© Distribution of this video is restricted by its owner
Transcript ×
Auto highlight
Font-size
00:00 Okay, that's kind of yes. start. Alright folks. Welcome.

00:33 . So as you know, I you know exam one later this

00:40 Uh Let's see, so make sure sign up for a slot to take

00:46 exam. Um what else? Chapter . Okay, so chapter five,

00:51 gonna start and finish that today and put some questions. These are like

00:57 from a previous uh blackboard quiz or exam questions pertaining to chapter five

01:05 Uh There's like five or six questions , so and the answers are On

01:11 as well, so um smart Let's see. So chapter five was

01:17 back to the due date was pushed to next week. So if you

01:22 it already fine, but since we're getting it to it today, I

01:28 pushed it to the next Monday. . Um all right. Uh any

01:37 ? Okay. Nothing. Yeah. many questions on the exam does anybody

01:48 the answer to that? What's what it? Right man. About how

01:55 questions I'm seeing, Who's read the . 35 to about 30. Uh

02:02 . 35. 36. Somewhere in in an hour on the exam.

02:07 . Um many else. Okay, we ended I just want in case

02:16 have any questions before we move on five. We ended with um endospore

02:25 . All right. And so the of uh in the spore forming

02:32 the different cell types you would Um under the microscope. So you're

02:39 cells, cells with spore forming some it's already done and it's just a

02:44 endospore and the process I guess if had to encapsulate this in you know

02:52 a few words I'd say it's a is going on in the process.

02:59 a pursued by DNA replication because we're to create a in those four that

03:06 have of course the D. A. Of the organism in

03:09 Um And then you have the other that's kind of directing the process through

03:15 on different genes et cetera the mother doing that and then engulf mint to

03:21 a double membrane. Okay. And we deposit a cell wall in there

03:29 deposit some other chemicals in there to it, remove a good portion of

03:35 from the structure and so that's all going on in this. Of course

03:40 spore being formed here. Okay. remainder of the cell basically just

03:46 Okay And you're left with a free at the end which can germinate.

03:53 . It's just think about that as seed planting a seed in the ground

03:57 adding water. Right? It begins can begin to grow. So that's

04:02 what the nature of in the free those four state or free sports

04:07 That's what that is very resistant. survive hundreds thousands millions of years um

04:14 the right conditions. But there any questions about. Okay so chapter

04:21 Right so we only really covering two of the chapter one being a road

04:33 which is basically the various types of that the right word. But various

04:43 , bacterial cells, Archaea will have oxygen. And there's and they're they're

04:48 . There's basically five different responses that organism can be an organism better way

04:55 say bacteria. Archaea itself can be in terms of its zero tolerance.

05:02 , basically bowling down to can you oxygen as part of its metabolism

05:08 Right? Um Can it does it it is it go two ways?

05:14 it can it use it or can use it? Right. Um There's

05:18 there's a lot of types that can that they can live with or without

05:21 . And there's types that don't use at all but live within the environment

05:25 02. Okay. And others that at the other end of the spectrum

05:30 killed by the presence of oxygen. . So it spans the spectrum.

05:36 really this chapter is about kind of two halves. The first part.

05:40 you read through the whole thing, that's what you want to do,

05:43 fine. It's kind of different environmental on growth. So ph temperature um

05:54 . Um oxygen. We'll talk about the oxygen aspect. Um And how

06:01 influence growth. So in the second of this is really how do we

06:04 these things? Right? It's about microbial growth disinfectants, antiseptics, antiseptics

06:10 sterilization and so forth. So that's we'll focus on that and start with

06:15 little bit of about zero tolerance. um the so in terms of

06:22 Okay, we'll learn begin to learn this in a couple of weeks.

06:27 reminds me um so friday, I thers, excuse me, thursday.

06:32 , thursday's lecture. None of that on exam one because that begins the

06:38 unit. Right? So we start um two on thursday. And that

06:43 is all that folder has been opened . So you have access to that

06:48 as of last week. So anyway what we're gonna cover. So oxygen

06:54 . So we'll learn a couple of as we begin to get into metabolism

07:00 like colossus of respiration etcetera and other of metabolism. That oxygen of course

07:08 one of the more common molecules. . Of course we use it right

07:14 our metabolism respiration. Um Of well not of course, but you

07:21 or may not know that oxygen of is itself somewhat reactive can be made

07:27 reactive by um turning it into one these what we call free radicals.

07:34 , so basically oxygen can become reduced this form called the super oxide

07:42 So other reactions can occur involving things hydrogen peroxide that can lead to the

07:49 of hydroxide radicals. The bottom line is these three species and there's

07:54 But these are the three main ones are very uh reactive and can interact

08:00 cellular components, proteins, nucleic acids in the process can damage these

08:06 Okay. And this and this were are susceptible of this as well because

08:12 course ourselves respond using oxygen. So it's a byproduct oxygen metabolism. Part

08:20 that is a byproduct where oxygen itself be reduced by enzymes in this respiratory

08:28 . We haven't talked about this That's that's coming. But but for

08:32 , just know that the components that up respiration, the enzymes involved,

08:36 of those can interact with oxygen and the super oxide radicals react and others

08:42 reactive molecules that can damage cells. . Um and so our cells have

08:51 to this. So if you if are a microbe living in a oxygen

08:58 world. Okay, this is what have to contend with. Whether you

09:02 oxygen or not, right. Whether use oxygen or not, oxygen itself

09:07 still get into the cytoplasm, can with enzymes and some of them may

09:15 these these reactive molecules. Okay, again, whether you use oxygen or

09:21 , you can be susceptible to the . Okay, so that means then

09:27 do you prevent this? You have against that? You have enzymes that

09:32 neutralize kind of the effects of these as they're produced. Now, I

09:38 I wouldn't don't think of this as the the radicals themselves are not long

09:46 but of course they can cause Right? It's about how they can

09:50 produced continue to be produced in the of oxygen but they can quickly go

09:55 but you still have to contend with there continue to be produced and you

10:00 to neutralize them if you're going to succumb to the damage. Okay.

