tCvn

Tiu chun Vit Nam

tcvn 6187-2 : 1996 ISO 9308-2: 1990 (E)

Cht lng nc - Xc nh - Pht hin v m vi khun coliform, vi khun coliform chu nhit v Escherichia coli gi nh Phn 2. phng php nhiu ng ( s c xc sut cao nht )Water quality - Detection and enumeration of organisms thermotolerant coliform organisms and presumptive Escherichia coli Part 2: Multiple tube (most probable number) method

H Ni - 1996

TCVN 6187-2:1996

Li ni u TCVN 6187-2: 1996 hon ton tng ng vi ISO 9308-2: 1990 (E) TCVN 6187-2: 1996 do Tiu ban k thut nc tinh lc TCVN/TC/F9/SC1 thuc Ban k thut tiu chun TCVN/TC/F9 ung bin son, Tng cc Tiu chun- o lng - Cht lng ngh. B Khoa hc, Cng ngh v Mi trng ban hnh.

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TCVN 6187-2:1996

Ti u chun Vit Nam

TCVN 6187-2:1996

Cht lng nc - Xc nh - Pht hin v m vi khun coliform, vi khun coliform chu nhit v Escherichia coli gi nh Phn 2. phng php nhiu ng ( s c xc sut cao nht )Water quality - Detection and enumeration of organisms thermotolerant coliform organisms and presumptive Escherichia coli Part 2: Multiple tube (most probable number) method

1. Phm vi p dng Tiu chun ny quy nh phngphp pht hin v m s lng vi khun coliform, coliform chu nhit v escherichia coli gi nh c trong nc bng cch nui cy trong mt mi trng lng mt h gm nhiu ng nghim v tnh ton "s c xc xut cao nht" ca chng c trong mu th. Phng php ny c th p dng cho mi loi nc, k c cc loi nc c cha mt lng ng k vt cht l lng. Vic la chn cc php th dng pht hin v xc nhn cc vi khun nhm coliform, k c escherichia coli, c th c xem nh l b phn ca mt dy lin tip. Quy m ca vic xc nhn vi mt mu th ring bit no , mt phn tu thuc vo bn cht ca mu nc v phn khc vo nhng l do kim tra. trong thc t, vic xc nh E.coli gi nh trong nc c nu iu 3.3 ca tiu chun ny, thng thng l cung cp mt chng c ca s nhim phn. 2. Tiu chun trch dn ISO 3696:1987 Nc dng cho phng th nghim phn tch. Yu cu k thut v phng php th. ISO 5667 -1: 1980 Cht lng nc - Ly mu. Phn 1: Hng dn xy dng cc phng n ly mu. TCVN 5992: 1995 (ISO 5667 -2 Cht lng nc - Ly mu. Hng dn cc k thut ly mu.

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TCVN 6187-2:1996TCVN 5993: 1995 (ISO 5667 -3 Cht lng nc - Ly mu. Hng dn bo qun v x l mu. ISO 6887:1983 Vi sinh hc - Hng dn chung v chun b cc dch pha long kim tra vi sinh vt. ISO 8199:1983 Cht lng nc -Hng dn chung v m s lng vi sinh vt bng cch nui cy. 3. nh ngha i vi mc ch ca tiu chun ny, p dng cc nh ngha sau: 3.1 Vi khun coliform: L cc sinh vt c kh nng sinh trng hiu kh nhit hoc 350C 0.50C hoc 370C 0.50C trong mt mi trng nui cy c lactoza th lng, km theo vic to thnh axit v sinh kh trong vng 48 h. 3.2 Cc vi khun coliform chu nhit: L cc vi khun coliform nh m t mc 3.1, c cng c tnh ln men trong vng 24 h, nhit 440C 0.250C hoc 44,50C 0.250C. 3.3 Escherichia coli gi nh: L cc vi khun coliform chu nhit nh m t mc 3.2 m cng sinh indol t tryptophan trong vng 24 h, hoc 440C 0.250C hoc 44,50C 0.250C. 4. Nguyn tc Cy cc phn mu th, c pha long hoc khng pha long vo mt dy ng nghim cha mt mi trng nui cy chn lc dng lng c lactoza. Kim tra cc ng th sau 24 h v 48 h nui nhit hoc 350C hoc 370C; cy chuyn tip t mi ng c biu hin c km theo sinh kh vo mt mi trng khng nh chn lc hn v khi mun tm E.coli gi nh cy vo mt mi trng m qua c th quan st thy s to thnh indol. Nui cc mi trng khng nh ny cho ti 48 h nhit hoc 350C hoc 370C pht hin cc vi khun coliform, v 440C trong khong 24 h pht hin cc loi coliform chu nhit v E.coli gi nh. Bng cc bng thng k, tnh ton s xc xut cao nht ca cc dng coliform, coliform chu nhit v E.coli gi nh c th c mt trong 100 ml mu th, t s cc ng th kt qu xc nhn dng tnh.

