What types of Germs and Bacteria live on socks and Why are sweaty socks smelly?

A chemist at the University of California, Davis named Gang Sun apparently felt that the smelly sock was a neglected area of research, so he set about finding a solution to this problem.

According to a press release dated October 3, 2000, textiles are a great place for bacteria to grow, and bacteria and yeasts break down perspiration in your socks to create that all-too-familiar bouquet. But Mr. Sun came to the rescue by discovering a method for attaching chlorine containing molecules called halamines to textile fibers.

The chlorine kills bacteria without any unpleasant side effects, no poisonous chlorinated carbon atoms are produced. By finding this practical way of binding the halamines to cotton, Sun is now able to offer textile manufacturers a process that can easily incorporate the anti-smell chemical into the ordinary manufacturing process. The process can be used for single-use products such as diapers and in multiple-use products as well, because the fabric can be “recharged” by washing it in chlorine bleach. The process, says Sun, might also be used for hospital clothing and surgical scrubs.

Sun put his product to the test with a tough group: the U.C. Davis cross-country team. The coach of the team put the socks on both men and women runners and reported with great pleasure that the socks “were comfortable, not irritating, and smelt very mildly of chlorine before and after” they were used. “After an eight or nine-mile run,” she added, “for socks not to smell of feet is a real bonus.” Who could disagree with her? Most people would probably consider it a real bonus for anything not to smell of feet at any time. The University of California has licensed the process to a firm in Seattle that plans to develop it for use not only in socks but in kitchen tools, hospital and prison uniforms, diapers, and incontinence pads as well.

It’s not sweat that smells, in fact, sweat has no odor at all. But get sweat in contact with the bacteria that are your constant companions, and you wind up with a terrible smell because moist clothing is a great place for bacteria to reproduce. Of course, no one ever died from smelling socks, not even those of a cross-country team, so you may wonder about the health benefits of Mr. Sun’s invention. Even when it comes to sanitizing hospital and surgical clothing, as we will see, they are probably minimal.

Perhaps even bigger offenders than feet in producing body odors are armpits. Again, it isn’t the sweat that stinks. Armpits, as one scientific study puts it, are “an area of the body with exceptional odor producing capabilities.” Of course, they don’t use a rude term like “armpit.” They call them “axillary areas,” but that doesn’t make them smell any better. Their exceptional smell-producing ability comes from proteins in sweat that don’t smell by themselves, but release incredible amounts of foul odor when they are used as food by bacteria.

There are several types of skin glands that produce protein-laden moisture in armpits, including apocrine glands, which release part of the gland itself, along with sweat and sebaceous glands, which secrete fatty material, and there are plenty of skin bacteria to live off these nourishing secretions. These microflora include micrococci as well as the bacteria that make the strongest smell of all, the aerobic diphtheroids such as Corynebacterium, the bacterium that causes diphtheria, and Propionibacterium acnes, which can cause acne in those sensitive to it. And of course these germs get on your shirt, or your undershirt, or whatever clothing touches areas of the body where bacteria and sweat get together. So dirty laundry smells bad, too, and it’s the bacteria, some of which are disease-causing under the right conditions, that are causing the odor.

In their web site under a heading called “Understanding Germs in Laundry,” Procter & Gamble sums up a discussion among a group of microbiologists about disease transmission through dirty clothes. Their conclusion is that germs in laundry, insofar as they exist and are transmitted by this route, are probably not much of a threat to health, and Procter & Gamble accurately reports this.

But then, ignoring the results of this discussion among scientists, P&G goes on to eulogize the germ-fighting power of its Tide with Bleach product, with its “patented oxygen bleaching system,” as “the only detergent that sanitizes laundry when a full 285ml dose is used.” In other words, Tide with Bleach will sanitize your laundry (it “Kills 99.9% of Germs”), even though, as our own experts just told us, sanitizing laundry doesn’t really matter.

Procter & Gamble isn’t telling any lies; they’re just trying to sell laundry soap. If there are people out there who want to sanitize their laundry, and there apparently are, P&G stands ready to help them. After all, if you’re selling laundry soap that will “kill 99.9% of germs,” it certainly can’t hurt to make that part of your sales pitch.