10:05 and so we have things like We call protective enzymes. Okay.

10:11 so here's the formation one example of formation of the super oxide radical.

10:16 don't you don't need to memorize the reactions that create these things more.

10:20 just what's what are what are if see the term um reactive oxygen

10:26 you know what that means? And types of molecules to see associated with

10:29 . But I'm not gonna ask you derive the chemical equations that generate these

10:34 . But anyway so here's one protective . This S. O.

10:39 Is the short name or super oxide me taste. So it basically will

10:45 that into hydrogen peroxide which then undergoes conversion to eventually water and oxygen through

10:54 . A's If you've ever had a put hydrogen peroxide on a on a

10:59 . Right? Um And you'll see bubbling. And that bubbling is your

11:03 blood cells basically producing cattle A's uh create the auction bubbles. So um

11:12 is another one. You have this well. Okay another way to to

11:16 the effects of hydrogen peroxide again forming . Okay so we have ourselves have

11:23 three of these. Okay um here and in here. Okay so um

11:35 again in terms of bacteria archaea and they respond. Okay depends on how

11:42 use oxygen if they do or not . Regardless of that. They still

11:47 protection if they're going to live in oxygen world. Okay. Um But

11:53 choose not to do that. They avoid it altogether. Okay. And

11:57 are your different classes of of zero if you will. Okay. Um

12:04 so how do we um evaluate How do we determine what is what

12:11 terms of their era tolerance? So medium is what's called fluid five likely

12:17 . Okay. Um It's it has in there that will bind up

12:25 Okay. It's a it's a semi media. It's kind of jelly like

12:32 . Okay so when you prepare it you of course uh then boil

12:38 Important tubes boil it that drives out air. But then of course they're

12:45 . It's capped but then air can seep in again. Okay But you've

12:50 the gel like matrix that kind of diffusion of air into the into the

12:58 . Okay. And you've got chemicals combined up oxygen. Okay. The

13:02 result of all that is you're creating great of oxygen where its highest at

13:08 top and none at the bottom. so a range of oxygen levels in

13:14 that. Okay so there's your so inoculated tube of this, you've got

13:21 tube with varying levels of oxygen top bottom. Okay. Hi top.

13:24 of the bottom. So then you to inoculate an inoculation is done by

13:30 a wire loop. Okay? And it through the entire length of the

13:37 because you want to because you don't what this microbe is capable of

13:42 That's what you're trying to find out doing this. So you want to

13:45 sure you seed it right? Plant , if you will all along the

13:51 length of the tube. Okay. so you then of course incubated and

13:57 have to let it grow for 12 hours. Okay. And what you're

14:01 to see is what the cells that , where are they, what zone

14:07 they growing in? Okay. So are they growing just here?

14:13 So what you'll see of course is cloudiness. A turbidity where they're

14:20 right? That represents lots of lots of growth. So maybe you

14:24 see that turbidity at the very Right? Or maybe you see it

14:28 the middle only in the middle and else. Maybe you see it only

14:32 the top. Okay. And nowhere . Maybe you see it everywhere.

14:38 ? And whatever the whatever that pattern growth tells you indicates what it is

14:43 terms of ero tolerance. Okay um the so then you just look for

14:50 pattern. Right? And so here's look at this question here.

14:56 so here's here's the kind of pattern you would see. Okay, um

15:00 again, the the this represents the , the darker type, either particles

15:08 zone these are the that's the Okay, so we have we have

15:13 bacterial strange each grown on plate medium based on these results, which strain

15:22 super oxide is my taste, has a's and peroxide is okay but expresses

15:31 levels of these or maybe missing one two. Okay, so, I

15:35 this question here here on purpose. . Because the pattern you see,

15:40 me open this up. The pattern see is all dependent really on these

15:47 enzymes. Right. Remember, it not necessarily be all or nothing,

15:52 you may have the enzymes, but may not have the full complement.

15:56 may not have full levels. It . Okay. We may not have

16:01 at all. Right. And that that brings about the particular pattern.

16:07 , so this is asking if you those but they're at less than quote

16:14 levels or maybe missing one or What kind of pattern would you

16:19 Okay. Right timer's on oops. about that? You're not sure.

17:26 okay. This is the purpose of is really to teach you something.

17:33 , let's see. Okay. So um in and on the next

17:46 we evaluate all three of these. so on a. Okay, this

17:52 , would you say that A. has the full complement all three of

17:59 ? Why not? Yeah. Uh not throughout the entire tube. Uh

18:07 is able to withstand oxygen. That's my guess would be a contender

18:15 having all three of these. Because it's right. It's in the

18:19 amount area where the maximum amount of is at. Right maximo to means

18:26 intense in terms of making these Okay, so you better have full

18:34 of these things if you're gonna live this area because you're exposing yourself to

18:39 levels of CO two got to have protection on those conditions. Makes

18:45 Okay. So uh so A is your that's what you are. You're

18:51 . Arabs That's a. Okay. and again, these are described on

18:56 next slide. Um See do you is any of these? Right,

19:04 . So this guy has no He's at the very bottom where there's

19:08 02. It can't withstand any levels 02. So lefty has none of

19:14 protective enzymes. This is your advocate a robe. And I think that's

19:18 opposite of A. This is the anaerobic here. Okay. Um the

19:25 okay so B. And B. . That can be a tricky

19:31 But what you do is again, at the growth pattern and you see

19:37 is the most amount of growth occurring B and D. Okay.

