食品微生物檢測培養(yǎng)基分類，成分和采購質(zhì)量指南
發(fā)布時間：
2022-12-27
作者：
近年來，一向以食品安全監(jiān)管嚴(yán)格著稱的美國和歐洲發(fā)達(dá)國家屢遭食源性致病菌導(dǎo)致的疾病危害，其中美國一年內(nèi)連續(xù)發(fā)生了沙門氏菌、大腸桿菌、單增李斯特菌污染造成的食品安全事件，德國腸出血性大腸桿菌傳染病的爆發(fā)也波及了很多國家。微生物性食源性疾病可以說是全球食品安全問題之首。
隨著我國對食品安全的重視及人民健康意識的提高，食品檢驗越來越嚴(yán)格也越來越頻繁，在檢測項目中，微生物的檢測尤為重要，在這項檢測中微生物檢測培養(yǎng)基的選擇是關(guān)鍵，培養(yǎng)基的質(zhì)量對檢測結(jié)果的影響非常重要。
目前，微生物檢測中的各種培養(yǎng)基及其對應(yīng)用途如下：
革蘭氏染色液，微生物染色；營養(yǎng)瓊脂，細(xì)菌培養(yǎng)和細(xì)菌總數(shù)測定；孟加拉紅培養(yǎng)基，霉菌酵母菌計數(shù)；乳糖膽鹽發(fā)酵管，大腸菌群，糞大腸菌群及大腸桿菌的測定；乳糖發(fā)酵管，供大腸菌群證實實驗用；三糖鐵瓊脂，腸桿菌科細(xì)菌的生化反應(yīng)帥選；伊紅美藍(lán)瓊脂，分離腸道致病菌；緩沖蛋白胨水，沙門氏菌檢驗中的前增菌；GN增菌液，志賀氏菌的前增菌；亞硒酸鹽胱氨酸增菌液，沙門氏菌選擇性增菌培養(yǎng)；ss瓊脂，沙門氏菌和志賀氏菌的分離；V-P半固體瓊脂，細(xì)菌檢驗的VP試驗；7.5錄酸鈉肉湯，金黃色葡萄球菌的增菌培養(yǎng)；baird-Parker培養(yǎng)基，金黃色葡萄球菌的檢驗；酸性肉湯，酸性罐頭食品商業(yè)無菌檢驗；尿素瓊脂基礎(chǔ)，細(xì)菌檢驗中的賴氨酸脫霉試驗；硝酸鹽氰化鉀培養(yǎng)基，細(xì)菌檢驗中的硝酸鹽還原試驗和氰化鉀試驗；生理鹽水，檢驗的溶解與稀釋。
其中，沙門氏菌-志賀氏菌瓊脂培養(yǎng)基（簡稱SS瓊脂）是分離腸道致病菌最常用的強選擇性培養(yǎng)基。根據(jù)相關(guān)標(biāo)準(zhǔn)，SS瓊脂完全培養(yǎng)基配方如下：
（g/L）牛肉膏 5，三號膽鹽 3.5，瓊脂 17，乳糖 10，檸檬酸鈉 8.5，硫代硫酸鈉 8.5，10%檸檬酸鐵溶液 10ml，1%中性紅溶液 2.5ML，0.1%黃綠溶液 0.33ml。
國際標(biāo)準(zhǔn)化組織（ISO）在本世紀(jì)初制定了實驗室培養(yǎng)基制備的質(zhì)量保證通用指南。我國在2002年8月頒布了《實驗室認(rèn)可準(zhǔn)則在微生物檢測實驗室的應(yīng)用說明》，明確要求實驗室應(yīng)建立和保持有效的適合試驗范圍的培養(yǎng)基質(zhì)量控制程序，對自備和商品培養(yǎng)基都需要評估，不得使用不符合要求的培養(yǎng)基。
由于SS瓊脂的內(nèi)在質(zhì)量優(yōu)劣直接影響到腸道致病菌的檢出率，因此對該類培養(yǎng)基質(zhì)量要求較高，要求沙門氏菌、志賀氏菌等致病菌在SS 瓊脂平板上均生長良好，而大腸桿菌及其它非致病菌的生長則受到抑制。在《中國藥典》上SS瓊脂屬于微生物限度檢查法中規(guī)定的培養(yǎng)基。
SS瓊脂的重要作用體現(xiàn)在食品等行業(yè)中，主要用于沙門氏菌、志賀氏菌的選擇性分離培養(yǎng)。沙門氏菌、志賀氏菌是引起人類食源性疾病的重要病原菌。沙門氏菌主要寄生在人體、哺乳動物和家禽的腸道內(nèi)，可隨糞便污染水源、食品與藥品等，引起傷寒癥、急性胃腸炎和敗血癥等。據(jù)統(tǒng)計在世界各國的細(xì)菌性食物中毒中，沙門氏菌引起的食物中毒常列榜首。中國內(nèi)陸地區(qū)也以沙門氏菌為首位。而志賀氏菌病是人和靈長類的腸道致病菌，常經(jīng)食物或水傳播，引起細(xì)菌性痢疾，嚴(yán)重者引起發(fā)熱，神志障礙，甚至中毒性休克等。
Food microbiology testing guidelines for media classification, composition and procurement quality
In recent years, the United States and the developed countries in Europe, which are famous for their strict food safety supervision, have suffered from food-borne pathogenic bacteria. In the United States, food safety incidents caused by contamination of Salmonella, Escherichia coli and Listeria monocytogenes have occurred successively in one year, and the outbreak of enterohemorrhagic E.coli infectious disease in Germany. Also spread to many countries. Microbial foodborne diseases can be said to be the leading global food safety problem.
