c. perfringens

Hc vin: Nguyn Quc KhnhNguyn Th Oanh KiuTrn Th Diu Hng

Kl c trng,Kt mu en sinh kh trong LSQt ly mu v bo qun k trong qt bo qun mt

Vi sinh vt trong thc phm v thc n gia sc Phng php m Clostridium perfringens -K thut m khun lc1. Phm viTiu chun quc t m t mt phng php m Clostridium perfringens. N c p dng cho cc sn phm dnh cho ngi v cc thc n gia sc, v cc mu mi trng trong khu vc sn xut thc phm v x l thc phm.2. Tiu chunCc ti liu vin dn sau y l khng th thiu i vi vic p dng tiu chun ny. i vi cc ti liu ghi ngy ban hnh th ch p dng bn c nu. i vi ti liu vin dn khng ghi ngy thng th p dng phin bn mi nht (bao gm cc sa i)..ISO 6887-2, Vi sinh vt trong thc phm v thc n gia sc - Chun b mu th, huyn ph ban u v dung dch pha long thp phn kim tra vi sinh - Phn 2: quy nh c th cho vic chun b tht v sn phm thtISO 6887-3, Vi sinh vt trong thc phm v thc n gia sc - Chun b mu th, huyn ph ban u v dung dch pha long thp phn kim tra vi sinh - Phn 3: quy nh c th cho vic chun b ca c v sn phm thy snISO 6887-4, Vi sinh vt trong thc phm v thc n gia sc - Chun b mu th, huyn ph ban u v dung dch pha long thp phn kim tra vi sinh - Phn 4: quy nh c th cho vic chun b cc sn phm khc ngoi sa v cc sn phm sa, tht v sn phm tht, c v cc sn phm thy snISO 7218, Vi sinh vt trong thc phm v thc n gia sc - Quy trnh chung cho cc bc kim tra vi sinhISO 8261, Sa v sn phm sa - Hng dn chung v chun b mu th, huyn ph ban u v dung dch pha long thp phn kim tra vi sinhISO / TS 11133-1, Vi sinh vt trong thc phm v thc n gia sc - Hng dn v vic chun b v v to ra mi trng nui cy - Phn 1: Hng dn chung v m bo cht lng cho vic chun b mi trng nui cy trong phng th nghimISO / TS 11133-2: 2003, Vi sinh vt trong thc phm v thc n gia sc - Hng dn v chun b v to ra mi trng nui cy - Phn 2: Cc hng dn thc hnh v th hiu nng ca mi trng nui cy.3. Thut ng v nh nghai vi cc mc ch ca ti liu ny, cc t ng v nh ngha sau y c p dng.3.1 Clostridium perfringensC. perfringens: vi khun hnh thnh khun lc c trng (kt ta mu en m mu sc cc khun lcen) trong ccmi trng chn lc, v cho cc phn ng dng tnh khi thc hin theo mt trong hai k thut c quy nh trong tiu chun ny3.2 m C. perfringensXc nh s lng hin hu v khng nh vi khun Clostridium perfringens trong mt ml hoc mi gram ca mu khi vic kim tra c thc hin theo phng thc quy nh trong tiu chun ny4. Nguyn tc4.1 a petri c cy vi mt s lng nht nh cc mu kim tra nu sn phm ban u l cht lng, hoc mt s lng quy nh ca huyn ph ban u trong trng hp ca cc sn phm khc.Chun b cc a khc trong cng iu kin, s dng cc dung dch pha long thp phn ca mu th hoc ca dch huyn ph ban uMt mi trng chn lc c thm vo (k thut a) v sau ph mt lp ca cng mt mi trng.4.2 Cc a c k kh 370C trong 20 h.4.3 m cc khun lc c trng.4.4 Tnh s khun lc c trng ca C. perfringens c trong mt ml hoc mi gram ca mu c tnh ton.5. Pha long, mi trng nui cy v thuc thXem ISO 7218 v ISO 11133-2 v cho th nghim chun b, sn xut v th hiu nng ca mi trng nui cy .5.1 Pha longXem ISO 6887-1 v tiu chun c th i vi cc sn phm c kim tra.5.2 Agar-cycloserine sulfit (SC)Lu iu ny ban u c ch nh "lng trng-khng TSC" (xem [1).5.2.1 Mi trng c bn5.2.1.1 Thnh phnEnzyme tiu ha ca casein 15,0 gEnzyme tiu ha ca u nnh 5,0 gCao nm men 5,0 gDisodium disulfite (Na2S2O5), khan 1,0 gAmmoni st (III) citratea (C6H9FeNO7) 1,0 gAgar 9,0 g n 18,0 gbNc 1000 mla :Thuc th ny nn cha t nht 15% (phn khi lng) ca st.b: Ty thuc vo cng gel ca agar.