19:43 So if you could just B. D. Okay so we see that

19:49 concentrated up here for B. They grow through aptitude. Okay. It's

19:54 concentrated at be at the top here be okay um than it is in

20:01 . Okay now um B. And . B. I would argue it's

20:08 be like a. It's gonna have it can grow very well at the

20:16 it's most oxygen. So I would guess that it probably has a full

20:20 like A. Does okay because it's to grow fairly well. You compare

20:26 to a. You know it can can withstand the high levels of oxygen

20:31 grow quite well. Okay so Okay is a little different. Okay

20:40 um I I'm not gonna say it it could have the full level,

20:45 you might go well how would you that? Okay, but let's look

20:50 why why D grows throughout top middle alter out just like be what does

20:57 mean that it doesn't grow uh very high at the top as B

21:05 Okay. You what? And so oxygen levels, how does that correlate

21:12 growth? Uh Well I yeah I'm gonna disagree with you. And maybe

21:23 some it can but there is still here. Uh Maybe but it could

21:29 a full complement of those enzymes but more think less now of the protective

21:35 and more now of metabolism. So the oxygen oxygen oxygen metabolism. Because

21:45 don't know this yet. You may it, but we'll learn in a

21:48 of weeks. So oxygen metabolism oxy produces more what than then let's say

21:58 respiration produce more energy. You actually more a tps per per mole of

22:07 used um with an oxygen metabolism than do with what could be anaerobic

22:16 I understand we haven't gone through this but a preview of coming attractions.

22:20 ? So um and so it all to that auction auction at the end

22:25 learn uh that having that's very powerful terms of producing lots of A.

22:31 . P. S. Okay through . Okay. There are anaerobic respiration

22:36 that are almost that good. But as quite. And but it just

22:41 to a lesser level of 80 Production. So the amount of energy

22:45 on the food being eaten by the directly correlates to how much growth can

22:50 . Okay so this be turns out be the faculty native antelope.

22:58 so we can both use oxygen. . And grow with it uses it

23:03 virus and can grow without it. ? Or with various levels of

23:09 Okay, so your e coli e is a faculty of antelope.

23:15 Uh it can grow very well with . It can ferment that doesn't use

23:21 . It can even inspire an Okay so um d is what we

23:28 the aero tolerant and a robe. . And that tends to be the

23:34 one of all five because you go , you see growth throughout. But

23:38 is it not faculty active? you kinda have to compare it to

23:41 faculty of an arab. Okay. that's kind of a clue there.

23:45 . So aero tolerant and Arabs do use oxygen. But they are capable

23:50 living in an oxygen world because they the protection. Okay. And um

23:57 know, I would argue that if don't have the full complement they have

24:01 have close to it, I would because they are growing up here.

24:05 . But they just don't use So they can't get the benefit of

24:09 little more A. T. You get from using oxygen respiration.

24:14 ? So um so D. I would argue is for sure one

24:24 has uh these protective enzymes but not full complement because they're growing in the

24:30 . So they're definitely oxygen there. they can't handle levels up here.

24:36 . And of course they do use oxygen because they're not growing down

24:41 They are not growing down here. , So they can use oxygen.

24:46 just at low levels. These are micro era files. Okay. So

24:53 and and I know um we tend think of the natural world in terms

24:59 humans and what we do, That that what we do is what

25:03 must do in the natural world. . And so we of course are

25:08 . Arabs Okay. We're a but I'd say the microbial world is is

25:15 gonna say evenly divided. But you , it's there's there's lots of micro

25:20 . Lots of faculty two types and tolerant types. B. B.

25:24 . And E. Are probably more in the microbial world than our than

25:28 a. Okay. For sure. , so micro profiles certainly. And

25:36 fermentation is is common the microbial world for sure. Archaea. Um So

25:46 would argue that E would be the for this one. Okay. Is

25:50 any questions about that? Yeah. even though it's a it kind of

26:11 it. Right. Right. That's . So MicroAire fall uses 02 but

26:21 levels like maybe 10 or 5%. 21%. Yeah. Less than

26:26 Okay. Um so let's look at description of these, of these

26:33 Okay. As just mentioned. So different patterns for each and so I

26:39 it down kind of in this A robe and a robe faculty

26:42 Okay, So uh Arabs of course 02. But there are different levels

26:50 of how much they can handle Less than atmospheric levels. Like I

26:56 , it's likely around 105% 02. is average values for that. And

27:04 cannot use 0.2. Okay. So it's not part of their metabolism to

27:08 it. So these can be possibly anaerobic respiration. Um But the

27:17 is that all big and robes don't have those protective enzymes. So it's

27:23 . Oxygen is toxic to them. tolerant. And do have that

27:28 So they can live in the 02 . Okay. Um, but not

27:34 just don't use auction in their Okay. Again, they're typically

27:40 Maybe some of them are anaerobic Okay. And then your faculty of

27:44 . So uh again, all depends where they happen to be and the

27:51 and this oxygen present. Is it ? Is it that certain level?

27:54 have you? Okay. They typically use the oxygen present and just keep

27:59 it until it's gone. And then it's now it's an anaerobic environment.

28:04 they'll continue to grow in that Okay. Um, so, but

28:11 course they have the protective enzymes options toxic to them. Okay.

