Hygiene and Zoonoses Department, Faculty of Veterinary Medicine, Mansoura University, 35516 Mansoura, Egypt.
Institute for Animal Nutrition, University of Veterinary Medicine Hanover, Foundation, 30173 Hannover, Germany.
Poult Sci. 2023 Aug;102(8):102788. doi: 10.1016/j.psj.2023.102788. Epub 2023 May 24.
Broiler meat is the predominant source of Salmonella as a foodborne pathogen. Several control strategies have focused on the reduction of Salmonella spp. levels at different production stages. However, the persistence of Salmonella between consecutive flocks is still of great concern. This study was designed to understand the cause of reinfection in broiler flocks due to survival of Salmonella in feeding lines of related matrices. Salmonella (S.) Enteritidis, S. Infantis, and S. Typhimurium isolated from broiler farms in North-West Germany were used. Four types of matrices (phosphate buffer saline (PBS), dietary plant fat, fat with feed mixture, and feed) were applied to evaluate Salmonella survival (with the initial dose about 8.0 log CFU/mL) during a simulation of 4 production cycles. To evaluate the growth and survival status of Salmonella ISO 6579-1:2017 were performed (quantitatively by plate count method (PCM) and most probable number method (MPN)) and qualitatively) at 5 defined time points (-7, 0, 4, 7, and 35 d). In all matrices and for the 3 serovars, the Salmonella count decreased at the end of the fourth cycle in comparison to the beginning of the experimental infection, and was still cultivated except for fat matrix. The PBS matrices showed the highest survival level of Salmonella and did not decline drastically by the end of the fourth cycle (5.93 ± 0.00, 5.87 ± 0.02, 5.73 ± 0.05 log CFU/mL, respectively). However, the fat matrices showed the lowest survival level for the 3 isolates at d 35 since the first cycle (0 log CFU/mL using PCM). Regarding the fat-feed mixture, and feed matrices, there was a fluctuation in the survival rate of Salmonella (all serovars) within each cycle. For the qualitative method, the 3 serovars persisted in all matrices until the end of the fourth cycle except for fat matrices. The present study highlights the ability of Salmonella to survive for a long time in different temperatures and matrices despite efficient cleaning and disinfection processes in the feeding lines, which may influence reinfection with Salmonella in poultry houses.
鸡肉是食源性致病菌沙门氏菌的主要来源。 已经有几种控制策略集中在降低不同生产阶段的沙门氏菌水平上。 然而，连续批次之间沙门氏菌的持续存在仍然令人非常关注。 本研究旨在了解由于与相关基质的进料线相关的沙门氏菌在饲料线中存活而导致肉鸡群重新感染的原因。 使用了从德国西北部肉鸡养殖场分离的沙门氏菌（S. Enteritidis、S. Infantis 和 S. Typhimurium）。 应用了四种基质（磷酸盐缓冲盐水（PBS）、饮食植物脂肪、含饲料混合物的脂肪和饲料）来评估沙门氏菌在 4 个生产周期模拟中的存活情况（初始剂量约为 8.0 log CFU/mL）。 为了评估沙门氏菌的生长和存活状态，根据 ISO 6579-1:2017 进行了定量（平板计数法（PCM）和最可能数法（MPN））和定性）在 5 个定义的时间点（-7、0、4、7 和 35 d）。 在所有基质和 3 种血清型中，与实验感染开始时相比，在第四个周期结束时沙门氏菌的数量减少，除了脂肪基质外，仍可培养。 PBS 基质显示出沙门氏菌的最高存活水平，并且在第四个周期结束时没有急剧下降（分别为 5.93 ± 0.00、5.87 ± 0.02、5.73 ± 0.05 log CFU/mL）。 然而，在第一个周期中，脂肪基质对 3 种分离株的存活水平最低（使用 PCM 为 0 log CFU/mL）在第 35 天。 关于脂肪-饲料混合物和饲料基质，沙门氏菌的存活率在每个周期内都有波动（所有血清型）。 对于定性方法，除了脂肪基质外，3 种血清型在所有基质中均能存活到第四个周期结束。 本研究强调了沙门氏菌在不同温度和基质中长时间存活的能力，尽管在进料线中进行了有效的清洁和消毒过程，但这可能会影响禽舍中沙门氏菌的重新感染。