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TCVN 6187-2:19965. Dch pha long,mi trng nui cy v thuc th 5.1 Cc dng nguyn liu chnh Hy s dng cc thnh phn c cht lng ng nht v cc ho cht thuc loi phn tch pha ch cc mi trng nui cy v thuc th v tun theo cc ch dn cho trong ph lc B. i vi cc thng tin v vic bo qun, xem trong ISO 8199. Mt khc, s dng cc mi trng hon chnh dng kh v theo st cc ch dn ca nh sn xut. pha ch cc m trng, s dng nc ct bng dng c thu tinh hoc nc loi ion, khng cha cc cht c th c ch sinh trng ca vi khun trong cc iu kin th v ph hp vi ISO 3696. 5.2 Dch pha long to nn cc pha long ca mu th, s dng mt trong cc dch pha long c kin ngh ph luc B. Chun b dch pha long theo ch dn cho trong ph lc B. 5.3 Mi trng phn lp S dng mt trong cc mi trng nui cy di y, cc hng dn v chun b mi trng a ra trong ph lc A. 5.3.1 Canh thang lactoza 5.3.2 Canh thang macConkey 5.3.3 Mi tr2)ng glutamat-lactoza-format ci tin2) 5.3.4 Canh thang lauryl- tryptoza (lactoza) 5.4 Mi trng khng nh S dng mt hoc mt s cc mi trng sau: 5.4.1 Cc mi trng kim tra tnh sinh kh; 5.4.1.1 Cc thang lc sng-lactoza (mt) 5.4.1.2 Mi trng EC 5.4.2 mi trng kim tra tnh sinh indol:2) C sn dng thng phm kh "mi trng gutamat ci tin c mui khng". Thng tin ny c a ra vi tnh tin li cho ngi s dng tiu chun ny v khng to nn mt s xc nhn ca tiu chun v sn phm ny.

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TCVN 6187-2:1996Nc trypton. 5.4.3 Mi trng ng n, kim tra c tnh sinh kh v sinh indol: Canh thang tryptoza-mannitol-lauryl c tryptophan. 5.5 Thuc th 5.5.1 Thuc th kovac th indol 5.5.2 Thuc th oxidaza dng cho php th oxidaza. 6. Thit b Cc thit b thng thng ca phng th nghim vi sinh gm c: 6.1 T sy hi nng kh trng kh v mt ni hp p lc. Ngoi cc thit b v trng sn, thit b thu tinh v cc trang b khc cn c kh trng theo ch dn nu trong ISO 8199. 6.2 T m hoc b iu nhit, c th iu chnh c nhit hoc 350C 0.50C, hoc 370C 0.50C. 6.3 T m hoc b iu nhit, c th iu chnh c nhit hoc 440C 0.250C, hoc 44.50C 0.250C. 6.4 pH mt. 7. Ly mu Lymu v chuyn v phng th nghim theo ISO 8199, ISO 5667, TCVN 5992:1995 (ISO 5667-2) v TCVN 5993:1995 (ISO 5667-3). 8. Cch tin hnh 8.1 Chun b mu th v cc mi trng cy chun b mu th, tin hnh pha long mu v cyvo mi trng phn lp cc phn mu th, theo nh cc ch dn cho ISO 8199. i vi cc phn mu th c th tch ln hn 5 ml, s dng cc ng mi trng phn lp nng kp. 8.2 Nui cc ng th

