Harmon S M, Placencia A M
J Assoc Off Anal Chem. 1978 Jul;61(4):785-8.
A collaborative study was conducted in 12 laboratories to determine the effectiveness of a new method for maintaining vegetative cells of Clostridium perfringens in viable condition during storage and transport of food specimens to the laboratory. The collaborative results showed that treatment of brown gravy and roast beef samples with an equal amount by weight of sterile buffered glycerol-sodium chloride solution to give a final 10% glycerol concentration and storage with Dry Ice for 10 days at -56 degrees C resulted in plate counts of C. perfringens which were 2-4 log cycles higher with 2 different strains than counts with untreated specimens stored by the usual method at -20 degrees C. Plate counts obtained with the treated specimens stored with Dry Ice were less than 1 log cycle lower than counts made with identical specimens before freezing for storage and shipment to the collaborators. The results with treated specimens were also more uniform among the different laboratories. Because the new method for storage and shipment of food samples was so effective for maintaining viability of the organism, the official first action method for C. perfringens (46.B01) was changed to incorporate these procedures as part of the method.
在12个实验室开展了一项合作研究，以确定一种新方法在将食品标本储存和运输至实验室期间维持产气荚膜梭菌营养细胞存活状态的有效性。合作研究结果表明，用等量重量的无菌缓冲甘油 - 氯化钠溶液处理棕色肉汁和烤牛肉样品，使最终甘油浓度达到10%，并在 -56℃ 用干冰储存10天，对于两种不同菌株，产气荚膜梭菌的平板计数比采用常规方法在 -20℃ 储存的未处理标本的计数高2 - 4个对数周期。用干冰储存的处理后标本获得的平板计数比冷冻前用于储存并运送至合作实验室的相同标本的计数低不到1个对数周期。处理后标本在不同实验室的结果也更一致。由于食品样品储存和运输的新方法在维持该微生物的活力方面非常有效，产气荚膜梭菌的官方首次行动方法（46.B01）进行了更改，将这些程序纳入该方法的一部分。
