Physical Method of Microbial Control

8/16/2019 Physical Method of Microbial Control

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THE CONTROL OFMICROBIALGROWTH


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THE TERMINOLOGY OF MICROBIAL CONTROL

The control of microbial groth i! nece!!ar" in man"

#ractical !it$ation!% li&e' (agric$lt$r

(me)icine

(foo) !cience


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*Control of groth*% a! $!e) here% mean! to #re+ent grothof microorgani!m!,

Thi! control i! e-ecte) in to ba!ic a"!'

B" &illing microorgani!m! or

B" inhibiting the groth of microorgani!m!

CONTROL OF GROWTH


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RATE OF MICROBIAL .EATH


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The e-ecti+ene!! of antimicrobial treatment! )e#en)! on fo$r factor!'

/, N$mber of Organi!m!

The n$mber of organi!m! in the !tarting #o#$lation )etermine! ho long it ta&e! tore)$ce the n$mber of organi!m! to a gi+en le+el at a logarithmic )eath rate,

0, En+ironmental In1$ence!

Organic matter ma" interfere ith heat treatment! an) chemical control agent!,

Heat i! more e-ecti+e at loer #H,

2, Time of E3#o!$re

Chemical agent! re4$ire longer e3#o!$re! to control more re!i!tant organi!m!,

Longer e3#o!$re to loer heat can #ro)$ce the !ame e-ect a! !horter time at higherheat

5, Microbial Characteri!tic!

Microbial !#ecie! an) life c"cle #ha!e! 6en)o!#ore!7 ha+e )i-erent !$!ce#tibilitie! to

#h"!ical an) chemical control!,

RATE OF MICROBIAL .EATH


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Alteration! of Membrane 8ermeabilit"

The !$!ce#tibilit" of the #la!ma membrane i! )$e to it! li#i)an) #rotein com#onent!,Certain chemical control agent!)amage the #la!ma membrane b" altering it! #ermeabilit",

.amage to 8rotein! an) N$cleic Aci)!

9ome microbial control agent! )amage cell$lar #rotein! b"brea&ing h")rogen bon)! an) co+alent bon)!, The!e ma"be !tr$ct$ral #rotein! or en:"me!,Other agent! interfereith .NA an) RNA re#lication an) #rotein !"nthe!i!,

ACTION9 OF MICROBIAL CONTROLAGENT9


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8HY9ICAL METHO. OF MICROBIALCONTROL


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8h"!ical Metho)!;!e) to ControlMicrobial Groth

Heat '

Moi! Heat

8a!te$ri:ation

.r" Heat Filtration

Col) '

Refrigerator

.ee#(free:ing L"o#hili:ation

High 8re!!$re

.e!iccation

O!motic 8re!!$re Ra)iation '

Ioni:ing

Non(ioni:ing


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HEAT

;!$all" $!e) to !terili:e laborator" me)iaan) gla!!are an) ho!#ital in!tr$ment,

Heat a##ear! to &ill microorgani!m b"

)enat$rating their en:"me!,


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THERE ARE 2FACTOR9 TO BECON9I.ERE. IN9TERILI


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Thermal )eath #oint i! the loe!ttem#erat$re! at hich all the microorgani!m

in a #artic$lar li4$i) !$!#en!ion ill be &ille)in /= min$te!,

Thermal )eath time i! the minimal length oftime for all bacteria in a #artic$lar li4$i)

c$lt$re to be &ille) at gi+en tem#erat$re, Both T.8 an) T.T are $!ef$ll g$i)eline! that

in)icate the !e+erit" of treatment re4$ire) to&ill a gi+en #o#$lation of bacteria,


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.ecimal re)$ction time i! a thir) conce#trelate) to bacteria heat re!i!tance,

.RT i! the time% in min$te!% in hich >=? of

a #o#$lation of bacteria at a gi+entem#erat$re ill be &ille),


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MOI9T HEAT TEM8ERAT;RE9

One t"#e of moi!t heat!terili:ation i! boiling,

Reliable !terili:ation ith moi!t

heat re4$ire! tem#erat$re! abo+ethat of boiling ater,

The!e high tem#erat$re are mo!tcommonl" achie+e) b" !team

$n)er #re!!$re in an a$tocla+e,


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A;TOCLA@E

9terili:ation in an a$tocla+e i! the mo!te-ecti+e hen the organi!m! either arecontacte) b" the !team )irectl" or arecontaine) in !mall +ol$me of a4$eo$! li4$i),

