.
The ability to make a house shiny is greater than ever thanks to the proliferation of cleansers, anti-microbial agents, detergents and bleaches. But is a shiny house clean?
There is even speculation that in our frenzy to be fastidiously clean, we may in fact be injuring our environment and ourselves.
"There is a school of thought that remains to be proven that many issues that people who develop allergies have, may be associated with having a hyper-clean environment. There are studies that show that disturbances to our microbial population may have links to the incidence of diseases such as diabetes, autism, auto-immune diseases and cancer," said Dr. Norman Neumann.
The associate professor in the University of Alberta's Department of Public Health is researching the effects of biological hazards that may be relevant to global human health.
Neumann believes that the "what is clean?" argument likely began in the seventeenth century soon after Antoni Van Leeuwenhoek, the father of microbiology, got his first glimpse at what we now call microorganisms. Van Leeuwenhoek examined his own feces under a microscope and determined that "animalcules" lived in the substance.
Van Leeuwenhoek's discoveries were a huge breakthrough in human understanding of bacteria, but scientists are once again on the verge of an equally great discovery about our microbial makeup, Neumann said.
"We are on that kind of scientific pinnacle again. What does clean mean? Our understanding of clean and our hygiene hypothesis will likely change in the next 10 years," he said, adding that the trick to finding clean will involve finding a happy balance that allows us to co-exist with our own little "animalcules."
"Humans have ten times more bacteria cells on their body than they have of their own body cells. And the bacteria living on me are different than those living on you. Those bacteria play a huge role in who you are and an important role in your body functions," Neumann said.
The bacteria even live with their own viruses.
"Each human has tens of trillions of bacterial cells. And each of those bacteria cells has at least one virus and more likely multiple viruses on them," he said.
The whole complicated organism, the bacteria in our guts, in our mucous, on our scalps and on our skin, along with all of their viruses and all of our own individual human cells, live together as a rich community.
Hand washing
Neumann stressed that maintaining a state of super-cleanliness is imperative in hospitals where many patients have compromised immune systems. At all times, whether in hospitals or in our homes, careful hand washing is vital.
"We know that in the context of disease transmission, the most effective way to interfere with the bacterial chain and with the cold virus is hand washing," Neumann said.
Even if a counter or multi-use computer appears clean, someone who just sneezed may have touched that surface, but constantly cleaning the counter may also be counter-productive, Neumann said. Instead, to interfere with the bacterial-transmission chain, keep your hands away from your face.
"Keep your hands away from your face. Don't pick your nose. Don't chew your fingernails. Don't stick your fingers in your ear and don't pick your teeth. And if you sneeze, don't cover your nose with your hand. Turn your head into your arm," he said.
Most soaps emulsify or break down particles to allow water, which is the greatest cleanser of all, to work more efficiently.
"In laundering, detergents emulsify the particles to help wet things and release dirt. Detergents swell the cloth helping water, which is the big cleanser, to get in. On a counter, the wiping is more efficient with water. That's why we don't use a dry cloth," said Professor Rachel McQueen, of the University of Alberta's Human Ecology Department.
Cleaning with hot water versus cold water makes a difference in some instances, but not all, said Neumann as he explained why people must clarify their own objectives when they start cleaning. They need to define their own meaning of clean and whether they are content with something that appears spotless or something that is almost sterile.
"Some cold-water clothes-washing detergents may be used, and will get out stains. That's different than disinfection. Disinfection goes up as the temperature goes up," Neumann explained.
Soap is more effective when used with warm water because the bacteria we live with don't like being too hot any more than we do.
"Putting your hand in water that is 60 degrees Celsius or hotter is uncomfortable. It's the same for bacteria," Neumann said.
Toxic bleach
Bleaches and anti-bacterial wipes differ in the way they clean but in the end, both kill bacteria.
Most disinfectant-style cloths, the kind that are pulled one at a time from plastic containers, clean with the help of an ethanol-based alcohol that does not have lasting effects on the environment.
"Most disinfectant cloths have a lot of alcohol and tend to kill bacteria and then evaporate quickly. They are a broad-spectrum anti-microbial cleaner and they sterilize the surface quickly but not necessarily for the long term, which is good," said McQueen.
Bleach is a rapid toxin that very readily kills all bacteria, but it has both good and bad properties. It also takes the colour out of fabrics and countertops. It makes sense to use less, rather than more, said Dr. Greg Goss, a toxicologist and the director of the University of Alberta's Water Initiative.
"Bleach is extremely potent but it's not nice on the eyes or respiratory system. A tiny amount of 1 to 100 dilution will kill bacteria and a thimbleful of bleach in a 10-litre pail will kill fish," Goss said.
Even in a household where seasonal colds and flues may have taken hold, a little bleach goes a long way, Goss said, stressing there is no need to liberally slosh gallons of bleach on every surface.
"In the bathroom, one tenth of a cup of bleach will kill every bacteria and it will do it very quickly – in 30 seconds," he said.
Goss's primary concern is with what all those household cleansers do to the river water.
Chlorine bleach is easily removed from water but some of the newer anti-microbial soaps, containing nanomaterials cannot presently be easily removed and are potentially harmful to the environment.
"My job is to ensure the safety of our water for all Canadians," Goss said as he explained that he is working to have nanomaterials removed from general use.
"Soaps containing nanomaterials such as nanosilver have been shown to have potentially adverse environmental effects. The concentration is low presently in Edmonton, but in high amounts, nanomaterials can cause male fish to turn into female fish," Neumann said.
With the environment always foremost in his mind, Goss said that in his own household he tries to limit the amount of cleaning substances that are used, even when one family member is ill.
"In our house we primarily use very little in the way of cleaning agents. We use a little vinegar and a little bleach. If someone has the norovirus or a cold we may wipe the counter with alcohol-based gels and we wash our hands thoroughly with hot water because hot water kills bacteria," he said.
Touching bacteria with your fingers is not a worrisome issue, Goss said, because simple touching does not allow a virus to enter the body.
"Skin is very impermeable. I can put even the most toxic bacteria on my skin and it will not cross. As soon as I touch something else, I transmit it," he said.
For the most part, the other two scientists agreed with Goss. They try to limit their use of cleansers because they want to preserve the integrity of their own microbial ecosystem.
McQueen said that she is most careful in her kitchen when she cuts up chicken and at those times, she bleaches surfaces and boils cleaning rags, otherwise she washes normally.
But Neumann said he could not definitively answer the question about what is clean?
"I don't know the right balance. Would I encourage the use of anti-bacterial disinfectants as a habit? The answer is no, because you may be hurting yourself more than you are helping. If we have a norovirus in our house, and someone is vomiting, we scrub the toilets often with Lysol. We isolate that person as much as possible, we wash our hands and we hunker down and wait for it to go away," Neumann said.