5.2.1.2 Chun bHa tan cc thnh phn trong nc bng cch un si. iu chnh pH sao cho sau khi kh trng n s l 7,6 0,2 ti 250C. Cho mi trng vo cc dng c v nhng bnh c dung tch ph hp. Kh trng trong 15 pht 1210C. Lu tr trong t lnh 30C 20C. Vt b khi khng s dng trung bnh 2 tun sau khi chun b.Trong mt s trng hp (xem 9.4.3.1), c th cn chun b cc a ca mi trng thch SC c bn khng nh vi mi trng di ng ca nitrat (5.5) v mi trng ng lactose gelatin (5.8). Vi mc ch ny, khong 15 ml ca mi trng c bn [ c lm tan chy v lm ngui gi nhit khong 440C n 470C bng ni chng cch thy (6.10)] vo a petri v ng tr li. Ngay trc khi s dng, lm kh cc a mi trng (xem ISO 7218).5.2.2 Dung dch D-Cycloserine5.2.2.1 Thnh phnD-Cycloserinea 4,0 gNc 100 mla : S dng duy nht bt tinh th mu trng.5.2.2.2 Chun bHa tan D-Cycloserine trong nc v kh trng bng cch lc.Bo qun trong t lnh 30C 20C khng qu 4 tun.5.2.3 Mi trng hon chnhNgay trc khi s dng trong phng php da (xem 9.2), c mi 100 ml ca mi trng c bn kh trng (5.2.1) lm ngui t 440C n 470C th thm 1ml dung dch D-Cycloserine (5.2.2).5.2.4 Th nghim hiu sut cho vic bo m cht lng ca mi trng SCi vi xc nh nng sut v tnh chn lc, tham kho ISO / TS 11133-1. kim tra hiu sut, tham kho ISO / TS 11133-2: 2003, Bng B.1 [xem TS(C)].5.3 Mi trng thioglycollate lng5.3.1 Thnh phnEnzyme tiu ha ca casein 15,0 gL-Cystine 0,5 gD-Glucose 5,5 gCao nm men 5,0 gNatri clorua 2,5 gNatri thioglycollate (mercaptoacetate) 0,5 gAgar 0,5 g n 2,0 gaResazurin 0,001 gNc 1000 mla :Ty thuc vo cng gel ca agar.5.3.2 Chun bHa tan cc thnh phn trong nc bng cch un si. iu chnh pH sao cho sau khi kh trng n s l 7,10,2 ti 20C.Pha 10 ml vo ng nghim v kh trng 1210C trong 15 pht.Trc khi s dng, mi trng ny s c loi b kh.5.3.3 Hiu sut th nghim cho vic bo m cht lng nc dng thioglycolatei vi xc nh nng sut v tnh chn lc, tham kho ISO / TS 11133-1. kim tra hiu sut, tham kho ISO / TS 11133-2: 2003, Bng B.4.5.4 Mi trng Lactose sulfite (LS) (ty chn)5.4.1 Mi trng c bn5.4.1.1 Thnh phn Enzyme tiu ha ca casein 5,0 gCao nm men 2,5 gNatri clorua 2,5 gLactose 10 gL-Cysteine hydrochloride 0,3 gNc 1000 ml5.4.1.2 Chun bHa tan cc thnh phn trong nc bng cch un si (nu cn thit). iu chnh pH sao cho sau khi kh trng t 7,10,2 250C.Chia 8 ml vo ng nghim vi ng Durham ngc (6.7) v kh trng 1210C trong 15 pht.Cc mi trng c th c bo qun 30C 20C cho n 4 tun.5.4.2 Dung dch Disodium disulfite5.4.2.1 Thnh phnDisodium disulfite (Na2 S2 O5), khan 1,2 gNc 100 ml5.4.2.2 Chun bHa tan disulfite disodium trong nc v kh trng bng cch lc.S dng cc Dung dch trong vng 1 ngy.5.4.3 Amoni st (III), dung dch citrate5.4.3.1 Thnh phnAmoni st (III) citrate 1 gNc 100 ml5.4.3.2 Chun bHa tan amoni st (III) citrate trong nc v kh trng bng cch lc.S dng cc Dung dch trong vng 1 ngy.5.4.4 Mi trng hon chnhNu mi trng khng c s dng vo cc ngy chun b, ch cn loi kh trong mi trng bng nhit v sau lm mt nhanh chng. Nu mi trng l trong chai c np vn, ni lng np trc khi nung nng v tht cht chng trc khi lm mt.Sau , thm 0,5 ml dung dch disodium disulfite (5.4.2) v 0,5 ml dung dch st (III) amoni citrate (5.4.3) cho mi 8ml mi trng c bn (5.4.1).Mi trng hon chnh ch s dng trong ngy.5.5 Mi trng di ng Nitrate (ty chn) (MN)5.5.1 Thnh phnEnzyme tiu ha ca casein 5,0 gCao tht 3,0 gGalactose 5,0 gGlycerol 5,0 gKali nitrat (KNO3) 1,0 gDisodium hydrogen orthophosphate (Na2 HPO4) 2,5 gAgar 1,0 g n 5,0 gaNc 1000 mla : Ty thuc vo cng gel ca agar.

