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首页> 外文期刊>Applied Microbiology >Storage Stability of Clostridium botulinum Toxin and Spores in Processed Cheese
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Storage Stability of Clostridium botulinum Toxin and Spores in Processed Cheese

机译：肉毒梭菌毒素和孢子在加工奶酪中的储存稳定性

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Growth initiated from detoxified spores of Clostridium botulinum 62A resulted in toxin production of 50 to 10,000 mouse lethal doses (MLD) per gram of processed soft surface-ripened cheese. Regular assays during subsequent storage of toxic samples at 2 to 4 C revealed a characteristic two- to fivefold increase in toxin titer during the initial 1 week to 12 months of storage. Thereafter, the toxin titer remained constant for 2 to 4 years, after which the toxicity declined rapidly. At the end of 6 years of storage at 2 to 4 C, the samples still contained 20 to 5,000 MLD of toxin per gram, with the usual toxin level at 200 to 500 MLD. Toxic culture filtrates of C. botulinum incorporated into cheese and stored at 30 C for 60 days showed no decline in toxin in processed type I cheese, but toxin decreased slightly in processed type II and type III cheese. The surface flora of these cheeses did not attack but, on the contrary, protected C. botulinum toxin during storage at 30 C. Initial difficulties in recovering C. botulinum organisms from type I cheese were traced to growth inhibitory activity which could be removed by washing with distilled water in a centrifuge. Viable spores or vegetative cells could be recovered from all samples after 4 to 5 years of storage at 2 to 4 C. After 6 years, organisms were recovered from all except three samples of type I cheese. Two other samples showed a large decrease in viable organisms. In type III cheese, spores remained remarkably stable for 6 years at the level of the initial inoculum, i.e., approximately 105 spores per gram.
机译：由肉毒梭菌62A的解毒孢子引发的生长导致每克加工的软化表面熟化的奶酪产生50至10,000小鼠致死剂量（MLD）的毒素。随后在2至4 C下储存有毒样品期间的常规分析表明，在储存的最初1周至12个月期间，毒素滴度的特征增加了2至5倍。此后，毒素效价在2至4年内保持恒定，此后毒性迅速下降。在2至4 C下保存6年后，样品仍包含每克20至5,000 MLD毒素，通常毒素水平为200至500 MLD。肉毒梭菌的有毒培养滤液并入干酪中，并在30°C下储存60天，显示加工后的I型干酪中毒素没有下降，但是加工后的II型和III型干酪中毒素略有减少。这些干酪的表面菌群没有受到攻击，相反，在30°C的储存过程中保护了肉毒梭菌毒素。从I型干酪中回收肉毒梭菌的最初困难可追溯到生长抑制活性，可以通过洗涤除去用蒸馏水在离心机上。在2至4 C下保存4至5年后，可以从所有样品中回收活的孢子或营养细胞。6年后，可以从除三个I型干酪样品中的所有样品中回收生物。另外两个样本显示有活力的生物大量减少。在III型干酪中，孢子在初始接种物的水平（即每克约105个孢子）下保持了6年的稳定。

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