SN T 1897-2007 食品中菌落总数的测定Petrifilm 测试片法.pdf

1、、. . . , 中华人民共和国出入境检验检疫行业标准SN/T 1897-2007 食品中菌落总数的测定Petrifilm 测试片法Aerobic pate count in foods一Petrifilrn aerobic coont plate method 2007-05皿23发布2007-12二01实施 - r -中华人民共和国发布国家质量监督检验检疫总局标准拨拨网阳飞饥bzsoso，com各类标准行业资料免费下载-. . . 1 范围食晶中菌落总数的测定Petrifilm测试片法本标准规定了食品中菌落总数的测定CPetrifilm测试片法)。SN/T 1897-2007 本标准适用于

2、食品及原料中菌落总数的测定，也可以用于与食品接触的容器、操作台和其他设备表面的卫生检测。2 规范性引用文件下列文件中的条款通过本标准阳引用而成为本标准的条款。用是注日期的引用文件，其随后所穷的修改单(不包括勘误的内容)或彦37腹弱不适用尹本标准，然而v鼓励根据本标准达成协议的各方研究J 是否可使用这些文件的最新版本。凡是不寻A期的引用文ff:其最新版本适用于本标准。SN 0168 出口食品平板菌落计数3 术语和定义下列术语和定义适用于本标准。3. 1 菌落总数aerobic plate count ，.，.-一-飞、样品经过处理，在一定条件下培抖，所得1ILi(g)检样苟且单位面积样品中所含菌

3、落的总数。3.2 菌落形成单位colony-fol喃inguDi cfu 一个细菌在平板计数琼脂&培养基上生长形烧肉眼4 原理4. 1 Petrifilm 细菌总数测谎片Aefob-idcountp!ates是J一种预先制备好的培养基系统，含有标准的培养基，冷水可溶性的凝胶剂牙切氯化三苯1四氮瞠(甘C)指示剂，菌落在测试片上呈红色或粉红色，这样可增强菌落计数效果。4.2 3M快速涂抹捧(QuckSw说是一种预先制备娟的环搓涂抹系统，可以用于食品、饮料工业中的表面采样程序。3M快速涂抹棒可以和所有3MPetrifilm 测试片一起使用。它包括o.127 m (5 in) 长的人造纤维涂抹头和1.

4、4mL的letheen肉汤letheen肉汤可以中和残留于被测物表面的消毒剂，o. 127 m (5 in)长的人造纤维涂抹头可涂抹弯曲管道。QuickSwab涂抹棒的纤维涂抹头和letheen肉汤是分开的，适合于干、湿两种取样方式。4.3 3M e Swab涂抹棒是一种预先制备好的环境涂抹系统，可以用于食品、饮料工业中的表面采样程序。3Me Swab涂抹棒可以和大部分3MPetrifilm 测试片一起使用。它包括人造纤维涂抹头和10mL缓冲蛋白陈水溶液。3Me. Swab涂抹棒的一侧标有刻度，根据刻度可以在测试片上滴加确定体积的溶液。5 设备和材料5. 1 温箱:36 oc士lOC，30oC

5、土lOC。. . 标准拨拨网阳飞饥各类标准行业资料免费下载 . . SN/T 1897-2007 中央处，将上层膜盖下，允许上层膜直接落下，但不要滚动上层膜，将压板(凹面底朝下)放置在上层膜中央处，轻轻地压下，使样液均匀覆盖于圆形的培养面积上，拿起压板，静置至少1mn以使培养基凝固。每个稀释度接种两张测试片，每张1mLo 8.4 表面取样的样品表面取样的样品如拭子)参见附录A。8.5 空气取样的样品空气取样的样品参见附录B。8.6 培养将测试片的透明面朝上水平置于培养箱内，可堆叠至20片，360C土lOC条件下培养48h士2h(水产品300C土lOC培养72h土3h) ;如有产品标准等特殊要求

6、，则按相应的标准或要求进行。8. 7 菌落计数和记录8. 7. 1 到培养时间后应立即计数，如果不能立即进行计数，可以将测试片放在一150C条件以下，不超过7 do 8.7.2 计数红色菌落，菌落计数和记录见SN016811 8.8 菌落计数说明8. 8. 1 不论菌落大小都应计数。8.8.2 当细菌浓度很高时，整个测试片会变成红色或粉红色，将结果记录为多不可计(too numerous to count , TNTC)。8.8.3 有时细菌浓度很高时测试片中央可能没有可见菌落，但圆形培养面积的边缘有许多小的菌落.其结果也记录为多不可计(TNTC);可对样品进行进一步的稀释，以获得准确的计数。

