UMR408 SQPOV « Sécurité et Qualité des Produits d'Origine Végétale », INRA, University of Avignon, 84000 Avignon, France.
UMR408 SQPOV « Sécurité et Qualité des Produits d'Origine Végétale », INRA, University of Avignon, 84000 Avignon, France.
Food Microbiol. 2016 Oct;59:119-23. doi: 10.1016/j.fm.2016.05.015. Epub 2016 May 30.
Psychrotrophic strains of the foodborne pathogen Bacillus cereus can multiply during the refrigerated storage of food products. The aim of this study was to determine the impact of anaerobiosis on the growth of two psychrotrophic B. cereus strains exposed to acidic pH at a cold temperature in a laboratory medium. At 10 °C, growth occurred at pH values equal to or higher than 5.7 during anaerobiosis, whereas aerobic growth was observed from pH 5.4. Growth rates during aerobiosis were similar at pH 5.4 and pH 7. No growth was observed for the two tested strains at 8 °C without oxygen regardless of the pH; however, both strains grew at this temperature from pH 5.4 in the presence of oxygen. These pH growth limits in aerobiosis are consistent with those reported for different strains and different foods or media, but no other studies have described anaerobic growth at acidic pH values. The maximal B. cereus concentration was approximately 6.0 log10 CFU/ml for cultures in the absence of oxygen and approximately 8.0 log10 CFU/ml for cultures in the presence of oxygen. In conclusion, we found that the combination of anaerobiosis, pH < 5.7 at 10 °C, or anaerobiosis and temperatures ≤8 °C prevent psychrotrophic B. cereus growth.
食源性致病菌蜡样芽孢杆菌的低温菌株可以在冷藏储存食品的过程中繁殖。本研究旨在确定在低温下酸性 pH 值和无氧环境对两种低温蜡样芽孢杆菌菌株生长的影响。在 10°C 时，无氧条件下 pH 值等于或高于 5.7 时会发生生长，而有氧条件下则从 pH 5.4 开始观察到生长。在 pH 5.4 和 pH 7 下，有氧条件下的生长速率相似。无论 pH 值如何，两种受试菌株在 8°C 时无氧都不会生长；然而，在有氧条件下，两种菌株都可以从 pH 5.4 开始在该温度下生长。这些有氧条件下的 pH 生长限制与不同菌株和不同食品或培养基报告的结果一致，但没有其他研究描述过酸性 pH 值下的无氧生长。在无氧和有氧条件下，细菌的最大浓度分别约为 6.0 log10 CFU/ml 和 8.0 log10 CFU/ml。总之，我们发现无氧、10°C 时 pH<5.7 或无氧和温度≤8°C 的组合可以防止低温蜡样芽孢杆菌的生长。
