Stephenson P, Satchell F B, Allen G, Andrews W H
Food and Drug Administration, Division of Microbiology, Washington, DC 20204.
J Assoc Off Anal Chem. 1991 Sep-Oct;74(5):821-6.
A preenrichment procedure and a direct selective enrichment procedure were compared for recovery of Salmonella artificially inoculated into liquid whole egg, egg yolk, and egg albumen. For liquid whole egg and egg yolk, the 2 procedures were comparable. With egg albumen, however, preenrichment in lactose broth gave significantly higher recoveries than did direct selective enrichment in either selenite cystine or tetrathlonate broths. The lactose preenrichment procedure was used to determine the survival of S. enteritidis in egg yolk and egg albumen over a period of 7 days. As shown by most probably number determinations, counts of S. enteritidis inoculated into egg albumen decreased by 3 log units, whereas those in egg yolk did not change significantly. It is recommended, therefore, that only the egg yolk be examined for this pathogen. In a comparison of 5 different preenrichment media (lactose broth, brain heart infusion broth, trypticase soy broth, buffered peptone water, and nutrient broth), lactose broth was somewhat less productive than the other 4 media for the recovery of Salmonella from egg yolks. Trypticase soy broth gave the highest recovery.
比较了预富集程序和直接选择性富集程序对人工接种到全蛋液、蛋黄和蛋清中的沙门氏菌的回收率。对于全蛋液和蛋黄，这两种程序的效果相当。然而，对于蛋清，在乳糖肉汤中进行预富集比在亚硒酸盐胱氨酸肉汤或四硫磺酸盐肉汤中进行直接选择性富集的回收率显著更高。采用乳糖预富集程序测定肠炎沙门氏菌在蛋黄和蛋清中7天内的存活情况。如最大可能数测定所示，接种到蛋清中的肠炎沙门氏菌数量减少了3个对数单位，而蛋黄中的数量没有显著变化。因此，建议仅对蛋黄进行该病原体检测。在比较5种不同的预富集培养基（乳糖肉汤、脑心浸液肉汤、胰蛋白胨大豆肉汤、缓冲蛋白胨水和营养肉汤）时，乳糖肉汤从蛋黄中回收沙门氏菌的效率略低于其他4种培养基。胰蛋白胨大豆肉汤的回收率最高。