With the emphasis on food safety and the improvement of people's health awareness, food inspection is becoming more and more strict and frequent. In the detection project, the detection of microorganisms is particularly important. In this detection, the selection of microbial detection medium is the key, and the quality of culture medium is very important to the detection results.
At present, various media and their corresponding uses in microbial detection are as follows:
Gram's staining solution, microbial staining; nutrient agar, bacterial culture and total bacterial count; Bangladesh red medium, mold yeast count; lactose and bile salt fermentation tube, coliform group, fecal coliform group and coliform bacteria determination; lactose fermentation tube, for the confirmation of coliform group experiment; trisaccharide iron agar, Enterobacter Biochemical reaction of family Bacteria; Eosin methylene blue agar, isolation of enteropathogenic bacteria; Buffer peptone water, Salmonella test in the pre-increase bacteria; GN enrichment liquid, Shigella pre-increase bacteria; Selenite cystine enrichment liquid, Salmonella selective enrichment culture; SS agar, Salmonella and Shigella isolation; Semi-solid agar, VP test for bacterial test; 7.5 Sodium Record Broth, Enhanced Culture of Staphylococcus aureus; Baird-Parker Medium, Staphylococcus aureus test; Acidic broth, commercial sterility test for acidic canned food; Urea agar base, lysine demildew test for bacterial test; Nitrate potassium cyanide culture Nitrate reduction test and potassium cyanide test in nutrient, bacterial test; normal saline, test dissolution and dilution.
Salmonella - Shigella agar medium (SS agar) is the most commonly used strong selective medium for isolation of enteropathogenic bacteria. According to the relevant standards, the SS agar medium formula is as follows:
(g/L) Beef paste 5, bile salt 3.5, agar 17, lactose 10, sodium citrate 8.5, sodium thiosulfate 8.5, 10% ferric citrate solution 10 ml, 1% neutral red solution 2.5 ML, 0.1% yellow-green solution 0.33 ml.
At the beginning of this century, the International Organization for Standardization (ISO) formulated a general quality assurance guide for laboratory culture media preparation. In August 2002, China promulgated the "Laboratory Accreditation Criteria for the Application of Microbial Testing Laboratories", which explicitly requires that laboratories should establish and maintain effective quality control procedures for the culture media suitable for the test range. Both commercial and self-contained media should be evaluated and should not be used with non-conforming media.
As the internal quality of SS agar directly affects the detection rate of intestinal pathogenic bacteria, so the quality of this kind of culture medium is required to be high, requiring that pathogenic bacteria such as Salmonella, Shigella grow well on the SS agar plate, while the growth of E. coli and other non-pathogenic bacteria is inhibited. In the Chinese Pharmacopoeia, SS agar belongs to the culture medium specified in microbial limit test.
SS agar plays an important role in food and other industries, mainly used for selective isolation and culture of Salmonella, Shigella. Salmonella and Shigella are important pathogens causing food borne diseases in humans. Salmonella mainly parasitic in the human body, mammals and poultry intestinal tract, can contaminate water sources, food and drugs with feces, causing typhoid fever, acute gastroenteritis and sepsis. According to statistics in the world of bacterial food poisoning, Salmonella caused by food poisoning often ranks first. Salmonella is also the first place in inland China. Shigellosis is an intestinal pathogen of human and primates, often transmitted by food or water, causing bacterial dysentery, severe fever, mental disorders, and even toxic shock.