28:17 What's the next slide? We we just talked about that. Right.

28:22 faculty versus the aero tolerant an Okay. Um, Any questions.

28:35 . Was a little. The two them are not don't don't buy in

28:44 region, but they have to have closer so it doesn't get the

28:51 No auction doesn't kill him says oxygen not toxic, not toxic. So

28:56 doesn't kill they had they had the of the enzymes. It's just that

28:59 guys cannot use oxygen in the so that gives them a little bit

29:02 energy production. So let's growth these it. Okay. Are able to

29:10 0.2. Okay. Anything else? . Um Alright, Lysol. So

29:20 we're getting to the second half of um section we're gonna talk about on

29:25 , antiseptics, sterilization uh sanitation. . So we've all I'm sure seen

29:33 one time or another. Uh Not the Lysol can a can of whatever

29:38 favorite disinfectant is. Um A listing because all these manufacturers of these

29:46 of course, test everybody. Test just doesn't work and what doesn't work

29:51 ? All right, so uh we at these terms here in a second

29:57 exceptions, disinfection, sterilization, all of these all of those lead

30:03 reduction of microbes. Okay, So that it's a matter of how fast

30:11 they killed. Um And what's the the treatment you have to do to

30:19 them to be killed that fast. And then it's of course you're

30:25 all microbial levels are reduced. But course what you're interested in are are

30:29 actively killing pathogens? Right, so of course of interest here. And

30:35 that's why you see a listed commonly they're pretty good. Pretty similar from

30:39 to manufacturer. All kind of test same same target strains. So these

30:43 all um um pathogen type strains. bacterial and fungal salmonella. These are

30:51 all bacterial, there's no fungi in . Um The virus is certainly now

30:57 sure that we got Covid on this from the old labels now. I'm

31:01 that Covid's and all the labels Um But anyway, so the point

31:05 is your these treatments all reduced microbial . But of course you want to

31:10 those pathogens right? Causing infectious And so they all also will have

31:17 kind of data on it. Certainly the top would be it kills 99.9

31:22 99.99 or 99.999% because that's what most are certainly aware of colds and flu

31:42 . Right? Disinfects lots of blah blah blah sanitizer soft surfaces.

31:48 sanitizers more um more of a treatment can do on. So disinfectants can

31:56 be used on items that can like and floors and things like that.

32:00 And so you probably have to dilute as a sanitizing agent. You'd likely

32:04 to dilute this so so it won't your soft surface if you're sanitizing,

32:09 don't know, a pillow or something on a pillow. The full strength

32:13 may maybe too much. So you of can dilute it out somewhat but

32:18 can be additional types of treatments you do with these agents. Um So

32:24 , the point here I wanted to was that 99.9% killed, Right?

32:27 99.99. So you may think well it's down it's practically zero.

32:33 well, we just did a basic here, right, million cells in

32:36 way they test these things on They typically have like a little um

32:40 and metal template that's like two inches . And they'll do the they'll measure

32:46 do a swab inside that area and the levels of bacteria for example,

32:53 are there in that two inch square and then they'll have different areas like

32:57 that they'll test what's actually there, spray the area, apply that is

33:02 in that area and then see how survived. Right. So it's kind

33:06 how they do these things. And if we kill 99.9, you know

33:11 how many are killed. All we're down to 1000 viable cells.

33:16 . So somebody looks at that and goes holy God, we're probably down

33:19 zero almost. Right, well, quite Okay. Um If you start

33:23 even more cells, you know, have even more left after that

33:27 but if you went to um And logs of death, right. What

33:31 getting two logs of death. So 10 represents 10 of the third

33:36 between a million and 1000 3 logs death. Right. So that's really

33:41 is what the manufacturers of these of products. Look at how many logs

33:47 death occur. You know what time ? Some some use the parameter of

33:53 logs of death. You have 12 of death. This is what we

33:56 for our products, blah blah. it can vary. Okay. The

33:59 is we're focused on that. The curve is part of the growth

34:02 Right? How fast can we kill things? Okay, so here's the

34:07 . Right? So you know that use of the word sterilization is my

34:11 my uh get annoyed with people don't it. Right. Okay. So

34:18 let's see what we have here. again, we're not talking in the

34:21 of not being able to have Okay, this is the other meaning

34:26 . Okay. Remember if you think correct, It's okay to say none

34:49 the above or all of the People are so opposed to taking that

34:54 on a test of choosing that On a test. You know,

34:59 could be could be right. Think that. Okay. Okay, let's

35:37 . I bet I bet I know the answer is. Yes. You

35:42 my advice correct? Can see. ? So remember that on the

35:51 it could be that it's all the and on the above. Um

35:57 so it's not patronization. It's not , not acceptance. Although all three

36:01 those can result certain what will result a lowering of numbers, sterilization goes

36:09 zero. Okay. Um so real uh these terms. Okay, and

36:18 think we've done this once before, the top three in the context of

36:23 checker one, I guess it was destruction of all cells for viruses and

36:29 disinfection. And sepsis has to do the application. Um Surface typically versus

36:37 tissues of course differentiates this infection and . Um certainly disinfection and sepsis,

36:44 about pathogens, pathogen pathogen pathogen test being being reduced or their levels being

36:52 of course, because we know all these are going to lower levels of

36:56 , right? But for disinfection and of course we're targeting pathogens.

37:02 so uh the sanitation is a little . So there it really is about

37:08 overall numbers. Okay. Um it to more hygienic practices those of you

37:17 may have worked or maybe still work a restaurant wearing plastic gloves from your

37:24 food hairnet, um making sure services the food prep area are clean the

37:35 clean and it doesn't have food debris it. Um things like that.