5.5.2 Chun bHa tan cc thnh phn trong nc bng cch un si. iu chnh pH n s l 7,30,2 250C sau khi kh trng.Cho 10ml mi trng vo ng nghim v tit trng 1210C trong 15 pht. Nu khng s dng trong ngy, bo qun trong t lnh 30C 20C. Ch cn trc khi s dng, chng trong nc un si khong 15 pht v sau ngui nhanh n nhit nui cy.Vt b mi trng chun b sau 4 tun khng s dng.5.6 Thuc th pht hin Nitrite (khng bt buc)5.6.1 Dung dch 5-amino-2-naphthalenesulfonic acid (5-2-ANSA) Ha tan 0,1 g 5-2-ANSA trong 100 ml dung dch 15% (khi lng phn s) dung dch acid acetic. Lc qua mt b lc giy.Bo qun trong chai ti mu c nt 30C20C.5.6.2 Dung dch acid sulfanilicHa tan 0,4 g acid sulfanilic trong 100 ml dung dch 15% (th tch) dung dch acid acetic. Lc qua mt b lc giy.Bo qun trong chai ti mu c nt 30C20C.5.6.3 Chun b thuc th hon chnhTrn mt lng bng nhau ca hai dung dch (5.6.1 v 5.6.2) ngay trc khi s dng. B thuc th nu khng s dng.5,7 Bt km (ty chn)

