Colás-Medà Pilar, Viñas Inmaculada, Oliveira Márcia, Anguera Marina, Serrano Jose C E, Abadias Maribel
Food Technology Department, University of Lleida, XaRTA-Postharvest, Agrotecnio Center, Rovira Roure, 191, 25198, Lleida, Catalonia, Spain.
IRTA, XaRTA-Postharvest, Edifici Fruitcentre, Parc Científic i Tecnològic Agroalimentari de Lleida, Parc de Gardeny, 25003, Lleida, Catalonia, Spain.
Food Microbiol. 2017 Apr;62:275-281. doi: 10.1016/j.fm.2016.10.016. Epub 2016 Oct 13.
Survival and virulence of foodborne pathogens can be influenced by environmental factors such as the intrinsic properties of food as well as the extrinsic properties that contribute to food shelf life (e.g., temperature and gas atmosphere). The direct contribution of food matrix characteristics on the survival of L. monocytogenes during fresh-cut fruit shelf life is not very well understood. In addition, the gastrointestinal tract is the primary route of listeriosis infection and penetration of the intestinal epithelial cell barrier is the first step in the infection process. Hence, the pathogenic potential of L. monocytogenes, measured as the capability for the organism to survive a simulated gastrointestinal tract and the proportion of cells able to subsequently adhere to and invade differentiated Caco-2 cells, subjected to fresh-cut pear and melon shelf life, was investigated. Samples were inoculated, stored at 10 °C for 7 days and evaluated after inoculation and again after 2 and 7 days of storage. A decrease in L. monocytogenes' capacity to survive a simulated gastrointestinal tract was observed with increasing storage time, regardless of the fruit matrix evaluated. Furthermore, L. monocytogenes placed on fresh-cut pear and melon was subjected to an attachment and invasion assay after crossing the simulated gastrointestinal tract. After inoculation, pathogen on fresh-cut pear showed 5-fold more capacity to adhere to Caco-2 cells than pathogen on fresh-cut melon. After 2 days of storage, L. monocytogenes grown on fresh-cut melon showed similar adhesive capacity (1.11%) than cells grown on pear (1.83%), but cells grown on melon had the higher invasive capacity (0.0093%). We can conclude that minimally processed melon could represent a more important hazard than pear under the studied shelf life.
食源性病原体的存活和毒力会受到环境因素的影响，如食物的内在特性以及影响食物保质期的外在特性（如温度和气体氛围）。鲜切水果保质期内食物基质特性对单核细胞增生李斯特菌存活的直接影响尚未得到很好的理解。此外，胃肠道是李斯特菌病感染的主要途径，肠道上皮细胞屏障的穿透是感染过程的第一步。因此，研究了以单核细胞增生李斯特菌在模拟胃肠道中存活的能力以及随后能够黏附和侵袭分化的Caco-2细胞的细胞比例来衡量的单核细胞增生李斯特菌的致病潜力，该菌分别置于鲜切梨和甜瓜的保质期环境中。接种样品后，在10°C下储存7天，并在接种后以及储存2天和7天后进行评估。无论评估的水果基质如何，随着储存时间的增加，均观察到单核细胞增生李斯特菌在模拟胃肠道中存活的能力下降。此外，置于鲜切梨和甜瓜上的单核细胞增生李斯特菌在穿过模拟胃肠道后进行黏附与侵袭试验。接种后，鲜切梨上的病原体黏附Caco-2细胞的能力比鲜切甜瓜上的病原体高5倍。储存2天后，在鲜切甜瓜上生长的单核细胞增生李斯特菌显示出与在梨上生长的细胞相似的黏附能力（1.11%），但在甜瓜上生长的细胞具有更高的侵袭能力（0.0093%）。我们可以得出结论，在研究的保质期内，最少加工的甜瓜可能比梨构成更重要的危害。
