| Popis: |
Growth response from spores and vegetative cells of Clostridium botulinum strain 52A in peptone-yeast extract-glucose (PYEG) broth at two pH levels (5.55 or 5.85) containing sodium acid pyrophosphate (SAPP) (0, 0.2, 0.4%), NaCl (0, 1.25, 2.50%) and/or potassium sorbate (KS) (0, 0.13, 0.26%) was measured as the mean A630 nm of 20 tubes at 37°C. Additional treatments contained KC1 and MgCl2 (0, 1.25, 2.50%) without SAPP or KS. Growth ratios (GR = treatment/control) based on time to reach A630 = 0.35 were calculated to compare effects of additives on strain 52A. Growth from spores was affected significantly (p≤0.01) by pH level. KS and KS/pH interactions were also significant factors in growth from both spores and vegetative cells; SAPP/pH interactions were significant for cell growth, only. Combinations of SAPP (0.2, 0.4%) NaCl (0%) and KS (0.26%) were the most favorable treatments for delaying growth from spores or vegetative cells. NaCl (1.25, 2.50%) decreased antibotulinal effects produced by combination... |
