Korkeala H, Stengel G, Hyytiä E, Vogelsang B, Bohl A, Wihlman H, Pakkala P, Hielm S
Department of Food and Environmental Hygiene, University of Helsinki, Finland.
Int J Food Microbiol. 1998 Aug 18;43(1-2):1-5. doi: 10.1016/s0168-1605(98)00080-4.
On January 16, 1997 two Germans got botulism after eating hot-smoked Canadian whitefish produced in Finland. The serum sample of one of the patients contained 6 MLD/ml of botulinum toxin. The type of toxin was identified as E by the toxin neutralization test and the botulinum neurotoxin type E (BoNT/E) gene was also amplified from the serum by polymerase chain reaction (PCR), but C. botulinum could not be isolated from the positive serum sample. The remains of the hot-smoked whitefish eaten by the patients contained botulinum toxin detected by the mouse bioassay and the BoNT/E gene as determined by PCR. C. botulinum was isolated from the fish sample and it was confirmed to be type E by the mouse bioassay and by PCR. Eleven other fish samples from the same lot did not contain botulinum toxin nor any BoNT gene. The incriminated food was processed on the 9th and 10th of January, 1997 from frozen whitefish imported to Finland from Canada. The pulsed-field gel electrophoretic pattern of the isolated C. botulinum strain resembled a reference strain of North American origin. It did not match any C. botulinum strains isolated from the Baltic sea-bottom or from the fish caught in the area indicating that the fish was contaminated by C. botulinum in Canada. The conditions resulting in toxin production could not be identified. The safety problems associated with vacuum-packaged hot-smoked fish seem to be of utmost concern and the product is one of the most important botulism food vehicles processed on an industrial scale. Temperature monitoring and the use of time-temperature indicators are to be recommended in order to ensure adequate storage temperature from processing through to consumption. Allowing the use of nitrate and nitrite together with sufficiently high NaC1 concentration in this particular product should also be considered.
1997年1月16日，两名德国人食用了产自芬兰的热熏加拿大白鱼后感染肉毒中毒。其中一名患者的血清样本含有6 MLD/ml的肉毒杆菌毒素。通过毒素中和试验确定毒素类型为E型，并且还通过聚合酶链反应（PCR）从血清中扩增出了肉毒杆菌神经毒素E型（BoNT/E）基因，但在阳性血清样本中未分离出肉毒梭菌。患者食用的热熏白鱼残骸经小鼠生物测定法检测含有肉毒杆菌毒素，经PCR测定含有BoNT/E基因。从鱼样本中分离出了肉毒梭菌，通过小鼠生物测定法和PCR确认其为E型。同一批次的其他11个鱼样本既不含肉毒杆菌毒素，也不含任何BoNT基因。涉事食品于1997年1月9日和10日由从加拿大进口到芬兰的冷冻白鱼加工而成。分离出的肉毒梭菌菌株的脉冲场凝胶电泳图谱类似于北美来源的参考菌株。它与从波罗的海海底或该地区捕获的鱼类中分离出的任何肉毒梭菌菌株均不匹配，这表明该鱼在加拿大被肉毒梭菌污染。无法确定导致毒素产生的条件。与真空包装热熏鱼相关的安全问题似乎最为令人担忧，该产品是工业规模加工的最重要的肉毒中毒食物载体之一。建议进行温度监测并使用时间 - 温度指示器，以确保从加工到消费的储存温度适宜。还应考虑允许在此特定产品中同时使用硝酸盐和亚硝酸盐以及足够高浓度的氯化钠。
