Abstract：
The production of whole-liquid eggs is of significant economic and nutritional importance. This study aimed to assess the phenotypic and genotypic diversity of mesophilic aerobic spore-forming bacteria (n = 200) isolated from pasteurized whole liquid egg and liquid egg yolk. The majority of the isolates were identified as belonging to the genera Bacillus (86 %), followed by Brevibacillus (10 %) and Lysinibacillus (4 %). For the phenotypic characterization, isolates were subjected to various heat shocks, with the most significant reductions observed at 80 °C/30 min and 90 °C/10 min for isolates recovered from raw materials. On the other hand, the decrease was similar for isolates recovered from raw material and final product at 100 °C/5 min and 110 °C/5 min. Genotypic genes related to heat resistance (cdnL, spoVAD, dacB, clpC, dnaK, and yitF/Tn1546) were examined for genotypic characterization. The dnaK gene showed a positive correlation with the highest thermal condition tested (110 °C/5 min), while 100 °C/5 min had the highest number of positively correlated genes (clpC, cdnL, yitF/Tn1546, and spoVAD). Whole Genome Sequencing of four strains revealed genes related to sporulation, structure formation, initiation and regulation, stress response, and DNA repair in vegetative cells. The findings of this study indicate that these mesophilic aerobic spore-forming bacteria may adopt several strategies to persist through the process and reach the final product. As the inactivation of these microorganisms during egg processing is challenging, preventing raw materials contamination and their establishment in processing premises must be reinforced.
摘要：
全液体蛋的生产具有重要的经济和营养重要性。本研究旨在评估从巴氏杀菌的全液卵和液蛋黄中分离出的嗜温性需氧孢子形成细菌（n=200）的表型和基因型多样性。大多数分离物被鉴定为属于芽孢杆菌属（86％），其次是短芽孢杆菌（10％）和溶血芽孢杆菌（4％）。对于表型表征，分离株受到各种热冲击，对于从原材料中回收的分离物，在80°C/30分钟和90°C/10分钟时观察到最显着的降低。另一方面,对于在100°C/5分钟和110°C/5分钟下从原料和最终产物中回收的分离物,降低类似。与耐热性相关的基因型基因(cdnL，spoVAD,dacb,clpC,dnaK,和yitF/Tn1546）进行了基因型鉴定。dnaK基因与测试的最高热条件（110°C/5分钟）呈正相关，而100°C/5分钟的正相关基因数量最高(clpC，cdnL,yitF/Tn1546和spoVAD)。四个菌株的全基因组测序揭示了与孢子形成相关的基因，结构形成,启动和调节，应激反应，和营养细胞中的DNA修复。这项研究的结果表明，这些嗜温需氧孢子形成细菌可能会采取几种策略来持续整个过程并达到最终产品。由于在鸡蛋加工过程中这些微生物的失活具有挑战性，必须加强防止原材料污染及其在加工场所的建立。
