Does vinegar really kill household germs?

Plenty of people swear by vinegar.

It's certainly inexpensive, non-toxic and biodegradable and has been used as a common disinfectant for thousands of years.

But especially if you want to clean your kitchen or your bathroom, you might be wondering about household germs. Does vinegar really kill them?

It seems the answer is a qualified "yes". It's not as effective as commercial cleaners — but it's still a useful disinfectant.

How does it work?

Vinegar, be it white or malt or rosemary-infused, is about 5 per cent acetic acid. The acid kills bacteria and viruses, by chemically changing the proteins and fats that make up these nasties and destroying their cell structures.

When US researchers tested commercial cleaning products against alternatives like vinegar and bicarbonate of soda, they discovered that neat vinegar killed a range of household pathogens.

Science also tells us, for example, that vinegar will kill off the flu virus.

As part of research aimed at preparing us for a flu pandemic, UK researchers found that malt vinegar, much like bleach and washing up liquid, can rapidly inactivate the flu virus.

More recently, US researchers from the Albert Einstein College of Medicine found that vinegar efficiently killed Mycobacterium tuberculosis — the bacteria that causes tuberculosis — after 30 mins of exposure to a six per cent acetic solution.

Professor Peter Collignon, an infectious diseases physician at the Australian National University's medical school, says: "TB is a hard-to-kill bacteria, so the fact that it works against them means most other bacteria will likely be killed by vinegar as well."

Indeed, it could even be an effective and economical solution to laboratories and hospital settings in resource-poor countries.

The bottom line

Nevertheless, when it comes to cleaning the house, keep it simple.

Rather than concentrating on disinfecting surfaces or exterminating all those nasty bugs, Professor Collignon says we should focus on cleaning with hot soapy water.

"You've got to clean the surface first and that's usually enough. Then you have to ask yourself whether you need to disinfect at all," he says.

Good old-fashioned elbow grease is the trick to cleaning effectively, Professor Collignon adds, because you are "physically decreasing the number of bacteria present and washing them down the sink".

The act of rubbing and scrubbing breaks down a slimy matrix around certain types of bacteria, allowing disinfectants, such as vinegar, to get to work.

"Disinfectants work by having a 99 per cent kill [rate] in say 10 minutes," Professor Collignon says.

"That means if there were 1,000,000 bacteria present, there would still be 10,000 left afterwards."

But if you did some basic scrubbing first, you might well reduce the bacteria present to say, around 1000.

If you then use vinegar to take out a further 99 per cent, you could end up with only 10 bacteria: much fewer than the 10,000 you'd still have if you'd relied on vinegar alone, Professor Collignon points out.

As for commercial cleaners, he says we don't always need the level of disinfection in the home that these products provide.

"We over-use chemicals. Instead of using one unit, we use 1000 units, and the benefits are marginal," he says.

"All of us would like to use a magic potion so that we don't have to use the elbow grease. But that's a false premise."

Cleaning house

If you are going to use a product when cleaning, how do you decide which is best? Professor Collignon recommends:

• Asking yourself what you want to achieve. Do you just want to clean or do you really need to disinfect? If you just want to clean, then hot, soapy water is generally enough.

• If you want to disinfect, clean first, then disinfect with the least toxic, most biodegradable product that does the job. Vinegar and alcohol wipes are at the least toxic and most biodegradable end of the scale when it comes to disinfectants.

• Make sure that whichever product you use, you don't damage the surface you're working on. (Vinegar is an acid, so it might not be suitable for all surfaces, and some people find the 'chip packet' smell a bit off-putting).

• Different advice might apply if there's someone at home with an open wound or a poor immune system.