hey everybody doctor over here this is one of my favorite groups of chemical control agents you have the per oxygens if you've ever been in a lab with me you know I feel about using hydrogen peroxide as a as a wonderful disinfectant so how they work is just remember that hopefully you've seen the earlier videos about oxygen requirements for growth that that all living things that are exposed to oxygen have to deal with it we think of oxygen is a good thing but oxygen creates all sorts of toxic forms and if you don't have the machinery to deal with toxic forms of oxygen it's going to cause lots and lots of problems even if you do have the machinery to deal with it like we do it still leads to problems over time so you see here the how these work it says oxidation which would you be the peeling off of electrons and destabilization of cellular macromolecules let's put that in English they work by creating free radicals so the most common free radicals are called reactive oxygen species so the proxy genes are gonna generate a ton of reactive oxygen species and if you're an anaerobic organism they can't deal with any of them it's gonna wipe you out if you're an organism like us or many of your obligate aerobic bacteria then they're gonna have the enzymes to neutralize some of these reactive oxygen species some of these free radicals but you can overwhelm them so the key with hydrogen peroxide is to use a high enough concentration if you dilute hydrogen peroxide so hydroxide the other Protestants too we'll talk about hydrogen peroxide first but if you dilute hydrogen peroxide too much then it may not kill all organisms but I've worked in the lab for 12 years now my mentor worked in lab for 27 years and we both agreed that hydrogen peroxide is a wonderful way to kill the microbes in a microbiology lab so all right let's uh so that's kind of the proxy genes in general let's talk a little bit more about hydrogen peroxide so by far hydrogen peroxide known as h2 o2 you can see on the image there is by far the most widely used per oxygen so it can be used as a disinfectant and an emic antiseptic it can even be used as a gat in gases so a lot of times they'll spray like steams or gasses of hydrogen peroxide when they're creating aseptic packaging like for food and these kind of things so I already told you how it works it generates a whole bunch of free radicals that that organisms can't deal with any some can deal with some but if you overwhelm the system it will kill pretty much anything so here we see just in this image the reason I shared it a couple things you see a bottle of hydrogen peroxide notice those bottles are always dark because light can inactivate hydrogen peroxide and on the right you're looking at a contact lens cleaner and that bubbling is actually the enzyme catalase that takes hydrogen peroxide and creates water and oxygen out of it so when you put hydrogen peroxide on a wound and you see a bubbling it's not so much evidence that it's working if anything it might be evidence that it's not that it's being inactivated so I'm definitely not big on hydrogen peroxide being used on on deep wounds you know surface scrapes those kind of things are probably okay but this is why you do have to make sure you use the right concentration of hydrogen peroxide because you're dealing with an organism that has enzymes like catalase they will be able to neutralize a certain amount of it all right so that's hydrogen peroxide next we have peracetic acid on the list here so a peracetic acid how I've seen this being used it is effective against some of the organisms that may be hydrogen peroxide can't deal with because they have the enzymes that can break it down peracetic acid it can be used as a liquid but also as plasma I'll cover what plasma is later but it's the you can actually create um disinfectants that are the fourth state of matter that aren't solid liquid or gases the reason peracetic acid is so good is that it really really effective at killing spores which are always a big concern I've seen it used mainly with fruit like like spraying it on fruit and those counting's at this point but I will think you I think you're gonna see more peracetic acid or I believe they call it PAA in the future a couple more here so benzoyl peroxide and then carbamide peroxide benzoyl peroxide maybe you've heard of as an acting medication so it's used to kill pro prion a bacterium acne which which which is associated with acne doesn't cause it in all cases but certainly is associated with it and then carbamide peroxide this is you're gonna see this one used in toothpaste so it helps to kill the pathogens that in the mouth like septic you know streptococcus mutans that can lead to cavities and also it helps it helps to disrupt the biofilms these organisms like to hide behind and then of course the carbon Proc side can also play a role in keeping your teeth from getting discolored so so those would be some examples the last example is ozone so I'll do more videos on water treatment separately later but ozone is oh three unlike atmospheric oxygen which is OH - so ozone can be used to treat water it's been I think at this point in the United States it's used in about five percent of municipalities but it's if if maybe chlorines not doing the job or you want to make sure your water is safe you can use ozone there as a water treatment all right so those are your per oxygens hydrogen peroxide peracetic acid benzoyl peroxide carbamide peroxide and ozone gas very very effective at controlling microbial growth okay have a wonderful day be blessed