5,8 Mi trng Lactose-gelatin (khng bt buc) LG5.8.1 Thnh phnEnzyme tiu ha ca casein 15,0 gCao nm men 10,0 gLactose 10,0 gGelatin 120,0 gPhenol 0,05 g Nc 1000 ml5.8.2 Chun bHa tan cc thnh phn, tr lactose v phenol , trong nc. iu chnh pH sao cho sau khi kh trng t 7,50,2 250C.Thm lactose v phenol , pha 10 ml vo ng nghim, kh trng 121C trong 15 pht. Nu khng c s dng trong cng mt ngy, lu tr trong t lnh 3C2C.Ch cn trc khi s dng, chng trong nc si hoc hi nc trong 15 pht, sau lm ngui nhanh chng n nhit nui cyVt b mi trng chun b sau 3 tun khng s dng.6. Thit b v dng c thy tinh6.1. Thit b sy v trng hoc lm m v trngXem ISO 7218.6.2. T m, c kh nng nui cy 370C 10C6.3. Bnh ln men ym kh, hoc bt k dng c thch hp khc cho nui cy k kh.6.4. My o pH, c kh nng c gi tr pH 0,01 gn nht ti 25C, cho php o c chnh xc n 0,1 n v pH.6.5. Que cy vng, Platinium-iridium hoc niken-crm, ng knh khong 3 mm, v que c hnh kim6.6. Thit b lc, dnh cho kh trng dung dch.6.7. ng nghim, bnh ln hoc bnh tam gic , dung tch ph hp, ring ng nghim vi ng Durham ngc c kch thc l 16 x 160 mm, chiu di ng nghim l 35 mm v ng knh 7 mm.6.8. Pipet c chia hoc micropipet, dung tch danh ngha 1 ml v 10 ml, c chia trong khong 0,1 ml v 0,5 ml6.9. a petri bng thy tinh hoc nha, ng knh 90 mm n 100 mm.6.10. Ni chng cch thy (b n nhit) hoc thit b tng t, c kh nng c duy tr nhit t 44C n 47C, v 46C 0,5C.6.11. ng bp cao su7. Ly muPhng php ly mu khng c quy nh trong quy chun quc t. Nu khng c quy nh c th v phng php ly mu th c s tha thun gia cc bn lin quan.iu quan trng l cc phng th nghim nhn c mt mu thc s i din v khng b h hng hoc b thay i trong qu trnh vn chuyn, bo qun.8. Chun b mu thChun b mu th nghim theo ISO 6887-2, ISO 6887-3 hoc ISO 6887-4, hoc ISO 8261.9. Cch tin hnh9.1. Kim tra tng phn, huyn ph ban u v cc dung dch pha longXem ISO 6887 v ISO 8261.9.2. Cy v (k thut a)Dng mt pipette v trng (6.8), ht 1 ml huyn ph ban u, hoc ca cc mu th nghim nu sn phm ban u l dng lng, vo a petri khng (6.9) 10 ml n 15 ml mi trng thch SC (5.2.3), duy tr mc 440C n 470C trong b n nhit (6.10), vo cc a v dn u bng cch nh nhng xoay a. Khi mi trng ng c, b sung 10ml mi trng thch SC. cho mi trng ng li. t cc a trong bnh ln men ym kh hoc thit b cha thch hp (6,3) v trong iu kin ym kh 370C trong 20 h 2 h. Nu nui cy trong thi gian di C.perfringens pht trin qu mc s lm en a peptri.Tin hnh tng t vi cc mu pha long (xem 9.1).9.3. m v la chn khun lcSau thi gian nui cy, chn cc a c t hn 150 khun lc. T , la chn ra a thch hp i din cho nng pha long.m cc khun lc c trng ca C. perfringens trn mi a.Chn 5 khun lc c trng v xc nh chng bng 1 trong nhng k thut c m t trong 9.4.2 v 9.4.3.9.4. Cc phn ng ha sinh9.4.1. Tng quanChn mt trong hai k thut xc nh c m t trong 9.4.2 v 9.4.3.Phng th nghim sinh ha c th c s dng nu ph hp vi tiu chun ISO 7218.9.4.2. K thut s dng mi trng LS Lu : cc phn ng trong mi trng sulfite lactose khi nhit 46oC l rt ph hp cho Clostridium perfringens v Clostridium absonum. Do , khun lc en chn t mi trng thch khng cn thit phi l thun chng trc khi cy vo mi trng thioglycollate