7、8.8.4 一些微生物会液化凝胶营造成局部扩散或菌落模糊的现象。如果液化现象干扰计数，可以计数未液化的面积来估算菌落浓度。8.9 计数和记录数据计数和记录数据见SN01680 9 结果的表述菌落计算的规则同SN0168。固体检样以CFU/g为单位报告，液体检样以CFU/mL为单位报告，表面涂抹则以CFU/cm2报告。，、. 标准拨拨网阳飞饥各类标准行业资料免费下载 . . 附录B(资料性附录)空气取样方法(直接沉降法)B. 1 用1mL无菌稀释液水化3MPetrifilm菌落总数测试片。B.2 静置测试片至少1h，使胶体固化(水化好的测试片可以冷藏7d)。B.3 在3M固定夹的两端粘上双面胶带

8、。B.4 提起上层膜并贴于胶带上固定，将测试片于空气中暴露15min。B.5 合上上层膜后置于培养箱内按规定条件培养。. 标准拨拨网阳飞饥各类标准行业资料免费下载SN/T 1897-2007 5 、. . SN/T 1897-2007 Foreword 丁hisstandard mainly refers to AOAC 990. 123M Petrifi 1m 1MAerobic Count Plate Method Annex A and a门nexB are informat ive. This standard was proposed bCertification and Accre

9、ditation Adminstrator of the PeopleJ s Republic of China ( CNCA) , and is under the jurisdiction of CNCA. The standard was drafted bLiaoning Entry-exit Export Inspection and Ouarantine Bureau of P. R. China , Heilongjiang Entry.exit Export Inspection and Quarantine Bureau of P. R. China, Shenzheng E

10、ntry-exit Export Inspection and Quarantine Bureau of P. R. China , Dalian New Era technology devel opment Itd. ,3M Ch ina Ltd . The main drafers of this standard are Lu Xing-an , Cao Jijuan, Li Sulong , Wu Gang , Xie Zhaocong , Qin Cheng , Zheng Qiuyue, Qi Zhenyu , Wang Yuping , Qu Chi , Liu Ran , Y

11、u Chunmel , Zhou Zhenya and Lu Subiao. This standard is a professional standard of entry-exit inspection and quarantine promurgated for the first time. ，、. 1) Petrifilm is the trademark of 3M company. 标准拨拨网阳飞饥各类标准行业资料免费下载7 . . . SN/T 1897-2007 4 Principle 4.1 3M Petrifilm Aerobic count plates: Petri

12、film plate are a ready-to-use product containng the standard medium, a cold-water-soluble gelling agent and TTC indicator that can enhance the effect of colony enumeration. 4.2 3M Quick Swab:lt is a ready-to-use environmental swab system which is applied to the sam pling program on the surface in fo

13、od and beverage industry. 3M Quick Swab can be used with al the 3M Petrifilm Plates. It conssts of O. 127 m (5in) long Oacron tipped swab that uses 1.4 mL Jetheen broth to faci I itate the recover-y Qf闵创仓ritketheerrbrottrJeanneutralize the residual saniti zers on the surface,O. 127 m (5 iO) a.rtific

14、l fibre.an swab the curvibg pipe. Quick Swab can be used to the dry and wet sampling moqe 4. 3 3M e Swab: It is a ready-to-use environr11etal swab stem which is applied to the sampling program on the surface in food and beverqg industry. Te 3M e Swab is designed to be used with most 3MTh1 Petrifil俨p

15、late.It cons命a10 mm)fg即onswab head and contains 10 niL buff-. _ _ t _ 1 . ._ ,?_ - . . t I ered peptone water or phosphate .bUffe-rd sanne_:tM-e-Swa-ftas volume scale on sides , and it can be used to附栩栩mplewih roper voJume Of).to阳Pet州TMpl剖es. 5 Equipment and materials 5. 1 Incubator:36t士10C5. 2 Refr

16、igerator: 20C 5 oC . 5. 3 pH meter or precise pH p争pet.5.4 magnifier and/ or colonc句unteror 3MPetriJilmTMlplate re.叫er.6 Media and agent 6. 1 1 mol/ L NaOH: Weigh 40 9 NaOH and then dissolve jt into 1 000 ml distilled water. 6.2 1 mol/L HCI: Pipe 90 mL HCI , and then dilute it into 1 000 mL distlled

