Re: what are the best house held cleaning product that kill germs

Dislcaimer:
Let me first say that I do not work in the area of disinfection or on the 
development of agents active in disinfection or sanitization.  I do not have 
direct knowledge  of these products effectiveness nor have I  performed 
experiments on the effectiveness of commercially available products.  The 
comments I make are not an endorsement of a particular brand of household 
cleaner nor am I making any claim that disputes the claims made by the 
manufacturer.  I am not suggesting that these products be used for a 
particular purpose or am I giving any advice for which I can later be held 
liable by acting as an expert.  I am simply making general statements about 
the types of chemical disinfectants that one may find on the market today 
and using common name brands only to illustrate that these products claim to 
contain these ingredients. 

Answer:
I need to first make your question a little clearer.  You ask about the 
killing of "germs".  This is actually not a scientific term, although it is 
commonly used.  For our purposes let's talk about bacteria and viruses that 
are commonly considered to be harmful to humans, the microbes we call 
pathogenic.  That's really what we want to kill with our household 
disinfectants anyway.  Also, let's be clear that household disinfectants do 
not kill all of the bacteria or viruses on a surface.  Sterilization is the 
process in which all living organisms, including tough bacterial spores, are 
killed.  This can be accomplished with very harsh chemicals like strong 
acid, or with gamma rays, fire, dry heat, or a pressure cooker.  Household 
products will not sterilize.  Some living organisms will remain after 
treatment.  Household products either degerm, disinfect, or sanitize.  The 
difference is the level of cleaning.  Degerming would be the equivalent of 
dishwashing (without antibacterial soap).  Normal soap and mild detergents 
do not kill most organisms.  The bacteria or viruses are simply lifted from 
the surface by breaking the surface tension of water and the suds then trap 
the microbe so that they can be washed away.  Many microbes, even those that 
cause human disease, the pathogens, can remain.  Disinfection lowers the 
number of pathogens more substantially, to a relatively safe level.  
Sanitization  lowers numbers even more.  In these processes, chemical agents 
actually kill bacteria, viruses, and fungi.  Disinfectants need to be 
distinguished from antibiotics and drugs.  Disinfectants have a non-specific 
(very broad) mode of action.  They will kill anything, including you, if 
applied properly.  This is one reason why household cleaners need to be kept 
away from young children and used with care (like rubber gloves).  
Antibiotics are magic bullets that have a very specific mode of action.  For 
example, penicillin only kills a certain class of bacteria.  It does not 
harm humans at all.  It does not harm viruses at all.

OK.  On to household cleaners.  There are several classes of disinfectants 
that are commonly found in household cleaning products, often in 
combination.  The effectiveness of a disinfectant product is increased by 
mixing two  disinfectants.   I've gone around my house looking at the labels 
of my household cleaners.  It seems to me that all of them would be 
effective in killing bacteria and certain viruses.  None of them appear to 
be very effective against bacterial spores.  There were some strong chemical 
agents.  Bleach (sodium hypochlorite or hypochlorous acid) and bleach 
solutions are strong chemical agents effective in killing microbes.  
Solutions of strong base, like sodium hydroxide, are also effective.  This 
is commonly found in toilet bowl cleaners.  Very strong and very effective.  
"Mr. Clean" is simply a solution of sodium hydroxide (lye) with some 
"degreasing" agents (likely a mixture of detergents and soaps).  

There were several products that contained a mixture of a special class of 
detergents (surfactants) that are commonly called QUATS (quaternary ammonium 
salts).  These are very widely used disinfectants.  They find their way into 
toothpastes, mouthwashes ("Cepacol"), deoderants, and household cleaners.  
"Formula 409" contains a mixture of these QUATS.  These chemicals disrupt 
cell membranes leading to cell death.  They can also disrupt the membranes 
on some viruses.  "Lysol II" also contains QUATS.  This includes Lysol brand 
toilet bowl cleaner and the Lysol II disinfectant spray.  The spray also 
contains 79% alcohol (ethanol).  The alcohol itself when mixed with water 
(70% alcohol and 30% water) is a very effective disinfectant.  It's what I 
use in the lab all the time.  So, together with the QUATS, the Lysol II 
spray seems like it would be very effective.  In fact, the company claims 
that it can sanitize surfaces and kill a wide range of microbes.  You can 
find QUATS on the label by looking for something like "alkyl dimethyl benzyl 
ammonium chloride" or "benzalkonium chloride".

The original Lysol brand cleaner falls into another class of disinfectants, 
the phenolics.  These are chemicals derived from natural plant materials or 
from coal tars that have some resemblance to the compound phenol.  The 
active ingredient in Lysol is phenyl-phenol.  It can disrupt membranes and 
cause enzymes to unfold and stop working.  "Listerene" falls into the class 
of phenolics, being a mixture of plant-derived compounds, like eucalyptol.  
It was discovered by Joseph Lister, the man who first used disinfectants.  
He noticed that doctors who washed their hands before surgery had fewer 
infections in their patients.  He found that washing one's hands and the 
wounds with phenol reduced infections.  We don't use phenol today because it 
is harsh, smelly, somewhat toxic, and irritates wounds.  But the idea of 
reducing the number of pathogenic bacteria and viruses was a good one.  
Today we rely on disinfectants to make our lives safer.

Many products today contain triclosan.  This is found in antibacterial soaps 
and toothpastes.  It is somewhere in between a disinfectant and a drug.  It 
is a phenolic compound, but also may target specific enzymes in the 
synthesis of fats.  It is not clear to me that its use in many of today's 
products is effective.  Mainly because the doses used are so low.

I am sorry that I didn't directly answer your question by saying that 
product A is better than product B.  Most will kill much of what we are 
usually worried about, namely Salmonella, Staphylococcus, Streptococcus, 
Campylobacter, Shigella, Escherichia coli, Athletes Foot fungus, viruses 
like Herpes, and many other potential pathogens.  I have not read any 
specific reports comparing these products under a variety of conditions, 
using a variety of pathogens.  In my microbiology lab, I use bleach 
solutions, 70% ethanol, and diluted Lysol liquid.  But I am not trying to 
protect a finish or preserve vibrant colors, and after years in the lab, I 
am kind of used to distasteful odors.

I hope this helps.

Cheers,

Dr. Mark Schneegurt.