broth v sau vo mi trng sulfite lactose.9.4.2.1 Cy v Cy mi khun lc la chn (xem 9.3) vo mi trng thioglycollate lng (5.3). trong iu kin ym kh 370C trong 18 h n 24 h.Sau khi , nhanh chng ly 5 git thioglycollate vo mi trng LS bng pipet v trng. hiu kh 460C trong 18 h n 24 h trong b n nhit (6.10).9.4.2.2. Gii thchKim tra cc ng mi trng LS xem c sinh kh v c s xut hin ca 1 cht kt ta mu en (ta st sulfite) hay khng. Hn mt phn t ng Durham y kh v c kt ta mu en c coi l dng tnh.Trong trng hp nghi ng, khi cc ng Durham trong mi trng c mu en v lng kh t hn mt phn t, s dng pipet v trng, nh 5 git mi trng LS nui cy sinh trng trc vo ng mi trng LS khc (9.4.2.1). trong b n nhit (6.10) 460C trong 18 h n 24 h. Tip tc quan st ng ny.Vi khun m c khun lc c trng trong mi trng SC v n c xc nh dng tnh vi mi trng LS c coi l C.perfringens. Trong tt c cc trng hp khc c xem l m tnh.9.4.3. K thut s dng mi trng di ng nitrate v mi trng lactose-gelatin9.4.3.1. Tng quanK thut ny i hi phn lp c khun lc thun nht. Trng hp ngc li (ngha l trn b mt cc a mc qu dy c v khng c kh nng chn c khun lc c trng c phn lp tt) Cy 5 khun lc c trng vo mi trng thioglycollate lng c kh ht kh (5.3). trong iu kin ym kh 370C trong 18 h n 24 h. Dng que cy hnh kim, ly 1 t khun lc cy ln mi trng SC thch c bn (xem 5.2.1.2), tip theo 10 ml thch SC c bn ph ln trn. cho thch ng t nhin sau k kh 370C trong 18 h n 24 h. Chn t mi a t nht mt khun lc c trng. Nu cn thit, hy lp li nui cy v cy trn a thch SC c bn cho n khi thu c vi khun c mu en thun nhtXc nh vi khun ny nh m t trong 9.4.3.2, 9.4.3.3 v 9.4.3.4.9.4.3.2. Cy v quan st mi trng di ng ca nitratCy mi khun lc c la chn (xem 9.3) vo mi trng di ng nitrate kh ht kh (5.5). trong iu kin ym kh 370C trong 24 h. Kim tra cc ng mi trng nitrate s pht trin ca vi khun theo hng vt cy. S di ng l iu hin nhin t s pht trin lan ta ra vo mi trng i t ng m.Kim tra s hin din ca nitrite bng cch: dng pipette c chia (6.8) v ng ht cao su (6.11), ht 0,2 ml n 0,5 ml thuc th pht hin nitrite (5.6) vo mi ng mi trng nitrate.S hnh thnh ca mt mu chng t rng nitrate kh thnh nitrite. Nu khng c mu c hnh thnh trong vng 15 pht, thm mt lng nh bt km (5.7) v yn trong 10 pht. Nu mt mu c hnh thnh sau khi thm bt km th nitrate khng kh thnh nitrite. CNH BO - V l do sc khe, thc hin k thut kim tra ny di t ht.9.4.3.3. Cy v quan st mi trng lactose-gelatinCy mi khun lc la chn (xem 9.3) vo mi trng c lactose-gelatin kh ht kh (5.8). trong iu kin ym kh 370C trong 24 h.Kim tra cc ng mi trng lactose-gelatin, nu c s xut hin ca kh v c mu vng (do s hnh thnh acid) cho thy qu trnh ln men lactose xy ra. Lm lnh cc ng trong 1 gi 50C v cho gelatin ha lng. Nu mi trng vn ng c, li thm 24 h mt ln na cho gelatin ha lng hon ton.9.4.3.4. Gii thchVi khun pht trin thnh khun lc c mu en trong mi trng SC, khng di ng, kh nitrate thnh nitrite, to ra axit v kh t lactose, ha lng gelatin trong 48 h c cho l C. perfringens. Trong qu trnh nui cy m xy ra phn ng yu t to nitrite (tc l c mu hng) s c loi tr, v C. perfringens lun to ra mt phn ng d di v ngay lp tc.

