Nowak Bernhard, von Müffling Theda, Chaunchom Sujate, Hartung Jörg
Institute for Food Quality and Food Safety, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173 Hannover, Germany.
Int J Food Microbiol. 2007 Apr 20;115(3):259-67. doi: 10.1016/j.ijfoodmicro.2006.10.045. Epub 2007 Jan 12.
An antibody ELISA test and a PCR method for identifying the risk of Salmonella contamination were compared in a field study on the same lots of animals in a slaughterhouse. The results were compared to investigations carried out on two farms with different prevalences of Salmonella antibody-positive animals. Salmonella antibody ELISA testing was carried out on all 383 meat juice samples derived from the diaphragm pillar muscle of each pig. Salmonella DNA analysis was performed by PCR technique on small intestine samples with lymph nodes from all 383 pigs, and on tonsils from the last 129 pigs. The 383 animals tested came from 32 different pig farms. Furthermore, the herd antibody blood serum status against Salmonella spp. of weaners was determined on two selected pig fattening farms, one with low and one with high seroprevalence in meat juice. A total of 7.0% (ELISA cut-off OD% > or =40) of the slaughtered pigs from 6 of 32 fattening farms were seropositive. Salmonella DNA was found in 16.4% of the jejunum/lymph nodes (383 animals) and in 15.5% of the tonsils (129 animals). Salmonella DNA was found in the jejunum/lymph nodes of 41% of the seropositive pigs. However, serotitres were also positive in only 17.5% of all pigs positive in the jejunum DNA test. Two farms were selected for further investigation: farm 13 (F13), with a high prevalence of seropositive pigs, 29.0%, Category II; and F11, with 9.4%, Category I. However, categorization according to the blood serum tests of the fattening pigs after on-farm testing was very different: F13 had 5% positive animals (Category I); and F11, 23.3% (Category II). The study led to the following results and recommendations: First, ELISA tests are useful for the detection of farms that are regularly contaminated with Salmonella, but such tests cannot give information on the infectious status of a single animal (or a group) at the point of slaughter. Second, it is crucial that management measures are taken to prevent the spread of infections by trade and transport: piglets should be supplied exclusively by a single, well-known producer, and finishers should be tested serologically on farm before going to slaughter. Third, ELISA tests and the PCR method are suitable for the detection of Salmonella and are recommended as analytical tools for all pork quality control programmes. Fourth, animals from suspicious farms should always be slaughtered at the end of the slaughter day, followed by thorough cleaning and disinfection.
在一家屠宰场对同一批次动物进行的实地研究中，比较了用于鉴定沙门氏菌污染风险的抗体ELISA检测和PCR方法。将结果与在两个沙门氏菌抗体阳性动物患病率不同的农场进行的调查结果进行了比较。对每头猪膈肌柱肌肉的所有383份肉汁样本进行了沙门氏菌抗体ELISA检测。采用PCR技术对所有383头猪的带淋巴结小肠样本以及最后129头猪的扁桃体样本进行了沙门氏菌DNA分析。所检测的383只动物来自32个不同的养猪场。此外，在两个选定的育肥猪场测定了断奶仔猪针对沙门氏菌属的群体抗体血清状态，其中一个猪场肉汁中的血清阳性率低，另一个猪场肉汁中的血清阳性率高。在32个育肥猪场中的6个猪场，共有7.0%（ELISA临界OD%≥40）的屠宰猪血清呈阳性。在16.4%的空肠/淋巴结样本（383只动物）和15.5%的扁桃体样本（129只动物）中发现了沙门氏菌DNA。在41%的血清阳性猪的空肠/淋巴结中发现了沙门氏菌DNA。然而，在空肠DNA检测呈阳性的所有猪中，只有17.5%的猪血清滴度也呈阳性。选择了两个猪场进行进一步调查：13号农场（F13），血清阳性猪的患病率高，为29.0%，属于II类；以及F11农场，患病率为9.4%，属于I类。然而，根据农场检测后育肥猪的血清检测结果进行的分类却大不相同：F13有5%的阳性动物（I类）；而F11有23.3%（II类）。该研究得出了以下结果和建议：第一，ELISA检测对于检测经常受到沙门氏菌污染的农场很有用，但此类检测无法提供屠宰时单个动物（或一组动物）的感染状况信息。第二，采取管理措施以防止通过贸易和运输传播感染至关重要：仔猪应仅由单一知名生产商供应，育肥猪在送去屠宰前应在农场进行血清学检测。第三，ELISA检测和PCR方法适用于沙门氏菌的检测，推荐作为所有猪肉质量控制计划的分析工具。第四，来自可疑农场的动物应始终在屠宰日结束时屠宰，随后进行彻底清洁和消毒。
