Universidad CEU Cardenal Herrera, Dpto. Producción y Sanidad Animal, Salud Pública Veterinaria y Ciencia y Tecnología de los Alimentos, C/ Tirant lo Blanc, 7, 46115 Alfara del Patriarca, Valencia, Spain.
Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Dpto. Conservación y Calidad, c/ Catedrático Agustin Escardino, 7, 46980 Paterna, Valencia, Spain.
Int J Food Microbiol. 2017 Jun 5;250:7-11. doi: 10.1016/j.ijfoodmicro.2017.03.006. Epub 2017 Mar 16.
The effect of Stevia rebaudiana Bertoni on the hemolytic potential of Listeria monocytogenes was studied by means of the assessment of the Listeriolysin O (LLO) production. The three factors under study, stevia concentration in the range [0-2.5] % (w/v), incubation temperature (10 and 37°C), and exposure time (0-65h) significantly affected (p≤0.05) the hemolytic activity of L. monocytogenes. Results showed that at the lower incubation temperature the hemolytic potential of the bacterium was significantly reduced, from 100% at 37°C to 8% at 10°C (after 65h of incubation) in unsupplemented substrate (0% stevia). Irrespective of the temperature, 10 or 37°C, supplementation of the medium with stevia at 2.5 % (w/v) reduced the bacterium's hemolytic activity by a maximum of 100%. Furthermore, the time of exposure to 2.5 % (w/v) stevia concentration was also a significant factor reducing the hemolytic capability of L. monocytogenes. The possibility of reducing the pathogenic potential of L. monocytogenes (hemolysis) by exposure to stevia should be confirmed in real food matrices, opening a research niche with a valuable future impact on food safety.
采用溶血素 O (LLO) 产量评估方法，研究甜菊糖 Rebaudiana Bertoni 对单核细胞增生李斯特菌溶血潜能的影响。研究的三个因素，即在[0-2.5]%（w/v）范围内的甜菊糖浓度、孵育温度（10℃和 37℃）和暴露时间（0-65h），显著影响（p≤0.05）单核细胞增生李斯特菌的溶血活性。结果表明，在较低的孵育温度下，细菌的溶血潜能显著降低，在未添加基质（0%甜菊糖）的情况下，从 37℃时的 100%降低至 10℃时的 8%（孵育 65h 后）。无论温度为 10℃还是 37℃，在培养基中添加 2.5%（w/v）的甜菊糖可将细菌的溶血活性最大降低 100%。此外，暴露于 2.5%（w/v）甜菊糖浓度的时间也是降低单核细胞增生李斯特菌溶血能力的重要因素。在实际食品基质中确认甜菊糖降低单核细胞增生李斯特菌（溶血）致病潜力的可能性，将为食品安全带来具有宝贵未来影响的研究领域。