10. Biu th kt qu10.1. Phng php tnh: Xem ISO 7218.10.2. chnh xc10.2.1. Th nghim lin phngS liu chnh xc cho cc phng php m t trong tiu chun ny c da trn kt qu ca mt th nghim trong th nghim lin phng (xem [2]). Chi tit v th nghim lin phng c tm tt trong Ph lc A. lp li v ti lp gi tr gii hn c xc nh bng cch s dng ba loi thc phm b nhim mc khc nhau v cc ti liu tham kho.Cc gi tr thu c t th nghim lin phng ny c th khng p dng i vi khong nng v cc cht lin kt khc nhng g ngi ta a ra.10.2.2. lp liS khc bit tuyt i gia hai yu t ring l (c chuyn thnh log10) kim tra kt qu (s C. perfringens/gram hoc C. perfringens/ ml), hoc t l cao hn / thp hn ca cc kt qu th nghim trn hai quy m bnh thng, thu c bng cch s dng cng mt phng php trn cng vt liu, do cng 1 ngi vn hnh cng mt thit b dng c tng t trong khong thi gian ngn nht, s khng ln hn 5% cc trng hp vt qu gii hn lp li (r).Nh mt du hiu chung ca lp li (r), cc gi tr sau y c th c s dng khi kim tra cc mu thc phm ni chung. Nhng gi tr tng qut khng c ngha l i din cho tt c cc ma trn c xem xt th nghim lin phng:sr = 0,21 cho LS hoc 0,25 cho MN / LG (th hin nh mt s khc bit gia cc kt qu th nghim c chuyn thnh log10); hocsr= 1,67 cho LS hoc 1,8 cho MN / LG (th hin di dng mt t l cao hn n thp hn ca cc kt qu th nghim hai).i vi cc ti liu tham kho (xem Bng A.4), cc gi tr sau y c th c s dng:sr= 0,13 cho LS hoc 0,12 cho MN / LG (th hin nh mt s khc bit gia cc kt qu th nghim c chuyn qua log10); hocsr= 1,3 cho LS hoc 1,8 cho MN / LG (th hin di dng mt t l cao hn n thp hn ca hai kt qu th nghim)V d: ln u tin quan st c 10000 hoc 1,0 x 104 loi vi khun c cho l C. perfringens trn 1 gam mu thc phm. Lp li quan st, t l gi tr ln hn v b hn khng c vt qu 1,9. V vy, kt qu th hai nn c gia 5263 (= 10 000 / 1,9) v 19 000 (10 000 1,9) vi khun c cho l C. perfringens/gam (5263,19000).10.2.3. ti lpS khc bit tuyt i gia hai yu t ring l (c chuyn thnh log10) kim tra kt qu (s C. perfringens/gram hoc C. perfringens/ ml), hoc t l cao hn / thp hn ca cc kt qu th nghim trn hai thang danh nh, nhn c bi cng mt phng php, trn cc mu th ging ht nhau trong cc phng th nghim khc nhau, vi nhng ngi thao tc khc nhau, s dng cc thit b khc nhau trong khong thi gian ngn nht, s khng ln hn 5% cc trng hp vt qu gii hn ti lp (R).Nh mt du hiu gii hn ti lp (R), cc gi tr ca Bng 1 c th c s dng cho cc loi thc phm khc nhau v cc vt liu mu c th nghim. Nhng gi tr ny l cc gi tr thu c trong th nghim lin phng cho cc mc khc nhau (1)Bng 1. V d cc gi tr ca RLoi muLSMN v LG

