Chantarapanont W, Slutsker L, Tauxe R V, Beuchat L R
Center for Food Safety and Quality Enhancement, Department of Food Science and Technology, University of Georgia, Griffin 30223-1797, USA.
J Food Prot. 2000 Jan;63(1):36-43. doi: 10.4315/0362-028x-63.1.36.
The inside of a hen's egg, once considered sterile, is now known to occasionally harbor Salmonella Enteritidis. At least two recent outbreaks of salmonellosis in which Salmonella Enteritidis PT34 was involved have been associated with hard-cooked eggs. This study was undertaken to compare D56 degrees C values of Salmonella Senftenberg 775W and six strains of Salmonella Enteritidis isolated from outbreaks associated with eggs. D56 degrees C values for Salmonella Enteritidis in liquid egg yolk ranged from 5.14 to 7.39 min; the D56 degrees C value for Salmonella Senftenberg was 19.96 min. The two PT34 strains from outbreaks associated with hard-cooked eggs did not exhibit significantly higher resistance to heat compared with two PT4 strains and one strain each of PT8 and PT13a. A PT4 strain and a PT34 strain of Salmonella Enteritidis were separately inoculated (10(7) to 10(8) CFU) into the yolk of medium and extra large shell eggs at 10 and 21 degrees C, and survival was monitored using two cooking methods: (i) placing eggs in water at 23 degrees C, heating to 100 degrees C, removing from heat, and holding for 15 min (American Egg Board method) and (ii) placing eggs in water at 100 degrees C, then holding for 15 min at this temperature. Within the 15-min holding periods, inactivation was more rapid using the method recommended by the American Egg Board compared with method 2. Within each cooking method, inactivation was most rapid in medium eggs initially at 21 degrees C. The PT4 strain survived in yolk of extra large eggs initially at 10 degrees C when eggs were held in boiling water 9 min using method 2. The final temperature of the yolk in these eggs was 62.3 +/- 2 degrees C. Of the two methods evaluated for hard cooking eggs, the American Egg Board method is clearly most effective in killing Salmonella Enteritidis in the yolk.
曾经被认为无菌的鸡蛋内部，现在已知偶尔会携带肠炎沙门氏菌。最近至少有两起涉及肠炎沙门氏菌PT34的沙门氏菌病暴发与全熟鸡蛋有关。本研究旨在比较森夫滕贝格沙门氏菌775W和从与鸡蛋相关的疫情中分离出的六株肠炎沙门氏菌的D56℃值。液态蛋黄中肠炎沙门氏菌的D56℃值范围为5.14至7.39分钟；森夫滕贝格沙门氏菌的D56℃值为19.96分钟。与两株PT4菌株以及各一株PT8和PT13a菌株相比，从与全熟鸡蛋相关的疫情中分离出的两株PT34菌株对热的抗性并未显著更高。将一株肠炎沙门氏菌PT4菌株和一株PT34菌株分别以10⁷至10⁸CFU接种到中号和特大号带壳鸡蛋的蛋黄中，分别置于10℃和21℃，并使用两种烹饪方法监测其存活情况：(i) 将鸡蛋放入23℃的水中，加热至100℃，关火并保持15分钟（美国鸡蛋委员会方法）；(ii) 将鸡蛋放入100℃的水中，然后在此温度下保持15分钟。在15分钟的保持期内，与方法2相比，使用美国鸡蛋委员会推荐的方法时灭活速度更快。在每种烹饪方法中，最初在21℃的中号鸡蛋中灭活速度最快。当使用方法2将鸡蛋在沸水中保持9分钟时，PT4菌株在最初处于10℃的特大号鸡蛋的蛋黄中存活。这些鸡蛋蛋黄的最终温度为62.3±2℃。在评估的两种全熟鸡蛋烹饪方法中，美国鸡蛋委员会方法显然在杀死蛋黄中的肠炎沙门氏菌方面最有效。