37:39 . These are things that will minimize minimize the, you know um incidence

37:46 food borne illnesses right from the So uh and so all this kind

37:52 encompasses what sanitation is using those kind practices to reduce. So certainly you

37:56 clean, you know, in addition doing that, you know, you

38:00 clean the services as well with different of agents to further reduce microbial numbers

38:06 it's not just that practice of cleaning but also the other things you

38:12 Okay to again reduce overall uh numbers numbers of microbes in the environment.

38:20 and you know what is the levels have to be at that's typically determined

38:25 your county uh our city health department department codes. Right. So we

38:32 probably seen at one time or another friday restaurant reports or they go out

38:37 local restaurants and see this thumbs down this one thumbs up on this one

38:42 in my day, it was um who became famous for it here in

38:48 . The Um slime in the ice . Ask your parents about that,

38:54 you heard slime in the ice That's Marvin's similar channel 13 I

38:57 So he made he he started the thing about restaurant reports and whatnot.

39:02 this is what they're checking the sanitary in those restaurants. Okay, so

39:08 google climbing ice machine. See what get. Um Simon dice machines.

39:15 more or less like the sugar snake occurs in the in the piping of

39:20 of the soda fountains. Um Okay terms that we use in describing the

39:31 of these agents, whether it's an disinfectant. What have you, bacteria

39:36 recital bacterial lyric. Okay so um bacteria aesthetic of course is an inhibitory

39:44 killing effect. Okay, so all of these graphs, there's a couple

39:50 we're looking at. One is uh viable cell count. That's the the

39:55 line. Okay. Um that is simply by taking samples from your these

40:02 all gonna be liquid culture. And liquid culture. Then you add whatever

40:07 agent is you're looking at. And and that's indicated by the arrow.

40:11 ? This is the time point at you would add the agent.

40:16 And then um and then you take sample, we take a sample throughout

40:23 dark line and you and you you the sample and you plate them

40:28 It's how you get a total cell in your in your culture.

40:33 And um uh typically expresses a Okay, so um then you

40:39 well, so viable count of like the name says, is the

40:43 of viable cells in your culture. . And so um so if you

40:50 an agent and plateaus, right? plateau mean is not really killing

40:55 Right? It's basically stopping the That's what you get. Now get

40:58 constant number um uh at every time after the addition. So right

41:04 Okay, the total cell count and and this example at least is actually

41:11 a sample and looking under the What am I seeing under the microscope

41:16 time. Right. Obviously pre pre of agent, you're seeing more and

41:22 cells as you look under the Right? You start with a few

41:25 you get a little more and more more and so forth. Right?

41:29 then it's like okay we add the then what happens? Right. Well

41:33 you're seeing visually under the microscope is really changing post edition of chemical or

41:37 it is. Right. And neither the viable count. Right. So

41:41 of the plateau owed no growth is presumably it's been inhibited. Right?

41:46 the nature of a bacterial static Bacterial seidel and bacterial ipic have the

41:53 are the same in terms they kill viable counts go down in both

42:00 Right? You see here here and that bible count line, the dark

42:06 going down after addition. Okay, that's definitely saying it's killing.

42:11 so both of those do that but you can you can kill cells in

42:15 ways. Okay. That's basically what is meant to show here.

42:19 so here we're looking at this is view under the microscope. Okay,

42:26 A. And A. Is coming this one. Yeah bacteria static agent

42:36 B. Is coming from bacterial decay . Okay, so you see the

42:41 numbers are kind of staying the Okay but you're visualizing now you're viable

42:46 going down. Okay. But visually looks the same after addition of agents

42:52 . They're going away. Right. so basically you know you can infer

42:58 from the name right, bacterial politic blowing up the cells right? Both

43:05 killing but one is killing by license . Yeah that again. Uh Only

43:21 microscopy. No, but there are that you can you can use fluorescent

43:29 . Some will that will bind only live cells and not dead ones.

43:34 there is a fluorescent standing technique you use to differentiate if you're only using

43:40 , if you're not then you have verify with the bible cell count.

43:45 . Oops any other cautions. so again basically difference here is you

43:51 kill the cells by just blowing them . Right? And you see him

43:54 away over time or you interfere with like for example something that would disrupt

44:01 cell membrane, right? Would cause to lice but maybe you're just uh

44:08 inhibiting or or somehow affecting protein synthesis may not necessarily have an effect in

44:14 up the cell. But you are it of course. Okay, so

44:17 just depends on the typical the type agent it is. Okay, bottom

44:21 is that both of these are It's just how you're killing it.

44:25 . Um Alright, so one common value used as I mentioned I

44:33 the logs of death. Right, basically decimal reduction time it's the time

44:39 time required to get one log of . That's basically what it is.

44:43 long to get one log of death they call that the D.

44:46 But again other companies have different variations this. Um But in any case

44:54 all the same in terms of logs death. Okay so devalues just one

44:58 of death. So it's very easy come up with this. So we

45:02 a A drop in cell numbers and forget what the actual treatment here is

45:11 exposure in terms of minutes. Okay count. Okay and then we're dropping

45:18 they just pick two points that are log apart and just extrapolate. And

45:24 come up with a D. Value of about one minute. Okay so

45:28 it can vary of course from agent agent. What you're testing? Maybe

45:32 want to test you know more than log. But again the D.

