Abstract: In order to ensure the quality of raw milk and enrich quality control strains for the acceptance evaluation of culture media for the detection of coliform bacteria in raw milk, three brands of violet red bile agar (VRBA), violet red bile agar with 4-methylumbelliferyl-β-D-glucuronidehydrate (VRBA-MUG), lauryl tryptose broth (LST) and brilliant green lactose bile broth (BGLB) were selected and evaluated for their physical indicators such as appearance, pH and moisture content as well as microbial indicators such as growth rate and selectivity using the methods specified in China’s national standard for quality requirements for culture media and reagents in food microbiological examination (GB 4789.28-2013). Besides, using Citrobacter freundii ATCC 43864 as a reference strain, seven strains of C. freundii were selected for acceptance evaluation of the four media. The results showed that the color of all three brands of dry powdered media was normal. Their moisture content was 5%–6%, and their pH was in line with the national standard. The growth rate of the seven tested strains of C. freundii was greater than 0.7 on the three brands of VRBA and VRBA-MUG, while only CMCC 48098 and CICC 22910 achieved turbidity of 2 on the three brands of LST and BGLB, and produced gas in the catheter; the same results were obtained with ATCC 43864. In summary, the three brands of VRBA, VRBA-MUG, LST and BGLB all comply with GB 4789.28-2013, and CMCC 48098 and CICC 22910 can be recommended as supplements to quality control strains for the acceptance evaluation of the four media.

Key words: raw milk; media for food testing; coliforms; quality control strains; quality control

摘要： 为保证原料乳质量，丰富检测原料乳中大肠菌群涉及到的培养基的验收质控菌株，采用GB 4789.28—2013《食品安全国家标准 食品微生物学检验 培养基和试剂的质量要求》中规定的验收方法，分别选取3 个品牌的结晶紫中性红胆盐琼脂（violet red bile agar，VRBA）、结晶紫中性红胆盐-4-甲基伞形酮-β-D-葡萄糖苷琼脂（violet red bile agar with MUG，VRBA-MUG）、月桂基硫酸盐胰蛋白胨肉汤（lauryl tryptose broth，LST）和煌绿乳糖胆盐肉汤（brilliant green lactose bile broth，BGLB），对其进行外观、pH值、水分含量等物理指标以及生长率、选择性等微生物指标实验评价。同时以弗式柠檬酸杆菌ATCC 43864为参照，选取7 株弗式柠檬酸杆菌对3 个品牌的VRBA、VRBA-MUG、LST和BGLB进行验收实验评价。结果表明：3 个品牌的不同培养基干粉颜色均正常，水分含量均控制在5%～6%，pH值均符合国家标准；7 株弗氏柠檬酸杆菌在3 个品牌VRBA、VRBA-MUG上的生长率均大于0.7；仅CMCC 48098和CICC 22910在3 个品牌的LST、BGLB中浊度达到2，且导管内产生气体，与ATCC 43864结果相同。综上，3 个品牌的VRBA、VRBA-MUG、LST和BGLB全部符合GB 4789.28—2013，推荐CMCC 48098和CICC 22910用作验收4 个培养基质控菌株的补充菌株。

关键词: 原料乳；食品检验用培养基；大肠菌群；质控菌株；质量控制