Ghoddusi Hamid B, Sherburn Richard E, Aboaba Olusimbo O
Microbiology Research Unit, School of Human Sciences, London Metropolitan University, London N7 8DB, UK.
ISRN Microbiol. 2013 Sep 30;2013:731430. doi: 10.1155/2013/731430. eCollection 2013.
Some rare strains of Clostridium butyricum carry the gene encoding the botulinal type E neurotoxin and must be considered as possible hazards in certain types of food. The limiting growth conditions for C. butyricum were determined in peptone yeast glucose starch (PYGS) broth incubated anaerobically at 30°C for up to 42 days. The minimum pH values permitting growth depended on the acidulant and strain. Organic acids were more effective at inhibiting growth than HCl as expected. The lowest pH values at which growth of toxigenic and nontoxigenic strains of C. butyricum was observed in broth acidified with HCl were 4.1 and 4.2, respectively. In organic acids, however, the minimum pH varied between 4.4 and 5.1 depending on acid type and concentration. The minimum water activity for growth of toxigenic strains of C. butyricum was 0.96. The minimum growth temperatures of the toxigenic strains of C. butyricum (ca 10-11°C) were somewhat higher than for non-toxigenic ones (8°C). It was concluded that control of toxigenic C. butyricum in the food industry needs to allow for the greater pH tolerance of this species compared with proteolytic C. botulinum.
一些罕见的丁酸梭菌菌株携带编码E型肉毒杆菌神经毒素的基因,在某些类型的食品中必须被视为潜在危害。在30°C厌氧培养长达42天的蛋白胨酵母葡萄糖淀粉(PYGS)肉汤中确定了丁酸梭菌的生长限制条件。允许生长的最低pH值取决于酸化剂和菌株。正如预期的那样,有机酸在抑制生长方面比盐酸更有效。在用盐酸酸化的肉汤中观察到产毒和不产毒的丁酸梭菌菌株生长的最低pH值分别为4.1和4.2。然而,在有机酸中,最低pH值根据酸的类型和浓度在4.4至5.1之间变化。产毒丁酸梭菌菌株生长的最低水分活度为0.96。产毒丁酸梭菌菌株的最低生长温度(约10 - 11°C)略高于不产毒菌株(8°C)。得出的结论是,与蛋白水解型肉毒杆菌相比,食品工业中控制产毒丁酸梭菌需要考虑该菌种对pH值更高的耐受性。