Dreux N, Albagnac C, Carlin F, Morris C E, Nguyen-The C
UMR408 Sécurité et Qualité des Produits d'Origine Végétale, INRA, Université d'Avignon, F-84000 Avignon, France.
J Appl Microbiol. 2007 Nov;103(5):1821-7. doi: 10.1111/j.1365-2672.2007.03419.x.
To investigate the population dynamics of Listeria monocytogenes and Listeria innocua on the aerial surfaces of parsley.
Under 100% relative humidity (RH) in laboratory and regardless of the inoculum tested (10(3)-10(8) CFU per leaf), counts of L. monocytogenes EGDe, LO28, LmP60 and L. innocua CIP 80-12 tended towards approx. 10(5) CFU per leaf. Under low RH, Listeria spp. populations declined regardless to the inoculum size (10(4)-10(8) CFU per leaf). L. innocua CIP 80-12 survived slightly better than L. monocytogenes in the laboratory and was used in field cultures. Under field cultures, counts of L. innocua decreased more rapidly than in the laboratory, representing a decrease of 9 log(10) in 2 days in field conditions compared to a decrease of 4.5 log(10) in 8 days in the laboratory. Counts of L. innocua on tunnel parsley cultures were always higher (at least by 100 times) than those on unprotected parsley culture.
Even with a high inoculum and under protected conditions (i.e. plastic tunnels), population of L. monocytogenes on the surface of parsley on the field would decrease by several log(10) scales within 2 days.
Direct contamination of aerial surfaces of parsley with L. monocytogenes (i.e. through contaminated irrigation water) will not lead to contaminated produce unless it occurs very shortly before harvest.
研究单核细胞增生李斯特菌和无害李斯特菌在欧芹气生表面的种群动态。
在实验室100%相对湿度（RH）条件下，无论测试的接种量如何（每片叶子10³ - 10⁸CFU），单核细胞增生李斯特菌EGDe、LO28、LmP60和无害李斯特菌CIP 80 - 12的数量趋向于约每片叶子10⁵CFU。在低相对湿度下，李斯特菌属种群数量无论接种量大小（每片叶子10⁴ - 10⁸CFU）都会下降。无害李斯特菌CIP 80 - 12在实验室中的存活情况略优于单核细胞增生李斯特菌，并用于田间培养。在田间培养条件下，无害李斯特菌的数量下降速度比在实验室中更快，在田间条件下2天内减少了9个对数单位（log₁₀），而在实验室中8天内减少了4.5个对数单位（log₁₀）。隧道栽培的欧芹上无害李斯特菌的数量总是比未保护的欧芹栽培上的数量高（至少高100倍）。
即使接种量很高且在保护条件下（即塑料隧道），田间欧芹表面的单核细胞增生李斯特菌数量在2天内也会减少几个对数单位（log₁₀）。
单核细胞增生李斯特菌直接污染欧芹的气生表面（即通过受污染的灌溉水）不会导致农产品受污染，除非在收获前不久发生污染。