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TCVN 6187-2:1996Nui cc ng mi trng cy mu trong 48 h nhit 350C 0.50C, hoc 370C 0.50C. 8.3 Kim tra cc ng th Kim tra cc ng mu ly sau 18 24 h nui mv coi l c phn ng dng tnh i vi cc ng c biu hin c do vi khun sinh trng v sinh kh bn trong cc ng ln ngc (ng Durham), cng vi vic to thnh axit nu trong mi trng phn lp c cha mt ch th pH. Nui tip trong t ng nhng ng nghim cha c bt k du hiu no hoc mi bin i ni trn v kim tra li chng sau 48 h tm phn ng dng tnh. 8.4 Cc php th khng nh iu quan trng cn lu l cc phn ng dng tnh trong cc ng mi trng phn lp th ch l kt qu gi nh v coliform. Do cn phi tin hnh cc php th xc nhn, tt hn l trn cc chng cy thun khit. 8.4.1 Cy truyn, nui m v kim tra Cy truyn t mi ng mi trng phn lp c kt qu dng tnh vo mt hoc mt s ng mi trng khng nh (5.4) tm tnh sinh kh v sinh indol. Ch thch: - Nu mi trng c ch ti thiu nht (canh thanglactoza) c dng phn lp, thnn cy truyn tip vo c hai trong s cc mi trng khng nh chn lc hn (canh thang lc sng- lactoza (mt) hoc canh thang EC) khng nh.

8.4.1.1 Vi khun coliform khng nh s c mt ca vi khun coliforrm chu nhit, nui mt ng mi trng EC khc (5.4.1) nhit 440C trong 24 h v kim tra tnh sinh kh. khng nh s c mt ca E.coli gi nh cy vo ng trypton (5.4.2) to indol 440C trong vng 24h. Sau thm 0.2 ml 0.3 ml thuc th kovac (5.5.1) vo ng nc trypton ( cy mu): Vic xut hin mt mu sau khi lc nh chng t s c mt ca indol._ Ch thch2. Vic s dng canh thang lauryl-trypo-mannit c tryptophan cho php s hnh thnh indol v sinh kh do E.coli gi nh c th hin trong mt ng n;

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TCVN 6187-2:19963. Vic pht hin E.coli gi nh c xem nh l chng c m bo v s nhim phn. tuy nhin cc php th su hn khng nh E.coli c th phi c tin hnh nu xt thy cn thit (xem 8.5); 4. Khi cy truyn t cc khun lc trn mng lc vo cc ng mi trng khng nh, tt hn cng nn cy ln mt a mi trng thch dinh dng th oxidaza.

8.5 Php th oxidaza Mt vi chng vi khun tm thy trong nc cng c th ph hp vi nh ngha v vi khun coliform hu ht cc mt, nhng chng ch c kh nng sinh kh t lactoza, nhit di 370C m thi. Do chng cho cc kt qu m tnh trong php th khng nh chun i vi vi khun coliform v s hin din ca chng trong nc th thng thng khng c coi l ng k. Cc chng aeromonas, xut hin mt cch t nhin trong nc, gy nhiu cho vic xc nh ch nhit 370C v thp hn, vic khng nh bng php th oxidaza ch cn n khi xc nh coliform. 8.5.1 Tin hnh php th oxidaza vi cc ging cy thun khit t cc vi khun ln men lactoza, mc trn mi trng thch dinh dng, nh sau: - nh 2 hoc 3 git thuc th oxidaza (5.5.2) mi c chun b ln mt mig giy lc trong mt a Petri; - bng que cy thu tinh, tm bng hoc que cy c dy bch kim (khng phi loi Nicrom), dn mng mt t mu cy ln trn giy lc c chun b sn (xem ch thch 4). - quan st thy xut hin mt mu xanh-tm sm trong vng 10 giy l phn ng dng tnh. Ch thch - Trong mi trng hp s dng thuc th oxidaza cn thc hin cc php th kim travi mu cy mt loi vi khun cho phn ng dng tnh v mt loi cho phn ng m tnh (E.coli) bit trc.

