Max Rubner-Institute, Federal Research Institute of Nutrition and Food, Department of Safety and Quality of Milk and Fish Products, Hermann-Weigmann Straße 1, D-24103 Kiel, Germany.
J Dairy Sci. 2011 Aug;94(8):3801-10. doi: 10.3168/jds.2011-4318.
Several outbreaks of Cronobacter spp. (Enterobacter sakazakii) have been described as food-borne illness in neonates and infants. Powdered infant formula has been identified as a source of infection, especially in hospital nurseries, where a bulk of formula nutrient is prepared for the whole day and instructions for preparation are not always followed correctly. Neonates who are underweight or immunosuppressed are especially at risk for an E. sakazakii infection. Considering that milk powder is the main ingredient of powdered infant formula, we analyzed the incidence and distribution of E. sakazakii in a milk powder-producing plant. We looked specifically at the spray-drying towers and roller dryers. Selected isolates from samples taken from the environment and final product were typed by pulsed-field gel electrophoresis to investigate the epidemiology of the organism within the production area of the plant. Seven pulsed-field gel electrophoresis types were detected in the spray-drying area, which presumably entered the plant through an aperture for process air and an improperly controlled roller shutter. Furthermore, textile filters for exhaust air of both the spray-drying towers were identified as internal reservoirs of the pathogen. For economic reasons, powder from the textile filters is reintroduced into the product flow; this can contaminate the final product. For the production of milk powder to be used as an ingredient of powdered infant formula, it was suggested to terminate the process of reintroducing the filtered powder into the product flow. A second transmission route was identified in the roller dryer section of the factory. It could be shown that contaminated milk concentrate could pass the process unheated, thus leading to a contamination of the product with E. sakazakii.
已经有几起因 Cronobacter spp.（阪崎肠杆菌）引起的暴发被描述为新生儿和婴儿的食源性疾病。配方奶粉已被确定为感染源，特别是在医院托儿所，那里为全天准备大量的配方营养物质，但制备说明并不总是得到正确遵循。体重不足或免疫功能低下的新生儿特别容易感染 E. sakazakii。考虑到奶粉是配方奶粉的主要成分，我们分析了一家奶粉生产厂中 E. sakazakii 的发病率和分布情况。我们特别关注喷雾干燥塔和滚筒干燥器。从环境和最终产品中采集的样本中选择的分离株通过脉冲场凝胶电泳进行分型，以调查该生产区域内该生物体的流行病学情况。在喷雾干燥区域检测到 7 种脉冲场凝胶电泳类型，这些类型可能通过用于工艺空气的孔和未正确控制的快门进入工厂。此外，喷雾干燥塔的排气用纺织过滤器被确定为病原体的内部储存库。出于经济原因，从纺织过滤器中回收的粉末被重新引入产品流中；这可能会污染最终产品。为了生产用作配方奶粉成分的奶粉，建议终止将过滤粉末重新引入产品流的过程。在工厂的滚筒干燥器部分发现了第二条传输途径。可以证明，污染的牛奶浓缩物可以未经加热通过该过程，从而导致产品受到 E. sakazakii 的污染。
