Weagant Stephen D, Bryant James L, Bark Don H
U.S. Food and Drug Administration, Seattle District Laboratory, Bothell, Washington 98041.
J Food Prot. 1994 Jul;57(7):629-631. doi: 10.4315/0362-028X-57.7.629.
Three Escherichia coli Ol57:H7 (EHEC) strains were inoculated separately into portions of commercially prepared mayonnaise held at 25 or 7°C, then examined periodically for survival of detectable EHEC. Four mayonnaise-based sauces including: a) mayonnaise-mustard sauce, b) blue cheese dressing, c) thousand island dressing and d) seafood sauce, were each inoculated with one EHEC strain. Samples of these sauces were held at 5°C, and assayed periodically for survival of detectable EHEC. Both direct plate count and selective enrichment recovery were employed as assay procedures. Escherichia coli O157:H7 strains, when inoculated and mixed into mayonnaise and stored at 25°C, became undetectable after 72 h storage when assayed by direct plating or by selective enrichment. The same strains inoculated into mayonnaise and stored at 7°C were detectable up to 35 days when assayed by direct plating or by selective enrichment. Escherichia coli O157:H7 inoculated into mayonnaise-based sauces and held at 5°C were detectable past 35 days in three of the four sauces. Loss of EHEC culturability occurred within 3 days in mayonnaise-mustard sauce.
将三株大肠杆菌O157:H7（肠出血性大肠杆菌）分别接种到保存在25℃或7℃的市售蛋黄酱中，然后定期检测可检测到的肠出血性大肠杆菌的存活情况。四种基于蛋黄酱的调味汁，包括：a）蛋黄酱芥末酱、b）蓝纹奶酪酱、c）千岛酱和d）海鲜酱，分别接种一种肠出血性大肠杆菌菌株。这些调味汁的样品保存在5℃，并定期检测可检测到的肠出血性大肠杆菌的存活情况。直接平板计数和选择性富集回收均用作检测程序。当通过直接平板计数或选择性富集进行检测时，接种并混入蛋黄酱中并在25℃下储存的大肠杆菌O157:H7菌株在储存72小时后变得无法检测到。接种到蛋黄酱中并在7℃下储存的相同菌株，通过直接平板计数或选择性富集进行检测时，在35天内均可检测到。接种到基于蛋黄酱的调味汁中并保存在5℃的大肠杆菌O157:H7在四种调味汁中的三种中在35天后仍可检测到。在蛋黄酱芥末酱中，肠出血性大肠杆菌的可培养性在3天内丧失。