9. Biu th kt qu T s ng mi trng phn lp v cc php th khng nh cho cc kt qu dng tnh, tnh ton, bng cch tham kho cc bng tra thng k trong ISO 8199, s xc xut cao nht ca vi khun coliform chu nhit v E.coli gi nh c trong 100 ml mu th. 10 Bo co kt qu Bo co kt qu gm nhng thng tin sau:

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TCVN 6187-2:1996a) tham kho tiu chun ny. b) mi chi tit cn thit nhn bit y v mu th. c) k thut v mi trng phn lp dng. d) cc mi trng v cc php th khng nh dng. e) thi gian, nhit v cc iu kin nui cy. f) cc kt qu trnh by ph hp vi iu 9. g) bt k mt thng tin no khc lin quan ti phng php.

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TCVN 6187-2:1996Ph lc A (Tham kho) Thng tin su hn v vi sinh hc lin quan ti kim tra nc i vi nhm vi khun coliform i vi cc mc ch kim tra nc hng ngy, nhm vi khun coliform c th c mt bng cc thut ng vi sinh chung, khng mang tnh phn loi hc, nh sau: Cc vi khun coliform l cc vi khun hnh que (dng thng), gram m, khng c bo t, oxidaza m tnh; chng c kh nng sinh trng hiu kh v k kh khng bt buc trong s c mt ca mui mt (hoc cc yu t tc ng b mt khc c c tnh c ch sinh trng tngt). Chngcng c th ln men lactoza v (mannit) km theo to thnh axit, kh v andehyt trong vng 48 h, khi nui cy nhit 350C n 370C. Cc vi khun coliform chu nhit l cc vi khun coliform cho thy c cng kh nng ln men v cc c tnh sinh ho khi nui cy nhit 440C n 44.50C. E.coli gi nh l cc vi khun coliform chu nhit, chng cng c kh nng sinh indol t tryptophan. E.coli c th c xem l E.coli gi nh, chng cng c mt kt qu dngtnh trong php th metyl v c th loi cacboxyl ca axit glutamic, nhng chng khng c kh nng to ra metyl axetyl cacbonol, s dng xitrat nh ngun cacbon duy nht, hoc sinh trng trong canh thang kali xyanua (KCN).

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TCVN 6187-2:1996Ph lc B (Than kho) Cc mi trng nui cy, thuc th v nc pha long Mi trng phn lp - Canh thang lactoza Mi trng nng kp: Pepton 10 g Lactoza 10 g Cao tht b 6 g Nc ct 1000 ml Ho tan cc thnh phn trn trong nc si. Nu cn, chnh pH sao cho khi kh trng pH = 6.9 0.2. Pha ch mi trng nng n bng cch pha long mi trng nng kp vi mt th tch nc ct tng ng. - Canh thang MacConkey Mi trng nng kp: Mui mt 10 g Pepton 40 g Lactoza 20 g Natri clorua 10 g Bromo cresol (hoc Cresol) ta dung dch 1% (th tch/ th tch) pha long trong etanol 2 ml Nc ct 1000 ml

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TCVN 6187-2:1996Ho tan pepton, natri clorua v mui mt trong nc bng cchun nng v gi 40C qua m. em lc khi dung dch vn cn lnh, b sung lactoza v ho tan. Chnh pH n 7,4 0.2 v b sung bromocresol ta. Mi trng nng n: Chun b mi trng nng n bng cch pha long mi trng nng kp vi mt th tch nc ct tng ng, hoc c th lm ring bng cch gim mt na lng cc cht trong thnh phn. Phn phi mi trng nng n thnh cc lng 5 ml/mt ng v mi trng nng kp thnh tng lng 10 ml v 50 ml. Mi ng nghim hoc l thu tinh c dng cn c mang mt ng ln men ln ngc (durham). Hp p lc 1500C trong 10 pht. - Mi trng format-lactoza-glutamat ci tin3) Mi trng nng kp: Lactoza 20 g L (+) Mui natri glutamat 12.7 g L (+) Arginin monohidro clorua 0.048 g L (-) Aspartic axit 0.04 g L (-) Xystin 0.04 g Natri format 0.5 g Dikali hidro photphat 1.8 g Amoni clorua 5 g Magie sunfat (MgSO4.7H2O) 0.02 g Canxi clorua(CaCl2.2H2O) 0.02 g Vy st(III) Xitrat 0.02 g Thiamin(aneurin hidroclorua) 0.002 g Axit nicotic 0.002 g Axit Pantotenic 0.002 g Bromocressol ta { dung dch 1%(khi lng/khi lng) trong cn etanol} 2 ml Nc ct 1000 ml

