Smith D P, Musgrove M T
USDA, Agricultural Research Service, Richard B. Russell Research Center, Athens, GA 30605, USA.
Poult Sci. 2008 Aug;87(8):1659-61. doi: 10.3382/ps.2007-00528.
Presence of blood spots in eggs has been correlated with a greater rate of Salmonella Enteritidis contamination. Therefore, this study was conducted to determine whether Salmonella inoculated into egg albumen with naturally occurring blood spots would survive or grow. In each of 3 trials, white shell table eggs with blood spots were collected from a commercial egg-processing plant after candling. In each trial, eggs were broken out, and approximately 4 mL of clear albumen (CLEAR) and 4 mL of bloody albumen (BLOOD) from each of 10 eggs were placed in sterile test tubes and inoculated with a nalidixic acid-resistant Salmonella Typhimurium. For inoculation, 0.1 mL of the Salmonella Typhimurium suspension (containing 7.1, 7.7, or 7.0 log cfu/mL in trials 1 to 3, respectively) was added to each tube. Tube contents were mixed and incubated at 25 degrees C for 24 h. Immediately after inoculation (0 h) and again after 24 h, 0.1 mL from each tube was plated onto Brilliant Green-Sulfa agar with 200 ppm nalidixic acid and incubated at 37 degrees C for 24 h. Results are reported as log colony-forming units per milliliter of albumen. No significant differences (P < 0.05) in mean Salmonella Typhimurium counts were found between CLEAR or BLOOD samples at 0 h (5.6 vs. 5.8, respectively), indicating that initial inoculation levels were consistent between treatments. After 24 h, CLEAR samples were slightly but significantly lower than BLOOD samples for Salmonella Typhimurium (6.5 vs. 6.8, respectively). Salmonella Typhimurium numbers increase somewhat in albumen with or without blood, but slightly greater numbers are produced in albumen with blood spots. In this experiment, blood in the albumen of table eggs contributed to the survival and growth of Salmonella Typhimurium inoculated into egg albumen.
鸡蛋中出现血斑与肠炎沙门氏菌污染率较高有关。因此，本研究旨在确定接种到带有自然血斑的蛋清中的沙门氏菌是否会存活或生长。在3次试验中的每次试验中，通过照蛋从一家商业鸡蛋加工厂收集带有血斑的白壳食用蛋。在每次试验中，将鸡蛋打破，从10个鸡蛋中分别取出约4毫升清蛋清（CLEAR）和4毫升带血蛋清（BLOOD），放入无菌试管中，并用耐萘啶酸的鼠伤寒沙门氏菌接种。接种时，向每个试管中加入0.1毫升鼠伤寒沙门氏菌悬液（在试验1至3中分别含有7.1、7.7或7.0 log cfu/mL）。将试管内容物混合并在25℃下孵育24小时。接种后立即（0小时）以及24小时后，从每个试管中取出0.1毫升接种到含有200 ppm萘啶酸的亮绿磺胺琼脂平板上，并在37℃下孵育24小时。结果以每毫升蛋清中的对数菌落形成单位表示。在0小时时，清蛋清或带血蛋清样品中的鼠伤寒沙门氏菌平均计数没有显著差异（P < 0.05）（分别为5.6和5.8），这表明各处理之间的初始接种水平一致。24小时后，清蛋清样品中的鼠伤寒沙门氏菌数量略低于但显著低于带血蛋清样品（分别为6.5和6.8）。鼠伤寒沙门氏菌在有血或无血的蛋清中数量均有所增加，但在有血斑的蛋清中数量增加略多。在本实验中，食用蛋蛋清中的血液有助于接种到蛋清中的鼠伤寒沙门氏菌的存活和生长。
