Comparison and improvement of detection media for sub-lethal injured Clostridium perfringens
2009
Shimizu, S.(Hokkaido Univ., Hakodate (Japan)) | Horiguchi, A. | Yamazaki, K. | Kawai, Y.
Recovery of heat-injured vegetative cells and spores of Clostridium perfringens was evaluated on selective media, CW egg-yolk agar with kanamycin (ECWsup(+)A), tryptose sulfite cycloserine agar (TSCsup(+)A) and modified Handford agar (mHFA). As a result of heat treatment at 54degC for 15 min, viable counts of C. perfringens vegetative cells on a selective medium (ECWsup(+)A) were significantly less than those on non-selective media. This means C. perfringens vegetative cells should be in an injured state. Comparing of the three selective media, TSCsup(+)A was the best growth and recovery of heat-injured C. perfringens vegetative cells. Recovery on ECWsup(+)A was 1 log CFU/ml less than that on TSCsup(+)A. Supplementation of TSCsup(+)A with sodium pyruvate (0.1-0.5%) further enhanced recovery and detection of heat-injured C. perfringens vegetative cells, and its efficacy was the highest on TSCsup(+)A supplemented with 0.3% sodium pyruvate. Supplementation of TSCsup(+)A with sodium pyruvate did not affect recovery of heat-injured (95degC, 2 or 60 min) C. perfringens spores. These findings suggest that TSCsup(+)A is the most favorable medium for enumeration of C. perfringens and supplementation with sodium pyruvate improves recovery and detection of heat-injured C. perfringens.
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