Tin li hn c, nn chun b mi trng ny vi lng l 10 lit hoc nhiu hn. Nu nh khng phn phi ngay vo cc ng nghim, th lactoza v thiamin ngoi, khng pha, vag b sung chng ngay trc khi phn phi. cho tin hn, mt vi thnh phn c b

3)

C bn sn dng kh "mi trng glutamat iu chnh khong". Cng c th cn iu chnh PH

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TCVN 6187-2:1996sung vo mi trng dng cc dung dch ring r v cc dung dch na s c chun b nh sau: Dung dch 1: L (+) Arginin monohidro clorua 0.4 g L (-) Aspartic axit 0.48 g Nc ct 50 ml un nng ho tan hon ton. Dung dch 2: L (-) Xystin 0.4 g Natri hidroxit (5mol/l) 10 g Nc ct 90 ml un nng ho tan. 3) C bn sn dng kh ''mi trng glutamat iu chnh khong". Cng c th cn iu chnh pH. Dung dch 3: Axit nicotic 0.02 g Axit Pantotenic 0.02 g Nc ct 5 ml Ho tan m khng un nng. Dung dch 4: Vy st(III) Xitrat 0.2 g Nc ct 10 ml un nng ho tan. Dung dch 5:

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TCVN 6187-2:1996Canxi clorua(CaCl2.2H2O) 2 g Nc ct 100 ml Axit clohtdric m c 0.1 ml Ho tan khng cn un nng, v kh trng 1210C trong 20 pht. Bo qun lm dung dch gc. Dung dch 6: Kh trng dung dch thiamin 0.1% trong nc ct. Tt nht, nn pha ch dung dch ny bng cch: Thm lng cha trong mt ng ampul (100 ml), mt cch v trng, vo 99 ml vo nc ct v trng. Bo qun dung dch 40C v loi b sau 6 tun l. chun b 10 lit mi trng nng kp, ho tan cc lng tng ng ca L (+) mui natri glutamat, natri focmat, dikali hidro photphat, amoni clorua v magie sunphat trong 9 lit nc ct nng. Sau b sung ton b cc dung dch 1, 2, 4, v 4 ml ca dung dch 5. Chnh pH ti 6.8 hoc cao hn nu thy cn thit, sao cho pH cui cng, sau khi hon chnh v kh trng mi trng, l 6.7. Nu dng cng loi thit b v phng php kh trng, th s c cng mt s thay i v pH lun xy ra trong qu trnh kh trng. C th cn n mt vi php th s b to c pH chnh xc trc khi kh trng. Sau khi chnh pH, thm 20 ml dung dch bromo cresol ta 1% etanol vikhong 810 ml nc ct, b sung cho n th tch cui cng l 10 lit. Nu lng mi trng ny khng cn s dng ngay, cho vo cc chai dung tch 500 ml v em hp p lc 1150C trong 10 pht. Khi dng n, b sung lng cn thit cho dung dch lactoza v thiamin (dung dch 6), cho tan u v sau phn phi thnh tng lng 10 ml v 50 ml. Mi ng nghim v l c s dng cn mang mt ng ln men ln ngc (ng durham). iu quan trng l cn bo m sau khi hp v trc khi s dng, ng Durham ny cha y mi trng. Nu khng s to nn mt kt qu dng tnh gi mo v tnh sinh kh. Kh trng nhit 1150C trong 10 pht hoc t vo mt ni hi nc 1000C trong 3 ngy, mi ngy 30 pht. Mi trng nng n: Chun b mi trng nng n bng cch pha long mi trng nng kp vi mt th tch mc ct tng ng v phn phi thnh tng lng 5ml/ng nghim c cha ng ln men ln ngc (Durham). Kh trng nhit 1150C trong 10 pht, hoc trong lung hi nc si 1000C trong 3 ngy lin tip, mi ngy 30 pht.

