Scarano Christian, Giacometti Federica, Manfreda Gerardo, Lucchi Alex, Pes Emanuela, Spanu Carlo, De Santis Enrico Pietro Luigi, Serraino Andrea
Department of Veterinary Medicine, University of Sassari, Sassari, Italy.
Department of Veterinary Medical Sciences, University of Bologna, Ozzano Emilia, Italy
Appl Environ Microbiol. 2014 Nov;80(22):7036-41. doi: 10.1128/AEM.02491-14. Epub 2014 Sep 5.
This study aimed to evaluate Arcobacter species contamination of industrial sheep ricotta cheese purchased at retail and to establish if the dairy plant environment may represent a source of contamination. A total of 32 sheep ricotta cheeses (1.5 kg/pack) packed in a modified atmosphere were purchased at retail, and 30 samples were collected in two sampling sessions performed in the cheese factory from surfaces in contact with food and from surfaces not in contact with food. Seven out of 32 samples (21.9%) of ricotta cheese collected at retail tested positive for Arcobacter butzleri at cultural examination; all positive samples were collected during the same sampling and belonged to the same batch. Ten surface samples (33.3%) collected in the dairy plant were positive for A. butzleri. Cluster analysis identified 32 pulsed-field gel electrophoresis (PFGE) patterns. The same PFGE pattern was isolated from more than one ricotta cheese sample, indicating a common source of contamination, while more PFGE patterns could be isolated in single samples, indicating different sources of contamination. The results of the environmental sampling showed that A. butzleri may be commonly isolated from the dairy processing plant investigated and may survive over time, as confirmed by the isolation of the same PFGE pattern in different industrial plant surface samples. Floor contamination may represent a source of A. butzleri spread to different areas of the dairy plant, as demonstrated by isolation of the same PFGE pattern in different production areas. Isolation of the same PFGE pattern from surface samples in the dairy plant and from ricotta cheese purchased at retail showed that plant surfaces may represent a source of A. butzleri postprocessing contamination in cheeses produced in industrial dairy plants.
本研究旨在评估零售购买的工业羊乳清干酪中弓形杆菌属的污染情况，并确定乳制品工厂环境是否可能是污染源。共从零售渠道购买了32份包装在气调包装中的羊乳清干酪（每包1.5千克），并在奶酪工厂进行的两次采样中，从与食品接触的表面和不与食品接触的表面采集了30个样本。在零售渠道收集的32份羊乳清干酪样本中，有7份（21.9%）在培养检查中检测出布氏弓形杆菌呈阳性；所有阳性样本均在同一次采样中收集，且属于同一批次。在乳制品工厂采集的10个表面样本（33.3%）中，布氏弓形杆菌呈阳性。聚类分析确定了32种脉冲场凝胶电泳（PFGE）图谱。从多个羊乳清干酪样本中分离出相同的PFGE图谱，表明存在共同污染源，而在单个样本中可分离出更多PFGE图谱，表明存在不同污染源。环境采样结果表明，在所调查的乳制品加工厂中，布氏弓形杆菌可能普遍存在且能长期存活，不同工业厂房表面样本中分离出相同的PFGE图谱证实了这一点。地板污染可能是布氏弓形杆菌传播到乳制品工厂不同区域的一个来源，不同生产区域分离出相同的PFGE图谱证明了这一点。从乳制品工厂的表面样本和零售购买的羊乳清干酪中分离出相同的PFGE图谱，表明工厂表面可能是工业乳制品厂生产的奶酪在加工后受到布氏弓形杆菌污染的一个来源。
