Department of Food Science and Human Nutrition, Iowa State University, 2312 Food Science Building, Ames, Iowa 50011, USA.
J Food Prot. 2010 Feb;73(2):266-73. doi: 10.4315/0362-028x-73.2.266.
Grape seed extract (GSE) is a rich source of proanthocyanidins, a class of natural antioxidants reported to have wide-ranging bioactivity as anti-inflammatory, anticarcinogenic, and antimicrobial agents. The ability of GSE to rapidly inactivate Listeria monocytogenes in vitro and the generally recognized as safe status of GSE make this extract an attractive candidate for control of Listeria in or on foods. Previously, GSE has been used at relatively high concentrations (1%) in complex food matrices and in combination with other antimicrobials. We sought to characterize the antilisterial effects of a commercial GSE preparation (Gravinol-S) alone at much lower concentrations (0.00015 to 0.125%) in aqueous solution and to test its possible use as an antimicrobial wash for fresh produce surfaces. Based on broth microdilution tests, the MICs of GSE against L. monocytogenes Scott A and Listeria innocua ATCC 33090 were as low as 50 and 78 mug ml(-1), respectively. GSE was evaluated in 0.85% saline against live cells of L. innocua via flow cytometry, using propidium iodide as a probe for membrane integrity. At sub-MICs and after only 2 min of exposure, treatment with GSE caused rapid permeabilization and clumping of L. innocua, results that we confirmed for L. monocytogenes using fluorescence microscopy and Live/Dead staining. At higher concentrations (0.125%), GSE reduced viable cell counts for L. monocytogenes by approximately 2 log units within 2 min on tomato surfaces. These results suggest the potential for GSE as a natural control of Listeria spp. on low-complexity foods such as tomatoes.
葡萄籽提取物（GSE）是原花青素的丰富来源，原花青素是一类具有广泛生物活性的天然抗氧化剂，具有抗炎、抗癌和抗菌作用。GSE 能够在体外迅速使李斯特菌失活，并且 GSE 的一般公认安全状态使其成为控制食品中或食品表面李斯特菌的有吸引力的候选物。此前，GSE 已在复杂的食品基质中以相对较高的浓度（1%）使用，并与其他抗菌剂联合使用。我们试图在水溶液中以低得多的浓度（0.00015 至 0.125%）单独表征一种商业 GSE 制剂（Gravinol-S）的抗李斯特菌作用，并测试其作为新鲜农产品表面抗菌洗涤液的可能用途。基于肉汤微量稀释试验，GSE 对李斯特菌斯科特 A 和无害李斯特菌 ATCC 33090 的 MIC 低至 50 和 78 mug ml（-1）。通过流式细胞术，使用碘化丙啶作为膜完整性的探针，在 0.85%盐水中评估 GSE 对活细胞的李斯特菌 innocua 的作用。在亚 MIC 浓度下，并且仅暴露 2 分钟后，用 GSE 处理会导致无害李斯特菌迅速渗透和聚集，我们使用荧光显微镜和 Live/Dead 染色证实了李斯特菌 monocytogenes 的结果。在较高浓度（0.125%）下，GSE 在番茄表面 2 分钟内使李斯特菌 monocytogenes 的活菌数减少了约 2 个对数单位。这些结果表明 GSE 有潜力作为天然控制物来控制低复杂度食品中的李斯特菌属。
