School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, Australia.
Vet Res. 2019 Jul 30;50(1):58. doi: 10.1186/s13567-019-0677-4.
Human cases of salmonellosis are frequently liked with the consumption of contaminated table eggs. Recently, there has been an increase in consumer demand for cage-free eggs precipitating the need for a greater understanding of Salmonella dynamics in free-range production systems. A longitudinal study was conducted to determine the points in production where birds are most likely to be exposed to Salmonella and where the risk of egg contamination is highest. In this study, two free-range flocks were sampled from hatch to the end of production. At hatch, all chicks were Salmonella negative and remained negative during rearing. During production, the proportion of positive samples was low on both farms. Salmonella positive samples were detected intermittently for Flock A. Dust, nest box, and egg belt swabs had the highest proportion of positive samples and highest overall loads of Salmonella. The egg grading floor was swabbed at different points following the processing of eggs from Flock A. Only the suction cups that handle eggs prior to egg washing tested positive for Salmonella. Swabs collected from machinery handling eggs after washing were Salmonella negative. During production, positive samples from Flock B were observed at only single time point. Dust has been implicated as a source of Salmonella that can lead to flock to flock contamination. Bulk dust samples were collected and tested for Salmonella. The proportion of positive dust samples was low and is likely due to physical parameters which are not likely to support the survival of Salmonella in the environment.
人类沙门氏菌病的病例常与食用受污染的食用蛋有关。最近，消费者对无笼蛋的需求增加，这促使人们需要更好地了解自由放养生产系统中的沙门氏菌动态。本研究进行了一项纵向研究，以确定鸟类最有可能接触沙门氏菌的生产点，以及鸡蛋污染风险最高的地方。在这项研究中，从孵化到生产结束，对两个自由放养的鸡群进行了采样。孵化时，所有雏鸡均为沙门氏菌阴性，在饲养过程中一直保持阴性。在生产过程中，两个农场的阳性样本比例都很低。A 鸡群的间歇性检测到了阳性样本。灰尘、巢箱和蛋带拭子的阳性样本比例最高，且沙门氏菌的总负荷最高。对 A 鸡群的鸡蛋进行处理后，在不同时间点对鸡蛋分级地板进行了拭子取样。只有在鸡蛋清洗之前处理鸡蛋的吸盘检测到了沙门氏菌阳性。清洗后处理鸡蛋的机械上采集的拭子为沙门氏菌阴性。在生产过程中，仅在一个时间点观察到 B 鸡群的阳性样本。灰尘已被认为是沙门氏菌的来源，可导致鸡群之间的污染。收集并测试了散装灰尘样本。阳性灰尘样本的比例较低，这可能是由于物理参数不太可能支持环境中沙门氏菌的存活。
