De Reu Koen, Grijspeerdt Koen, Heyndrickx Marc, Messens Winy, Uyttendaele Mieke, Debevere Johan, Herman Lieve
Department of Animal Product Quality and Transformation Technology, Ministry of the Flemish Community, Agricultural Research Centre, Brusselsesteenweg 370, 9090 Melle, Belgium.
J Food Prot. 2006 Jul;69(7):1539-45. doi: 10.4315/0362-028x-69.7.1539.
Shells of agar-filled and whole eggs were inoculated with 10(3) to 10(4) CFU of Salmonella enterica serovar Enteritidis per eggshell. The agar-filled eggs were used to study bacterial eggshell penetration, and the whole egg results were used to characterize contamination of the egg contents. In each group, half of the eggs were stored for 21 days at 20 degrees C and 60% relative humidity (RH), and the other half was stored for 24 h at 6 degrees C and then for 20 days at 20 degrees C. The latter conditions resulted in condensation on the eggshell for 30 min from the moment the eggs were placed in the 20 degrees C chamber. Taking into account the ages at which hens were studied (39, 53, and 67 weeks), an average of 62% of the eggshells with condensate were penetrated compared with 43% for the control group; this difference was significant (P < 0.01). No significant difference in whole egg contamination was found; 18% of the control eggs were contaminated compared with 22% of the condensate eggs. Whole egg contamination was significantly higher for eggs from the hens at an older age (67 weeks). This difference probably was not due to a higher penetration potential because differences were not observed for the corresponding agar-filled eggs. Condensation on the eggshell seemed to encourage bacterial penetration of the eggshell but had a smaller impact on whole egg contamination.
每个蛋壳接种10³至10⁴CFU肠炎沙门氏菌肠炎血清型菌液，分别接种于琼脂填充蛋和全蛋。琼脂填充蛋用于研究细菌穿透蛋壳的情况，全蛋结果用于表征蛋液污染情况。每组中，一半鸡蛋在20℃、相对湿度60%（RH）下储存21天，另一半在6℃下储存24小时，然后在20℃下储存20天。后一种条件下，从鸡蛋放入20℃环境开始，蛋壳上会凝结30分钟。考虑到所研究母鸡的年龄（39、53和67周），有凝结水的蛋壳平均62%被穿透，而对照组为43%；这种差异具有显著性（P<0.01）。全蛋污染方面未发现显著差异；对照组18%的鸡蛋被污染，有凝结水的鸡蛋为22%。67周龄母鸡所产鸡蛋的全蛋污染显著更高。这种差异可能并非由于穿透可能性更高，因为相应的琼脂填充蛋未观察到差异。蛋壳上的凝结似乎会促进细菌穿透蛋壳，但对全蛋污染的影响较小。
