Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G2W1, Canada.
Int J Food Microbiol. 2010 Jan 1;136(3):340-4. doi: 10.1016/j.ijfoodmicro.2009.10.026. Epub 2009 Oct 30.
Blood, liver, kidney, lymph nodes and muscle tissue were obtained from the carcasses of five cows with advanced Johne's disease. Samples from the raw tissues, from cooked muscle tissues and from cooked hamburger patties that contained chopped mesenteric lymph nodes were collected aseptically. Each sample was divided into two portions, one of which was decontaminated. Both portions were homogenized. Homogenates were spread on selective agar for the recovery of Mycobacterium avium subsp. paratuberculosis (Map) and inoculated into a Map growth medium with the organism being detected in the cultures by PCR procedures and Ziehl-Neelsen staining. Map were recovered at numbers > 10(3) cfu/g from 7 of 15 liver and mesenteric and ileocaecal lymph node samples; and at lesser numbers from 5 of 15 kidney and superficial inguinal and prescapular lymph node samples. The numbers recovered from decontaminated and not decontaminated portions of each sample were generally similar. Map was recovered from 1 and detected in 6 of 50 not decontaminated portions of samples of raw, chilled or frozen meat; and detected in 1 of 15 not decontaminated samples of meat cooked to 61 degrees C, and in 1 of 40 samples of meat cooked to >/=70 degrees C. Map was detected in 2 of 4 samples of mesenteric lymph nodes cooked to 61 degrees C, but not in samples cooked to > or =70 degrees C. The findings indicate that Map may be present in meat from infected animals at low numbers, but that any such organisms are likely to be inactivated when meat is cooked to a well done condition.
从患有晚期约翰氏病的五头奶牛的尸体中获得了血液、肝脏、肾脏、淋巴结和肌肉组织。无菌采集了生组织、熟肌肉组织和含有切碎肠系膜淋巴结的熟汉堡肉饼的样本。每个样本分为两部分，一部分进行消毒。两部分均进行匀浆。将匀浆涂在选择性琼脂上，以回收禽分枝杆菌副结核亚种（Map），并将其接种到 Map 生长培养基中，通过 PCR 程序和齐尔-尼尔森染色检测培养物中的细菌。从 15 个肝、肠系膜和回盲淋巴结样本中，有 7 个样本的 Map 回收数量超过 10（3）cfu/g；从 15 个肾和浅表腹股沟和肩胛前淋巴结样本中，有 5 个样本的 Map 回收数量较少。从每个样本的消毒和未消毒部分回收的数量通常相似。从 50 个未经消毒的生、冷藏或冷冻肉样本中，有 1 个和 6 个样本的未消毒部分中回收并检测到 Map；从 15 个加热至 61°C 的未消毒肉样本中检测到 1 个，从 40 个加热至 >/=70°C 的肉样本中检测到 1 个。从加热至 61°C 的 4 个肠系膜淋巴结样本中检测到 2 个，但从加热至 >或 =70°C 的样本中未检测到。这些发现表明，Map 可能存在于受感染动物的肉中数量较少，但当肉煮熟至熟透状态时，任何此类细菌都可能被灭活。
