D'Aoust J-Y, Sewell A, Jean A
Food Directorate, Health Protection Branch, Health and Welfare Canada, Sir Frederick G. Banting Research Centre, Tunney's Pasture, Ottawa, Ontario, Canada K1A 0L2.
J Food Prot. 1990 Jul;53(7):562-565. doi: 10.4315/0362-028X-53.7.562.
Short (6 h) enrichment under five different selective conditions adversely affected the isolation of Salmonella from pre-enriched samples of naturally contaminated foods. Of the 109 high moisture and 18 low moisture foods found to contain salmonellae following conventional (24 h) enrichment, combined results of the abbreviated enrichment procedures identified only 99 (90.8%) and 13 (72.2%) contaminated samples, respectively. The productivities of tetrathionate brilliant green (TBG) and Muller-Kauffman tetrathionate (MKTBG) broths consistently exceeded that obtained with the modified Rappaport (RV), tetrathionate brilliant green (TBG), and selenite cystine (SC) media after 6 and 24 h of incubation. Semi-quantitative analyses of growth under all enrichment conditions indicated that short (6 h) enrichment negatively affected method sensitivity through reduced numbers of Salmonella colonies and heavy growth of nonsalmonellae on bismuth sulfite (BSA) and brilliant green sulfa (BGS) plating media. These findings raise concerns on the dependability of commercial diagnostic schemes that incorporate abbreviated (6 h) enrichment in TBG and/or SC in their analytical protocol.
在五种不同选择条件下进行短时间（6小时）增菌，对从天然污染食品的预增菌样品中分离沙门氏菌产生了不利影响。在经过常规（24小时）增菌后发现含有沙门氏菌的109种高水分食品和18种低水分食品中，简略增菌程序的综合结果分别仅鉴定出99个（90.8%）和13个（72.2%）受污染样品。在培养6小时和24小时后，四硫磺酸钠煌绿（TBG）肉汤和穆勒 - 考夫曼四硫磺酸钠（MKTBG）肉汤的产率始终超过改良Rappaport（RV）肉汤、四硫磺酸钠煌绿（TBG）肉汤和亚硒酸盐胱氨酸（SC）培养基。在所有增菌条件下对生长进行的半定量分析表明，短时间（6小时）增菌通过减少沙门氏菌菌落数量以及在亚硫酸铋（BSA）和煌绿磺胺（BGS）平板培养基上非沙门氏菌的大量生长，对方法灵敏度产生了负面影响。这些发现引发了对商业诊断方案可靠性的担忧，这些方案在其分析流程中采用了在TBG和/或SC中进行简略（6小时）增菌的方法。