45:36 is specific for one log. So certainly lots of things that can

45:41 , you know if you're applying disinfectant something um lots of things can affect

45:45 . What are the microbial load refers how much, how many microbes are

45:51 ? Is there a lot. Is just sparse and often you are going

45:55 know that um Certainly the concentration of use, how long do you expose

46:03 agent on the surface? For example was a disinfectant. How volatile is

46:09 agent are you using an alcohol Um uh disinfectant versus a maybe a

46:17 base which is funnels are aromatic. they those final based agents tend to

46:22 of stick to the surface and not eyes very quickly. Whereas ethanol alcohol

46:28 ones do. So that's a consideration the longer it's sticking on the

46:31 the more it's acting on the Um the also organic load is another

46:38 . So organic load really refers kind to the cleanliness of what you're applying

46:46 too, which is why many times will say first clean the surface.

46:52 going to disinfect right to reduce the load because we don't, it's really

46:56 dirt and grime already there that's kind absorbing your agent and not really getting

47:01 the microbes that are there. So it's very very common to clean first

47:07 like a just a household cleaner type and then come back with your disinfectant

47:14 makes it more effective. Killing of agents that are there. Okay,

47:20 again, different means will affect um affect how effective the agent may

47:27 And so one thing you won't see that may come close I guess,

47:32 you're not gonna see where a curve this. Okay, that's like all

47:38 over a cliff at once. Because in the population it's gonna be

47:45 . Okay, uh killing a cell really accumulation of damage. Okay enough

47:51 get damaged. Uh cell membrane gets . What have you? A combination

47:56 these things occur that then leads to cell dying right? There can be

48:01 . Micro differences between the cells and population so they won't all die at

48:06 for that reason. Okay especially if if it's very dense you know you

48:13 have cells on the interior that maybe protected somewhat by the number of cells

48:18 them and so that too will affect die later. The other ones on

48:23 periphery will die sooner. So certainly a dense population can affect things as

48:28 that way. So the point is not gonna be something like this is

48:32 be at some rate. Okay. it could be very fast but it's

48:38 be at some slope. Okay. All right the okay so here's a

48:46 on decimal on the values. Okay remember so the values of time it

48:54 you right there. Time to get log of death. Okay so we

48:59 disinfectant. So a culture containing 10 the six cf us per mil

49:05 F. U. Is calling the unit. Think of its cells per

49:09 . Okay and the D. Value two minutes. How many viable

49:15 After eight minutes of exposure. Alright. four seconds counting down.

50:14 2. Okay. D. Is consensus? Let's see uh longer every

50:26 minutes point blank. So D. . Is correct. Okay that wasn't

50:33 don't think I hope that wasn't too . Yeah in this example. Yeah

50:45 that that's it correct? Okay um I'm gonna there's another question I'm gonna

50:54 and come back to it so we get through. So just we'll come

50:58 to that at the end. so let's talk a little bit about

51:04 this is probably you probably figured this on your own if you thought about

51:07 for a few seconds. But what the targets? Well, what's what's

51:12 what's the disinfectant? Antiseptic or Gonna see. Right, Well,

51:17 gonna see stuff on the envelope. , so plasma membrane certainly a target

51:23 the membrane slicing the sell their agents chemical agents that mimic the fossil lipid

51:31 and then can just basically dissolve Um that's really the action of during

51:38 , the 70% disinfectant you spray on bench tops. That's really the action

51:43 has is dissolving the plasma membrane. Other agents can of course destroy proteins

51:50 nucleic acids. And so remember that you know, that's really um if

51:58 obviously affect proteins affect the survival of cell. So you kill the proteins

52:03 makes through the saturation. Remember, proteins have that tertiary structure. Others

52:09 coronary structure on top of that. you unfold it of course the proteins

52:12 function. So chemicals gonna have that , nucleic acids can break as well

52:19 treatments harsh enough radiation high level radiation rays can break nucleic acids. Um

52:29 basically destroying the components of the cell will kill the cell. So um

52:36 temperature methods. Okay, so um sterilization. Okay, so steam under

52:46 creates temps that are very unusual for to be able to withstand.

52:55 you have hyper thermal files, Archaea. But those are going to

53:01 the kind of typical microbes you'd expect see in things you disinfect.

53:05 Unless you're disinfecting a geyser. And that's just insane doing that.

53:10 , um so, you know, talking about things, we treat our

53:16 that live at, you know, temper 37 somewhere. Missile files like

53:20 are, that's the term Missile files in ambient temperatures. Right? So

53:25 so raising it steam under pressure, 221 degrees century. That's that's going

53:30 kill that. And and the steam that moist heat is what can penetrate

53:36 . So that's why steam civilization kills that steam can penetrate those sports and

53:43 it. Okay, the nature of proteins and that's standard 15 P.

53:47 . I. 1 21 15 Sometimes you see 20 minutes, both

53:53 15 or 20 minutes that that those is sufficient. But I was told

53:58 an autoclave technicians basically the first minute the end those spores. But you

54:03 , they do we do overkill and just to make sure. Okay,

54:06 pun intended overkill. Okay, uh let's see. So next.

54:17 , dry heat. So you can equivalent processes. Right? So

54:22 it kind of goes back to what got in the lab to to

54:25 And if you don't have an well, you could use an

54:28 Okay. And achieve the same the result. All you have to do

54:34 for longer. Okay, higher temp longer. 1 70 degrees for

54:39 For two hours. You don't memorize oven condition. You might want to

54:45 the autoclave condition, but what about other ones? Okay, um but

54:51 , so you can have equivalent treatments sterilize? Okay, pasteurization is not

54:57 sterilization but you are reducing numbers, is reserved for food and beverages.

