Technology and Food Science Unit-Food Safety, Institute for Agricultural and Fisheries Research-ILVO, Melle, Belgium.
Foodborne Pathog Dis. 2013 Jun;10(6):485-91. doi: 10.1089/fpd.2012.1386. Epub 2013 Apr 24.
The survival of Salmonella enterica serovar Thompson and Escherichia coli O157 was investigated on growing butterhead lettuce plants in the plant-growth chamber and greenhouse. All inoculation tests were made under conditions that approximate the greenhouse conditions for butterhead lettuce cultivation in Flanders (Belgium). The survival and proliferation of the pathogens on the leaves was determined at days 0, 4, and 8 after inoculation using standard plating techniques on selective medium. In the growth chamber, the extent to which both pathogens were able to multiply on the lettuce leaves was influenced by crop stage and leaf age. On young plants, the older leaves supported pathogen survival better. On nearly mature plants, pathogen population sizes were significantly higher on the old and young leaves compared with middle-aged leaves (p<0.001). In the greenhouse, the environmental regimen with high fluctuations in temperature and relative humidity was less conducive to the survival of E. coli O157, though its survival on nearly mature lettuce was enhanced by overhead irrigation. The moist conditions between the folded inner leaves are likely contributing to the survival of enteric pathogens in the lettuce head. Butterhead lettuce grown in greenhouses with a sprinkle irrigation system may present a potential health hazard when contaminated near harvest. Experimental design (growth chamber versus greenhouse) largely influences enteric pathogen behavior on growing lettuce plants.
研究了生长在植物生长室和温室中的奶油生菜植株上的肠炎沙门氏菌血清型汤普森和大肠杆菌 O157 的存活情况。所有接种试验都是在接近佛兰德（比利时）奶油生菜种植温室条件下进行的。在接种后 0、4 和 8 天，使用选择性培养基上的标准平板技术，确定了病原体在叶片上的存活和增殖情况。在生长室中，两种病原体在生菜叶片上繁殖的程度受到作物阶段和叶片年龄的影响。在幼株上，较老的叶片更有利于病原体的存活。在接近成熟的植株上，与中年叶片相比，老叶和嫩叶上的病原体种群数量显著更高（p<0.001）。在温室中，温度和相对湿度波动较大的环境方案不利于大肠杆菌 O157 的存活，尽管其在接近成熟的生菜上的存活因头顶灌溉而增强。折叠内叶之间的潮湿条件可能有助于生菜头内肠道病原体的存活。当受污染的生菜在收获附近生长时，带有喷灌系统的温室中的奶油生菜可能会带来潜在的健康危害。实验设计（生长室与温室）在很大程度上影响了生长中生菜植株上肠道病原体的行为。
