The majority of cases of listeriosis are associated with the consumption of contaminated food. Some strains of Listeria monocytogenes can persist over months or years in meat processing plants increasing the risk of product contamination. The presence of L. monocytogenes was examined in 10 dry-cured ham processing facilities. A total of 1801 samples were collected from environment and equipment, during processing (1095) and after cleaning and disinfection (706). These samples were taken from non-food contact (736) and food contact (1065) surfaces. In addition, 204 samples from ham surfaces were also analysed. Prevalence varied from 6% to 34% among facilities, and was higher during processing than after cleaning and disinfection (24.8% vs 11.0%) and from non-food than from food contact surfaces (22.6% vs 17.4%). L. monocytogenes serotype 1/2a was predominant (53.9%), followed by 1/2c (26.0%) and 1/2b (15.3%) and less frequently 4b (4.8%). A total of 142 different pulsotypes were registered. Potential persistent L. monocytogenes strains were isolated in 9 out the 10 facilities, with no more than 6 pulsotypes in a given plant. Two pulsotypes were common in different installations, detected before and after cleaning and disinfection, highlighting the importance of monitoring the presence of this pathogen in dry-cured ham processing environments.

大多数李斯特菌病病例与食用受污染的食物有关。一些单核细胞增生李斯特菌菌株可以在肉类加工厂中持续数月或数年，从而增加产品污染的风险。在10个干腌火腿加工设施中检查了单核细胞增生李斯特菌的存在。在处理期间（1095）以及清洁和消毒之后（706），从环境和设备中总共收集了1801个样品。这些样本取自非食品接触（736）和食品接触（1065）的表面。此外，还分析了火腿表面的204个样品。设施中的患病率从6％到34％不等，并且在加工过程中高于清洁和消毒后的患病率（24.8％vs11.0％）和来自非食物的食物比来自食物接触表面的食物（22.6％和17.4％）。单核细胞增生李斯特菌血清型1 / 2a占主导地位（53.9％），其次是1 / 2c（26.0％）和1 / 2b（15.3％），少见的是4b（4.8％）。总共登记了142种不同的脉冲型。潜在持久L. 菌菌株在9中分离出的10个设施，在给定的植物不超过6个pulsotypes。两种脉冲型在不同的装置中很常见，分别在清洁和消毒前后进行检测，这突出了在干腌火腿加工环境中监测这种病原体的存在的重要性。