;n)er the!e con)ition!%!team at a #re!!$re ofabo$t / #!i 6/0/C7 ill &ill all organi!m! an)their en)o!#ore! in abo$t / min$te!,


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A$tocla+ing i! $!e) to!terili:e c$lt$re me)ia%in!tr$ment!% )re!!ing%intra+eno$! e4$i#ment%a#licator! etc,

In a$tocla+e %boilingtem#erat$re increa!ea! #re!!$re increa!e,

The relation!hi#beteen tem#erat$rean) #re!!$re,


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9terili:ation

time! in thea$tocla+eincl$)e thetime for thecontent! of thecontainer! toreach!teri:ationtem#arat$re!,

For !mallercontainer!% thi!i! onl" min orle!!% b$t for a

>===ml bottle it


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9team $n)er #re!!$re fail! to !terili:e hen the air i! notcom#letel" e3ha$!te),

Thi! can ha##en ith the #remat$re clo!ing of thea$tocla+e! a$tomatic eDector +al+e,

Care !ho$l) be ta&en to a+oi) tra##ing air in the bottomof a )r" container %beca$!e tra##e) air ill not bere#lace) b" !team% hich i! lighter than air,

For e3am#le ' al$mini$m foil i! im#er+io$! to !team an)

!ho$l) not be $!e) to ra# )r" material that are to be!terili:e) #a#er !ho$l) be $!e) in!tea),

9e+eral commerciall" a+ailable metho)! can in)icatehether !terili:ation ha! been achie+e) b" heattreatment,

9ome of the!e are chemical reaction in hich anin)icator change! color hen the #ro#er time! an)tem#erat$re ha+e been reache),


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The e3am#le of!terili:ation in)icator!

The !tri#! if the item ha!been #ro#erl" !terili:e) %the or) NOT a##ear!if the heating ha! been

ina)e4$ate, In the il$!tration% the

in)icator that a!ra##e) ith al$mini$mfoil a! not !terili:e)

beca$!e !tram co$l)nt#enetrate the foil


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8A9TE;RI


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The #a!te$ri:ation ofmil& can be )i+i)e) b"'

High Tem#erat$re9hort Time8a!te$ri:ation

6HT9T7

;ltra High Tem#erat$re

6;HT7


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HIGH TEM8ERAT;RE 9HORT TIME8A9TE;RI


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;LTRA HIGH TEM8ERAT;RE 6;HT7 TREATMENT

;HT i! more $!ef$l in #art! of the orl) hererefrigeration facilitie! are not ala"! a+ailable,

To a+oi) gi+ing mil& a coo&e) ta!te% a ;HT !"!tem i! $!e)in hich the li4$i) mil& ne+er to$che! a !$rface hotter

than the mil& it!elf hile being heate) b" !team, The mil& fall! in a thin Jlm thro$gh a chamber of

!$#erheate) !team an) reache! /5=C in le!! than a!econ), It! i! hel) for 2 !econ)! in a hol)ing t$be thencoole) in a +ac$$m chamber% here the !team 1a!he!

o-, With thi! #roce!!% in le!! than !econ)! the mil&

tem#erat$re ri!e! from 5C to /5=C an) )ro#! bac& to5C ,


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Flaming i! $!e) to e-ecti+el" !terili:e the inoc$lating loo# b"heat the ire to a re) glo,

Thi! #roce)$re ill $!e in man" time! in the microbiolog"

laborator" hen e ant !terili:e inoc$lating loo#!,

A !imilar #rinci#le i! $!e) in incineration% an e-ecti+e a" to!terili:e an) )i!#o!e of contaminate) #a#er c$#!% bag!% an))re!!ing,

