Our world is filled with microbes; the only sterile places are those we create artificially and those that are established naturally in healthy tissues. Healthy blood and muscle and brain and bone are microbe-free, but the world outside your body is filled with all sorts of microbes. For this reason, wherever we go and whatever we do, we are interacting with microbes on a continual basis.
Consider the foods we eat. If we eat raw foods, their surfaces have microbes picked up from the environment - from air and soil and water and interactions with other plants and animals. Even cooked foods are not always microbe free. Our water is sanitized to make it safe for drinking, but acceptable numbers of bacteria can still be found in the best water supplies. We pasteurize foods or cook and seal them in containers, or we dry them or add salt or acids, or we add preservatives, or we refrigerate or freeze them...all these things are done to reduce the negative impact of our interactions with the microbes all around us.
These facts should tell us three things. First, the majority of microbes we encounter are harmless. We are conditioned to believe all "germs" are threats to our health, when in fact most species of bacteria and fungi we interact with in foods and water and air and surfaces are harmless. Pathogens are more rarely encountered than we might expect.
Second, this should tell us we are healthy because we have been designed with very effective and efficient protective systems to prevent infection and disease. Though we contact literally billions of microbes of various types daily, we are rarely ill.
Finally, our understanding of microbiology has enabled food producers and grocers (and even we as consumers) to take actions to keep us healthy by reducing the chance pathogens can cause disease. We do not fully appreciate all of the safety and sanitation engineering that has gone into keeping a city's population healthy - from safe water and waste treatment to food handling guidelines and landfill practices. So while we are constantly interacting with microbes, they rarely lead to negative consequences.
On a regular basis we see evidence that these interactions are frequent and society's practices often are shaped by their presence. How many soaps are advertised as "antibacterial"? How many bathroom cleaners claim to be "disinfectants"? Why are so many dairy products "pasteurized"? Ever notice the signs at city limits stating that the water supply for a city has been approved?
We will use this section to explore the presence of microbes around us and how society has responded to their presence in our home environment, in our foods, and in other household products.