Laboratory of Food Microbiology, Wageningen University, Wageningen, the Netherlands.
J Appl Microbiol. 2010 Jul;109(1):137-45. doi: 10.1111/j.1365-2672.2009.04637.x. Epub 2009 Nov 28.
Tempe, a Rhizopus ssp.-fermented soya bean food product, was investigated for bacteriostatic and/or bactericidal effects against cells and spores of the food-borne pathogen Bacillus cereus.
Tempe extract showed a high antibacterial activity against B. cereus ATCC 14579 based on optical density and viable count measurements. This growth inhibition was manifested by a 4 log CFU ml(-1) reduction, within the first 15 min of exposure. Tempe extracts also rapidly inactivated B. cereus spores upon germination. Viability and membrane permeability assessments using fluorescence probes showed rapid inactivation and permeabilization of the cytoplasmic membrane confirming the bactericidal mode of action. Cooked beans and Rhizopus grown on different media did not show antibacterial activity, indicating the unique association of the antibacterial activity with tempe. Subsequent characterization of the antibacterial activity revealed that heat treatment and protease addition nullified the bactericidal effect, indicating the proteinaceous nature of the bioactive compound.
During fermentation of soya beans with Rhizopus, compounds are released with extensive antibacterial activity against B. cereus cells and spores.
The results show the potential of producing natural antibacterial compounds that could be used as ingredients in food preservation and pathogen control.
研究根霉发酵大豆食品 Tempe 对食源性致病菌蜡样芽孢杆菌细胞和孢子的抑菌和/或杀菌作用。
根据光密度和活菌计数测量，Tempe 提取物对蜡样芽孢杆菌 ATCC 14579 表现出很高的抗菌活性。在暴露的最初 15 分钟内，这种生长抑制表现为 4 个对数 CFU ml(-1)的减少。Tempe 提取物也能迅速使发芽的蜡样芽孢杆菌孢子失活。使用荧光探针进行的存活和膜通透性评估显示，细胞质膜迅速失活和渗透，证实了杀菌作用模式。煮熟的豆子和在不同培养基上生长的根霉没有表现出抗菌活性，表明这种抗菌活性与 Tempe 有着独特的联系。随后对抗菌活性进行了表征，发现热处理和添加蛋白酶使杀菌作用无效，表明活性化合物是蛋白质性质的。
在大豆与根霉发酵过程中，会释放出具有广泛的抗蜡样芽孢杆菌细胞和孢子活性的化合物。
结果表明，有可能生产出天然抗菌化合物，可作为食品保鲜和病原体控制的成分。