Hot air !terili:ation i! +err" e-ecti+e metho)! of !terili:ationb$t re4$ire! tem#erat$re of /= C for abo$t 0 ho$r!, The

item! 6 !$ch a! ' em#t" gla!!are% in!tr$ment!% nee)le!% an)

gla!! !"ringe!7 to be !terili:e) b" thi! #roce)$re are #lace) inan o+en%


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FILTRATION

The mechani!m of Jltration i! !e#aration of bacteria from!$!#en)ing li4$i),

Filtration i! the #a!!age of li4$i) or ga! thro$gh a!creenli&e material ith #ore! !mall eno$gh to retain

microorgani!m, A +ac$$m i! create) in the recei+ing 1a!& air #re!!$re

then force li4$i) thro$gh the Jlter,

Filtration i! $!e) to !terili:e heat(!en!iti+e material!% !$cha! !ome c$lt$re me)ia% en:"m% +accine! an) antibiotic,


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Membrane Jlter! com#o!e) of !$ch !$b!tance! a!cell$lo!e e!ter! or #la!tic #ol"mer!% ha+e become#o#$lar for in)$!tiral an) laboratori$m $!e,The!e

Jlter are onl" =,/ mm thic&, The !#ore! of membraneJlter! incl$)e% for e3am#le =,00(Km an) =,5(Km!i:e!% hich are inten)e) for bacteria,9ome +er"1e3ible bacteria !$ch a! !#irochete!% or the all(le!!m"co#la!ma% ill !ometime! #a!! thro$gh !$ch Jlter,

Filter! are a+ailable ith #ore! a! !mall a! =,/(Kmthi! !i:e that ill retain +ir$!e! an) e+en !ome large#rotein molec$le!,

High(ecienc" #artic$late air 6HE8A7 Jlter! remo+ealmo!t all microorgani!m larger than abo$t =,2 Km in

)iameter,


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LOW TEM8ERAT;RE 6COL.7

The e-ect of lo tem#erat$re on microorgani!m )e#en)!on the #artic$lar microbe an) the inten!it" of thea##lication,

For e3am#le% at tem#erat$re! of or)inar" refrigerator!%the metabolic rate of mo!t microbe! i! !o re)$ce) thatthe" cannot re#ro)$ce or !"nthe!i:e to3in!, In otheror)!% or)inar" refrigeration ha! a bacterio!tatic e-ect,


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/, Tem#erat$re

0, T"#e of Microorgani!m

o Gram(negati+e bacteria are generall" more re!i!tant than gram(#o!iti+e bacteria to )i!infectant! an) anti!e#tic!,

Pseudomonas an) Burkholderia ha+e #orin! in the cell all ith

characteri!tic! that ma&e them re!i!tant to a lot of chemical! an)antibiotic!, The" can act$all" gro in !ome )i!infectant! an)anti!e#tic! )$e to thi! re!i!tance combine) ith the abilit" tometaboli:e !ome $n$!$al molec$le!,

o M"cobacteria% en)o!#ore!% an) #roto:oan c"!t! an)

ooc"!t! are +er" re!i!tant to )i!infectant! an)anti!e#tic!,

MICROBIAL CHARACTERI9TIC AN.MICROBIAL CONTROL


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o Nonen+elo#e) +ir$!e! are generall" more re!i!tant than en+elo#e)+ir$!e! to )i!infectant! an) anti!e#tic!,

Li#i) en+elo#e i! a target for chemical inD$r"

o 8rion! 6infectio$! #rotein! that ca$!e !#ongiform ence#halo#athie!7

re!i!t )i!infection an) a$tocla+ing ( C.C an) WHO no recommen) acombination of !o)i$m h")ro3i)e an) a$tocla+ing at /25 C% altho$ghre!earch ha! !hon that an ho$r !oa& in !o)i$m h")ro3i)e folloe) b"an ho$r of a$tocla+ing at /2 C i! *fairl" e-ecti+e*, 8rotea!e! ha+e been$!e) ith !ome !$cce!! in cleaning !ol$tion! to inacti+ate #rion!,

2,8h"!iological 9tate

Acti+el" groing more !$!ce#tible,

En)o!#ore! lea!t !$!ce#tible,

5, En+ironment

Organic material inhibit! chemical! b" bin)ing them an) can in!$late

microorgani!m! again!t heat,

Physical Method of Microbial Control

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