U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Environmental Microbiology and Food Safety Laboratory, Beltsville, Maryland 20705, USA; Department of Nutrition and Food Science, University of Maryland, College Park, Maryland 20742, USA.
U.S. Department of Agriculture, Agricultural Research Service, Beltsville Agricultural Research Center, Environmental Microbiology and Food Safety Laboratory, Beltsville, Maryland 20705, USA.
J Food Prot. 2014 Mar;77(3):365-70. doi: 10.4315/0362-028X.JFP-13-307.
Salmonella internalization in tomatoes during postharvest handling is a major food safety concern. This study was conducted to determine the effect of immersion time, immersion depth, and temperature differential between bacterial suspension and tomato pulp on the internalization of Salmonella enterica in tomato fruits. The effect of storage temperature and duration on the survival and growth of internalized Salmonella cells was also evaluated. Overall, immersion time significantly affected the incidence and extent of S. enterica internalization (P < 0.0001), with a linear correlation between immersion time and Salmonella internalization. The depth of Salmonella internalization in tomato tissues also increased with increasing immersion time. Immersion time also significantly influenced the degree to which the temperature differential affected Salmonella internalization. With an immersion time of 2 min, the temperature differential had no significant effect on Salmonella internalization (P = 0.2536). However, with an immersion time of 15 min, a significantly larger Salmonella population became internalized in tomatoes immersed in solutions with a -30°F (-16.7°C) temperature differential. Internalized S. enterica cells persisted in the core tissues during 14 days of storage. Strain type and storage duration significantly affected (P < 0.05) both the frequency detected and the population of internalized Salmonella recovered, but storage temperatures of 55 to 70°F (12.8 to 21.1°C) did not (P > 0.05). These findings indicate the importance of preventing pathogen internalization during postharvest handling.
在采后处理过程中，沙门氏菌在番茄中的内化是一个主要的食品安全问题。本研究旨在确定浸泡时间、浸泡深度和菌悬液与番茄果肉之间的温度差对食源性致病菌沙门氏菌在番茄果实中内化的影响。还评估了储存温度和时间对内化沙门氏菌细胞存活和生长的影响。总体而言，浸泡时间显著影响沙门氏菌内化的发生率和程度（P < 0.0001），浸泡时间与沙门氏菌内化之间呈线性相关。沙门氏菌在番茄组织中的内化深度也随浸泡时间的增加而增加。浸泡时间还显著影响温度差对内化沙门氏菌的影响程度。在浸泡时间为 2 分钟的情况下，温度差对内化沙门氏菌没有显著影响（P = 0.2536）。然而，在浸泡时间为 15 分钟的情况下，浸泡在-30°F（-16.7°C）温差溶液中的番茄中，有明显更大的沙门氏菌种群内化。在 14 天的储存期内，内化的 S. enterica 细胞在核心组织中持续存在。菌株类型和储存时间显著影响（P < 0.05）检测到的频率和回收的内化沙门氏菌的数量，但储存温度为 55 至 70°F（12.8 至 21.1°C）时没有影响（P > 0.05）。这些发现表明在采后处理过程中防止病原体内化的重要性。
