Melbourne School of Land and Environment, The University of Melbourne, Parkville, Victoria 3010, Australia.
Int J Food Microbiol. 2010 Apr 15;138(3):232-7. doi: 10.1016/j.ijfoodmicro.2010.01.022. Epub 2010 Feb 1.
Minor shoot injury to glasshouse celery, Cos lettuce and chive plants significantly increased the persistence of applied Escherichia coli (P<0.05). After 1 week, mean counts of about 5 log(10) CFU/g decreased to fewer than 0.5 log(10) CFU/g on the uninjured plants, compared to 4 log(10) CFU/g or more on injured plants. By the end of the 3-week long experiments, counts from the uninjured plants were 0.21 log(10) CFU/g or fewer, but 2.8, 2.3 and 5.1 log(10) CFU/g on injured Cos lettuce, celery and chive plants, respectively. A field experiment using Cos lettuce also showed that shoot injury increased E. coli persistence. Counts from the injured plants on days 1, 3, and 7 were, 4.2, 4.1 and 3.3 log(10) CFU/g, respectively, whereas the uninjured plants returned significantly (P<0.05) lower counts on those days, and were 2.8, 2.0 and 1.2 log(10) CFU/g, respectively. These findings reveal that increased E. coli persistence on injured tissue is common to different vegetables and can occur in the glasshouse and the field. The implications of this study on vegetable production practices are presented.
温室芹菜、生菜和韭菜植株的轻微茎叶损伤会显著增加施用于植株的大肠杆菌的持久性（P<0.05）。1 周后，未受伤植株上的大肠杆菌数量从约 5 log(10) CFU/g 减少到少于 0.5 log(10) CFU/g，而受伤植株上的大肠杆菌数量仍保持在 4 log(10) CFU/g 或更高。在为期 3 周的实验结束时，未受伤植株上的细菌数量为 0.21 log(10) CFU/g 或更少，但受伤的生菜、芹菜和韭菜植株上的细菌数量分别为 2.8、2.3 和 5.1 log(10) CFU/g。在生菜上进行的田间试验也表明，茎叶损伤会增加大肠杆菌的持久性。受伤植株在第 1、3 和 7 天的细菌数量分别为 4.2、4.1 和 3.3 log(10) CFU/g，而未受伤植株在这些天数的细菌数量显著（P<0.05）较低，分别为 2.8、2.0 和 1.2 log(10) CFU/g。这些发现表明，受伤组织中大肠杆菌持久性的增加在不同蔬菜中是普遍存在的，并且可以在温室和田间发生。本研究对蔬菜生产实践的意义也在文中提出。