R(log)aRbR(log)aRb

Ph mai0,261,80,312,1

Tht0,553,50,523,3

Thc n gia sc dng kh0,654,50,725,3

Nguyn liu mu0,271,90,291,9

a: R(log) l gii hn ti lp th hin s khc bit gia cc kt qu th nghim b: R l gii hn ti lp th hin t l gia cc kt qu th nghim.

Ph lc A (tham kho)Kt qu th nghim lin phng.Mt th nghim hp tc quc t (xem [2]) bao gm 17 phng th nghim 15 quc gia c thc hin trn mu pho mt, tht, thc n gia sc kh v mt ti liu tham kho. Cc mu thc phm / mu thc n tng c th nghim ba mc nhim khc nhau vi Clostridium perfringens.Ph hp vi tiu chun ISO 16140, cc thng s sau c xc nh trong cc th nghim lin phng. Th nghim ny c t chc bi Vin Y t cng ng (RIVM) H Lan vo thng 1 nm 2000 v a cc d liu chnh xc th hin trong Bng A.1 n A.4.

Bng A.1 - Kt qu phn tch d liu thu c vi mu phomat.MuPhomat (mc thp)Phomat(mc trung bnh)Phomat (mc cao)

S phng th nghim vi kt qu hp l131313

S mu222

S phng th nghim c gi li sau khi loi tr gi tr ngoi tr131313

S gi tr loi tr000

S mu c chp nhn262626

Gi tr trung bnh (log10 cfu/g)2,5/2,5a3,5/3,5a

4,5/4,5a

lch chun lp li sr (log10 cfu/g) lch chun lp li tng i (%)0,11/0,11a4,37/4,59a0,06/0,07a1,63/1,97a

0,08/0,10a1,85/2,31a

Gii hn lp li, r Theo chnh lch trn thang log10 (log10 cfu/g) Theo t s trn thang danh nh (cfu/g)0,30/0,32a

2,0/2,1a

0,16/0,19a

1,5/1,6a

0,23/0,29a

1,7/1,9a

lch chun ti lp sR (log10 cfu/g) lch chun ti lp tng i (%)0,13/0,13a5,21/5,11a0,08/0,15a2,32/4,38a0,11/0,14a2,50/3,11a

Gii hn ti lp, R Theo chnh lch trn thang log10 (log10 cfu/g) Theo t s trn thang danh nh (cfu/g)0,36/0,35a

2,3/2,2a0,23/0,43a

1,7/2,7a

0,31/0,39a

2,1/2,4a

a Kt qu u tin c s dng mi trng lactose-sulfite/ mi trng di ng nitrate v ln th hai vi mi trng lactose-gelatin

Bng A.2 - Kt qu phn tch d liu thu c vi mu tht bm.MuTht bm (mc thp)Tht bm(mc trung bnh)Tht bm (mc cao)


S mu222


S gi tr loi tr000


Gi tr trung bnh (log10 cfu/g)2,7/2,7a3,6/3,6a4,5/4,5a

lch chun lp li sr (log10 cfu/g) lch chun lp li tng i (%)0,06/0,11a2,32/4,22a0,06/0,10a1,67/2,70a0,11/0,09a2,33/2,01a


1,5/2,1a0,17/0,27a

1,5/1,9a

0,29/0,25a

2,0/1,8a



2,4/3,1a

0,51/0,50a

3,2/3,2a

0,49/0,60a

3,1/4,0a


Bng A.3 - Kt qu phn tch d liu thu c vi thc n gia sc kh.MuThc n gia sc(mc thp)Thc n gia sc (mc trung bnh)Thc n gia sc(mc cao)


S mu222


S gi tr loi tr000


Gi tr trung bnh (log10 cfu/g)2,6/2,6a3,8/3,9a4,8/4,9a

lch chun lp li sr (log10 cfu/g) lch chun lp li tng i (%)0,07/0,10a2,85/3,79a0,08/0,08a2,09/1,93a0,06/0,04a1,22/0,75a


1,6/1,9a

0,22/0,21a

1,7/1,6a

0,16/0,10a

1,5/1,3a



7,6/7,6a0,69/0,67a

4,9/4,7a0,47/0,47a

3,0/3,0a


Bng A.4 - Kt qu phn tch d liu thu c vi cc vt liu chun.MuVt liu chun


S mu2


S gi tr loi tr0

S mu c chp nhn26

Gi tr trung bnh (log10 cfu/g)3,7/3,7a

lch chun lp li sr (log10 cfu/g) lch chun lp li tng i (%)0,05/0,05a1,24/1,21a


1,3/1,3a

lch chun ti lp sR (log10 cfu/g) lch chun ti lp tng i (%)0,09/0,09a2,51/2,39a


1,8/1,8a


c. perfringens

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