17、 water. 6. 3 3M Petrifilm Aerobic Count Plate and spreader. 6. 4 3M Quick Swab and 3M e Swab. . . -. . 标准拨拨网阳飞饥各类标准行业资料免费下载9 、. . SN/T 1897-2007 suspension over prescribed growth area with downward pressure in center of plastic spreader device (recessed side down). Leave plate undisturbed at least 1

18、 min to permit gel to solidify. Two plates were inoculated for each dilution, and 1 mL for each plate. 8. 4 Surface sampling See Annex A. 8. 5 Air sampling See Annex B. 8. 6 Incubation In incubator, place plates in horizontal position, clear side up, in stacks not exceeding 20 units. The incubation

19、condition is 48 h士2h for 360C士1oC (For seafood , the conditon is 72 h士3h for 300C士1 QC ); In accordance to the corresponding standard or requirement if there is the specific requirement or standard for the products. 8.1 Enumeration and record 8.7. 1 Count plates promptly after incubation period. Aft

20、er incubation is complete, plates may be stored frozen ( -15QC ) up to 7 days. Avoid this as a routine practice. 8.7. 2 Count red colony , and the calculation and record is in accordance with SN 0168. 8. 8 Interpretation of results 8. 8. 1 Count the red colonies regardless of its size or intensit. 8

21、. 8. 2 When there is high concentration of bacteria, the whole plate will turn red or pnk. And the result will be counted as TNTC (too numerous to count). 8. 8. 3 Occasionally , on overcrowded plates , the center malack visible co(onies but mansmall colonies will be seen on飞heedges. When th is occur

22、s, record results as TN丁C;further dlution of the sample is required. 8.8.4 Some organisms ca门liquefythe gel , allowing them to spread out and obscure the presence of other colonies. If a liquefier interferes with counting, an estimated count should be made by counting the unaffected areas. a 11 标准拨拨

23、网阳飞饥各类标准行业资料免费下载. . . SN/T 1897-2007 Annex A ( Informative) Su rface sampl ng methods The microbial detection on the surface of the food contact container, operation table and other equipment can be applied to evaluate the contamination level in product process or sanitization effect of product hygi

24、ene2) Surface sampling methods include the surface swab method and direct plate contact method. A. 1 Surface swab Method The slze of the sampling area .dep_eods For instance, considering the low number ot ltn .Jnt.r.nB1 standard, and/ or monitoring place. rgger sampl i ng area can be appl ied to the

25、 product lne. A. 1. 1 3M Quick Swab A. 1. 1. 1 Bend the red snap vlve and release tij_e ltne- r.t 忧6协tothe tube. 00 not bend the red snap first when the swab is ued for drv mode _5a A. 1. 1. 2丁akeout the swab from千orsampli用A. 1. 1. 3 r sa付1epoint. A. 1. 1.4 igorously for 10 s8conds. A. 1. 1. 5 Relea

26、se the sampff) onto the M Petfi 1m Terobie;.tount Plate. A. 1. 2 3M e Swab . 1. 2. 1 Label the container with sample information. A. 1. 2. 2 Unscrew the cap and remove the swab. A. 1. 2. 3 Swab the defined test area. 2 ) Stability is the key poiot for getting the useful information in the process of

27、 environmental monitoring , so the same procedure should be applied to the sampling process. In ideal circumstance , the same types of sampling equipment , template area , technician and sampling technologies should be applied. . . 、标准拨拨网阳飞饥各类标准行业资料免费下载13 -2 . SN/T 1897-2007 Annex B ( Informative) A

28、ir sampJing method (Direct air sediment method) B. 1 Hydrate Petrifilm Aerobic Count plates with 1 mL of appropriate sterile diluent. B. 2 Allow the hydrated plates to remain closed for a minimum of 1 hour before use to solid ify the gel (hdrated Petriflm Aerobic Count plate can be refrigerated for

29、up to 7 days). B. 3 Attach the double-side tape on the two side of the 3M clip. B.4 Lift the top fjlm and adher.e to the tape, and expose it in air for 15 min. B. 5 Rejoin the top film and then put it in the incubator according to the specified condition. 睛.t . 标准拨拨网阳飞饥各类标准行业资料免费下载标准资料收藏家易启标准网免费提供十万标准书籍资料下载会打字、5分钟快速自助建网站易启建站网免费提供建站平台，商业网站1年仅60元标准资料收藏家易启标准网免费提供十万标准书籍资料下载会打字、分钟快速自助建网站易启建站网免费提供建站平台，商业网站年仅元