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TCVN 6187-2:1996Ch thch 6 - Vic b sung 0.1% casein thu phn axit khng c vitamin c th cho cc kt qunhanh hn. - Canh thang lauryl tryptoza (lactoza)

Mi trng nng kp: Tryptoza 40 g Lactoza 10 g Natri clorua 10 g Dikali hidrophotphat 5.5 g Kali dihidrophotphat 5.5 g Natri lauryl sunphat, tinh khit cao 0.2 g Nc ct 1000 ml Cho tryptoza, natri clorua, lactoza v mui photphat vo nc v un nng ho tan. B sung natri lauryl sunphat v trn nh nhng trnh si bt. Chnh pH n 6.8 0.2. Chun b mi trng nng n bng cch pha long mi trng nng kp vi mt th tch nc ct tng ng. Phn phi mi trng nng n thnh tng lng 5 ml, v mi trng nng kp thnh tng lng 10 ml v 50 ml. Mi ng nghim hi\oc l nh c s dng cn phi c mt ng ln men ln ngc. Hp p lc 1150C trong 10 pht. Cc mi trng khng nh - Canh thang lactoza - lc sng (mt)4) ( kim tra tnh sinh kh) 4) Mi trng ny khng phi lun lun cho cc kt qu lp li c, v nn kim tra cc c tnh ca n trc khi dng. Pepton 20 g Lactoza 10 g

Mi trng ny khng phi lun lun cho cc kt qu lp li c v nn kim tra cc c tnh c ch ca n trc khi dng.

4)

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TCVN 6187-2:1996Mt b (kh) 20 g Lc sng (dung dch 0.1% khi lng dung dch nc) 13 ml Nc ct 1000 ml Ho tan pepton trong 500 ml nc ct. B sung 20 g mt b kh ho tan trong 200 ml nc ct. Dung dch ny cn c ph khong 7.0 n 7.5. Dng nc ct a th tch dung dch ln 975 ml. Thm lactoza v chnh pH n7.4. Thm dung dich lc sng v a th tch chng ln n 1000 ml bng nc ct. Phn phi vo cc ng nghim c ng ln men ln ngc (ng Durham), mi ng 5 ml, v hp 1150C trong 10 pht. - Mi trng EC ( kim ta tnh sinh kh) Tryptoza hoc tryticaza 20 g Lactoza 5 g Hn hp mui mt s 1.5 g Dikali hidropho 2HPO4) 4 g Kali dihidro photphat (KH2PO4) 1.5 g Natri clorua (NaCl) 5 g Nc ct 1000 ml pH phi l 6.9 sau khi kh trng. Trc khi kh trng, phn phi vo cc ng nghim vi cc lng ngp trn ng ln men (Durham) ln ngc, t nht ngp phn no sau khi kh trng. - Nc trypton ( th phn ng indol) Mt vi loi pepton cho cc kt qu tt vi cc php th 350C n 370C th li khng tho mn vi php th indol 440C. Ngi ta thy tryptol tho mn iu v kin ngh dng n. Trypton 20 g

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TCVN 6187-2:1996Natri clorua 5 g Nc ct 1000 ml Ho tan cc thnh phn trn trong nc v chnh pH n 7.5. Phn phi vo tng lng 5 ml v hp 1150C trong 10 pht. Ch thch 7 - Vic b sung 0.1% (khi lng m/m) L hoc DL tryptophan ca th ci thin tnhnng ca mi trng.