55:04 , Pasteur. Right. The whole contamination problem. So, kind of

55:10 pasteurizing was kind of born out of . We are context is particularly in

55:15 context of milk. Right? But things can be pasteurized as well,

55:20 because you don't want to subject foods other beverages to autoclave conditions. The

55:26 is not going to come out very . Okay. In fact, it

55:29 be horrific. Try to eat something even look at it. Okay,

55:33 it's been through an autoclave, so have to use less harsh treatments,

55:39 the number of microbes still, but the integrity to texture the feel the

55:45 , etcetera of the food. So that's why use pasteurization or other

55:51 . You can filter filter liquids of . So anyway purposes too, preserve

55:58 food itself as well. So you have different pasteurization conditions. Um very

56:05 . Uh more and more so is ultra high temp Also it's it's basically

56:13 same as ultra pasteurization. Okay. are kind of basically the same

56:17 Okay. 130 for they differ only a few degrees in terms of

56:23 but it's still the same one or seconds. Right? So that has

56:27 developed in the last 10 years I . Um But it's been particularly

56:35 22 more of the underdeveloped countries that that can have spotty refrigeration.

56:43 Because an ultra pasteurized ultra pasteurized milk put into a sterilized container. So

56:49 are ultra pasteurized or put in sterile and they can have a shelf life

56:57 like three months unrefrigerated. So that proven quite useful and helpful in

57:05 many areas of the earth. People now get these kind of products and

57:10 sure that it's it's safe. Um also uh the pasteurization of milk

57:20 , there is uh for many of treatments, they look at different types

57:24 target organisms uh to test whether it's know whether it's how how good the

57:30 processes for autoclave ng they actually do a test organism for that. Anybody

57:35 a guess on that. But that would be talked about at the very

57:40 of class today. And those four . So you actually can use like

57:45 bacillus in this four former. There's a test for your autoclave method if

57:49 can't kill the spores after your autoclave . You need to call the service

57:54 come out. Um For milk pasteurization chosen cox C. L.

58:00 This is a it's not an endospore but it's it's the most heat heat

58:05 type that's not an endospore former. so they kind of use that as

58:10 measure of pasteurization success. Okay so Alright cold temp and what else infiltration

58:22 think is on here. So cold is not something that's going to kill

58:28 temps. Refrigerate of course foods and to to prolong until it gets the

58:35 . Can still spoil of course refrigeration it prolongs it right because we're inhibiting

58:39 at these cold temps. Uh we cold temp and lab for preserving

58:44 Whether it's refrigeration temp or -80, very common to keep cells in a

58:50 of suspended animation that we can still them. But it's good for long

58:54 storage. Um Because of course metabolism way down right and of course growth

59:00 way down and so um they will viable for quite some time under those

59:06 now in terms of problematic types of . So when you've seen the listeria

59:13 , the story can grow on food the fridge. Very common for like

59:18 foods like your salamis and bolognese and . Um can can can grow on

59:27 in the fridge. Ok for most have a healthy immune system doesn't really

59:32 you may be slightly upset stomach kind thing but it's something we'll talk about

59:38 at the end and the last part the course, that's one of our

59:41 is listeria. Um The filtration of . So not everything can be

59:48 Right? So in lab we have few media, a couple of media

59:52 you can't put the autoclave to You have to filter sterilize it because

59:56 components are too susceptible to the autoclave just destroys it. So you have

60:00 filter sterilized. There's different beverage I think that you can use filtration

60:06 a way to remove microbes. Um the yeah the heat label, that's

60:14 that heat label or liquids that can't lose their integrity if they are treated

60:21 high temps And so that's where we filtration for those things. Okay,

60:26 technically can't be removed. I think can have filters from a practical usage

60:37 and go down like point 0.1 I think so. But generally viruses

60:44 the context of like making media in lab or other uses viruses aren't generally

60:49 concern. Okay. Until they become . So you don't really kind of

60:53 about that so much. Okay um any questions for radiation is next.

61:03 radiation is used. Okay, remember wavelengths. Right, so electromagnetic spectrum

61:12 you're on the left end. shortly. So wavelength relates to

61:17 Right? So very short wavelength high , longer wavelength, low energy.

61:23 um gamma rays versus radio waves. waves are super long. Very low

61:28 . Okay gamma rays very high Okay UV rays Yes. High energy

61:35 not to the level of gamma Okay so what we call non ionizing

61:42 ionizing radiation UV light. Perfect You realize best for what we call

61:49 disinfection. UV light on the Um Just in fact that it's you

61:58 of course use radiation is not gonna effective on liquids. So radiation is

62:02 on surfaces um and different types of like plastics but they do use um

62:09 we get there. So the difference UV light is you can create

62:13 Okay you don't you don't break N. A. But you can

62:16 mutations in the bases. Okay so can have a lethal effect that

62:20 Okay um The but it's easily Right? You can short can block

62:28 typically uh we used to do in a UV light experiment and you'd have

62:34 expose UV light to a Petri dish bacteria growing on it and the student

62:39 to take the Petri dish lid They wouldn't see any kind of effect

62:43 the lid itself can just stop the light. So it doesn't take a

62:46 to block it. Okay um but radiation like gamma rays. X

62:53 Um These can super high energy. so you see their 0.1 nanometer wavelength

63:00 to 203 104 UV light. So that much higher energy translates into more

63:05 . Okay, and they use radiation on on meat and on frozen

63:14 They use ionizing radiation um and other I think things like uh uh think

63:24 types of plastics and things like that be used sterilized with ionizing radiation.

