Departamento de Ingeniería de Alimentos y del Equipamiento Agrícola, Instituto de Biotecnología Vegetal, Universidad Politécnica de Cartagena (ETSIA), Paseo Alfonso XIII, 48, 30203 Cartagena, Spain.
Departamento de Ingeniería de Alimentos y del Equipamiento Agrícola, Instituto de Biotecnología Vegetal, Universidad Politécnica de Cartagena (ETSIA), Paseo Alfonso XIII, 48, 30203 Cartagena, Spain.
Food Microbiol. 2018 Jun;72:98-105. doi: 10.1016/j.fm.2017.11.005. Epub 2017 Nov 13.
In this study, growth and/or inactivation of Listeria monocytogenes 4032 at different inoculum levels in a vegetable smoothie with purple colour, (previously heat stabilised at 95 °C for 3 min) was evaluated. Growth/inactivation was compared with acidified TSB medium at the same pH level with HCl. Samples were stored at different temperatures (5, 10, 15 and 25 °C). All the smoothies stored at 15 and 25 °C showed growth up to 7.5-8.0 log CFU/mL and at 10 °C growth was only observed at the highest inoculum level. Growth was only observed at 25 °C in acidified TSB. In the case of the smoothies inoculated and stored at 5 °C, L. monocytogenes was not able to grow but survived for a long period of time, whereas at the lower inocula at 10 °C they presented a slow inactivation for an extended time. Acidified TSB inoculated and stored showed inactivation at 5, 10 and 15 °C. Best inactivation modelling alternatives are proposed. The differences between the smoothie and TSB medium about growth or survival in this study, even at relatively low pH values, were due to the favorable nutritional composition of the smoothie compared to a laboratory medium. Results in this study can allow to design safe conditions for smoothie production.
本研究评估了不同接种水平的产单核李斯特菌 4032 在具有紫色的蔬菜冰沙（先前经 95°C 热稳定化 3 分钟）中的生长和/或失活情况。使用 HCl 将酸化解育肉汤 (TSB) 培养基的 pH 值调节至与冰沙相同的水平，并将其与冰沙的生长/失活情况进行比较。将样品储存在不同温度（5、10、15 和 25°C）下。所有在 15 和 25°C 下储存的冰沙均显示出高达 7.5-8.0 log CFU/mL 的生长，而在 10°C 下仅在最高接种水平下观察到生长。仅在 25°C 下的酸化 TSB 中观察到生长。在接种并储存在 5°C 的冰沙中，产单核李斯特菌无法生长，但能存活很长时间，而在较低接种量的 10°C 下，它们在较长时间内呈现缓慢失活。接种并储存在酸化 TSB 中的细菌在 5、10 和 15°C 下失活。提出了最佳失活模型替代方案。即使在相对较低的 pH 值下，冰沙和 TSB 培养基之间在生长或存活方面的差异是由于冰沙与实验室培养基相比具有更有利的营养成分。本研究的结果可以为冰沙生产设计安全条件。