- Canh thang Lauryl -trypto-mannit c tryptophan (Mi trng ng n kim tra c hai c tnh: sinh kh v sinh indol) Tryptoza 20 g Natri clorua 5 g Mannitol 5 g Dikali hidropho 2HPO4) 2.75 g Kali dihidro photphat (KH2PO4) 2.75 g Natri lauryl sunphat 0.1 g L (-) Tryptophan 0.2 g Nc ct 1000 ml Cho tryptoza, natri clorua, mannitol, cc mui phot pht v tryptophan vo nc v hm nng nh ho tan. B sung natri lauryl sunphat v trn nh nhng trnh si bt. Chnh pH ti 6.8 0.2. Phn phi vo cc ng nghim c cha ng ln men ln ngc (Durham) trong mi ng 5 ml. Hp 1150C trong 10 pht. Cc thuc th Thuc th kovac v tnh sinh indol: P- dimethylamino 5 g Cn amylic 75 ml Axit clohidric ( = 1.18 g/l) 25 ml

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TCVN 6187-2:1996Ho tan andehyt ni trn trong cn amylic. Cn thn b sung axit c vo. Trnh nh sng v bo qun 40C. Ch thch 8 - Thuc th ny cn phi c mu vng nht n nu nht; mt vi mu cn amylic khng tho mn c v cho mu ti vi andehyt. - Thuc th oxidaza Tetramethyl -p -phenylen diamin hidro clorua 0.1 g Nc ct 10 ml Thuc th ny khng gi c v do cn phi c pha ch mi lng nh cho mi ln s dng nu cn n n. Dch pha long - Nc pepton (0.1%) Pepton 1.0 g Nc ct 1000 g Ho tan pepton trong khong 950 ml nc. Chnh pH bng dung dch NaOH hoc HCl (1 mol/l), sao cho sau khi kh trng pH l 7.0 0.1. Thm nc ct cho 1000 ml, phn phi thnh cc lng ph hp v kh trng 1210C 10C trong 15 pht. - Dung dch pepton mui: Pepton 1.0 g Natri clorua (NaCl) 8.5 g Nc ct 1000 ml Ho tan cc thnh phn trn trong khong 950 ml nc bng nc un si. Chnh pH bng dung dch NaOH hoc HCl (1 mol/l), sao cho sau khi kh trng pH l 7.0 0.1. Thm nc ct cho 1000 ml, phn phi thnh cc lng ph hp v hp 1210C 10C trong 15 pht. - Dung dch Ringer- nng mt phn t Natri clorua (NaCl) 2.25 g

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TCVN 6187-2:1996Kali clorua (KCl) 0.105 g Canxi clorua, khan 0.12 g Natri hidro cacbonat 0.05 g Nc ct 1000 ml Ho tan cc thnh phn trn v phn phi thnh cc lng ph hp. Kh trng bng cch hp p lc 1210C 10C trong 15 pht. pH cui cng phi l 7.0 0.1. - Dung dch m photphat Kali hidro photphat (KH2PO4) 42.5 mg Magie clorua (MgCl2) 190 mg Nc ct 1000 ml Cch pha ch: a) dung dch photphat: Ho tan 34 g mui photphat trong 500 ml nc ct. Chnh pH ti 7.2 0.5 bng dung dch NaOH (1 mol/l) v thm nc ct n 1000 ml b) dung dch magie clorua: Ho tan 38 g magie clorua trong 1000 ml nc ct. Dung dch cui cng. s dng, thm 1.25 ml dung dch photphat a) v 5.0 ml dung dch magie clorua b) vo 1000 ml ncct. Phn phi thnh cc lng ph hpv kh trng bng cch hp p lc 1210C 10C trong 15 pht. pH cui cng phi l 7.0 0.1. Mi trng thch dinh dng: Cao tht 1.0 g Pepton 1.0 g Natri clorua 5 g

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TCVN 6187-2:1996Thch 15 g Cho cc thnh phn trn vo nc v un nng ho tan. Chnh pH ti khong 8.2 bng NaOH (1 mol/l), v un si trong 10 pht. Lm trongbng cch lc v chnh pH ti 7.2 n 7.4. Phn phi vo cc l dung tch 100 ml v hp 1210C 10C trong 15 pht.

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