63:28 it varies it has it has its for sure. Okay, it can

63:33 a sterilizing agent for sure. Certainly radiation. Um Okay. Chemical

63:41 So chemical commercial disinfectants um beta dine the doctor's office. You might see

63:49 wait uh the kind of yellowish um Material that's beta dine. So it

63:58 an island and the island acts as disinfectant. Um phenolic six. These

64:05 proteins typically. Um of course bleach well can damage proteins. So uh

64:13 be quite useful alcohol. Okay, ethanol we use 70% ethanol lab as

64:21 . Um 95% ethanol. Okay. 70 so having a little bit higher

64:28 concentration actually enhances the effect of the . Okay, so 70% ethanol is

64:35 better disinfectant, 95%. The the of water. They're actually helps the

64:42 of the alcohol in dissolving the Right? So I remember uh you

64:48 , sell life with 70% water. so the that little extra amount of

64:53 in your ethanol solution helps helps it better basically by dissolving the membranes.

64:58 , better than 95%. Um And these kind of molecules you see here

65:06 is what's called a short the short is called the quad Q U A

65:12 . And it's short for a co ammonium sulfate salts I believe. And

65:20 these will these mimic the structure of lipids? Okay. Remember fossil lipids

65:27 the polar group on one end and have the fatty acid chains.

65:34 And so which are non polar. so these molecules kind of look like

65:39 right there have a charge group on have our group. Right? It

65:44 be very long hydrophobic. And the that's charged, it's kind of um

65:50 mix in with with membrane lipids and them. Okay, so that's what

65:55 do. Um And then gasses, oxide is a common gas used for

66:03 like sterilizing. Um pipette tips, ? You've probably seen use those in

66:08 before. So boxes pipette tips. think even Petri dishes are sterilized this

66:14 things you see their syringes to being . A lot of these are often

66:19 devices. And so you can sterilize gasses, ethylene oxide um because it

66:25 penetrate fairly well but again you wouldn't to use this. This would be

66:30 using a gas to sterilize a liquid gonna mix obviously. So for these

66:35 of instruments for sure. And it kind of a chain reaction effect.

66:40 , under acidic or basic ph this knock side kind of unfolds and then

66:48 quickly will interact with things like proteins gasses and basically oxidized these molecules causing

66:55 . Okay, so um again, of kind of plastic ware and whatnot

67:00 used to used to sterilize with. um and then of course, um

67:08 the box is coming up and So you're looking at this, can

67:11 become resistant to disinfectants? Okay. you have to think that as we

67:18 earlier, disinfectants have multiple targets, ? Membrane proteins in the cell.

67:24 the gas is perhaps other components. in every disinfectant chemical will attack,

67:32 know, maybe at different um levels different components, Right? Because they

67:39 with them, they're going to have effect better on others than than than

67:44 components maybe. But the point is a microbe to be able to counteract

67:50 of the effects going on. We to have a number of mutations,

67:55 ? We have to occur to be to deal with these different um interaction

68:01 that the chemical is having on Right? It's disrupting a membrane and

68:04 proteins and nucleic acids. It's going have to generate mutations to deal with

68:09 these different aspects of it being Right? And that's very difficult and

68:15 combine that with with, you health care setting. You typically are

68:21 you disinfect on a regular basis of . But then you rotate the type

68:25 disaffected use. Okay. And so in itself also makes it much more

68:30 to become resistant where you can see of resistance to disinfectants can come with

68:37 the concentration. So if you try be cheap about it and say well

68:41 just use twice as much. But lower concentration. Well we'll just cut

68:45 half right now will save us Right? But then you know,

68:49 you're lessening the number of targets to hands. Right? So if you

68:53 the level now, maybe it only one or two things in the

68:58 Right? So now there's a greater that maybe a mutation occurs and it

69:03 counteract the effect of that disinfectant. again, if you don't use it

69:08 the proper levels of concentration levels then you might introduce the probability of becoming

69:16 . Okay. And so antibiotics were aware of resistance to antibiotics of

69:23 But these because antibiotics can be more to resistance because they typically have one

69:30 in a cell, it may attack component of cell wall synthesis or a

69:35 of protein synthesis, what have you a component of getting replication but just

69:40 component. Right. And so it's it's not that difficult for microbes to

69:47 a single mutation and that is enough make it resistant. So it becomes

69:52 probability thing. Okay. But because antibiotics have single targets in what

69:58 attacking. Okay effective but you know not using antibiotics sensibly, that can

70:05 up the scenario where resistance may occur it's all about exposing the bacteria to

70:11 antibiotic and there's antibiotics everywhere. Just a sample of wastewater and test there's

70:17 kinds of antibiotics in there, the we chickens and and counter pumped with

70:23 , right? So they're exposed to all the time, so it's no

70:27 they evolved resistance to these things. , so um and you know,

70:34 talk more about this later, but to real quick snapshot the resistant

70:41 Right? And so you really just strategies, Right? And you can

70:46 talked about a couple of these so you can have evolved an enzyme

70:51 basically just destroy the antibiotic easy, can prevent uh the target side the

71:00 , I can mutate and now it bind the antibiotic. Okay, you

71:05 prevent it from getting into the just pump it out. Okay,

71:10 and so you know kind of easy to become resistant by just changing a

71:15 component here. Okay, so um think, oh, last thing

71:23 face therapy using a fage pages are specific for bacteria. And you can

71:31 a page to be the thing to the bacteria. Okay, that's kind

71:36 in the works right now. And to keep your gut healthy, take

71:41 to keep your good bacteria and they're . Okay. Alright folks, so

71:46 the Chapter five questions are on the and uh see you thursday?

72:01 one of

-
+