Department of Food Science, Institute for Postharvest and Food Sciences, The Volcani Center, Agriculture Research Organization, Rishon-LeZion, Israel; College of Veterinary Medicine, Western University of Health Sciences, Pomona, CA, 91766, USA.
Department of Food Science, Institute for Postharvest and Food Sciences, The Volcani Center, Agriculture Research Organization, Rishon-LeZion, Israel.
Food Microbiol. 2019 Dec;84:103261. doi: 10.1016/j.fm.2019.103261. Epub 2019 Jul 6.
Sprouts are considered a healthy ready-to-eat food and has gained popularity in recent years. The objective of the present study was to determine the dynamics of sprouts' microbiome during cold storage to the end of their shelf-life at home. The microbiological quality of fresh alfalfa (Medicago sativa) and mung bean (Vigna radiata) sprouts from two commercial brands was tested and the number of APC ranges from 5.0 to 8.7 log CFU/g in alfalfa and 6.7 to 9.3 log CFU/g in mung bean sprouts. In the case of alfalfa, but not mung beans, there were differences in the mean numbers of APC between the two brands. The number of coliform bacteria ranges from 4.3 to 7.7 log CFU/g in alfalfa and 4.1 to 8.1 log CFU/g in mung bean sprouts. Four independent batches of sprouts were used for DNA preparation and were sampled immediately after purchase and once a week during subsequent storage in refrigerator until the end of their shelf-life. Microbial population of the sprouts was determined using next generation sequencing of 16S rRNA amplicons. Alfalfa sprouts were dominated by Pseudomonas throughout the storage time with relative abundance of >60% at 3 weeks. Fresh mung bean sprouts were dominated by both Pseudomonas and Pantoea, but Pantoea became the dominant taxa after 2 weeks of storage, with >46% of relative abundance. The bacterial communities associated with sprouts were largely dependent on the sprout type, and less dependent on the brand. The species richness and diversity declined during storage and the development of spoilage. Among the 160 genera identified on sprouts, 23 were reported to contain known spoilage-associated species and 30 genera comprise potential human pathogenic species. This study provides new insight into the microbiome dynamics of alfalfa and mung bean sprouts during cold storage.
芽苗菜被认为是一种健康的即食食品，近年来越来越受欢迎。本研究的目的是确定芽苗菜在冷藏过程中的微生物组动态，直至其在家中的货架期结束。测试了来自两个商业品牌的新鲜紫花苜蓿（Medicago sativa）和绿豆（Vigna radiata）芽苗菜的微生物质量，紫花苜蓿芽苗菜中 APC 的数量范围为 5.0 至 8.7 log CFU/g，绿豆芽苗菜中 APC 的数量范围为 6.7 至 9.3 log CFU/g。在紫花苜蓿中，但不在绿豆中，两个品牌之间 APC 的平均数量存在差异。大肠菌群的数量范围为 4.3 至 7.7 log CFU/g的紫花苜蓿和 4.1 至 8.1 log CFU/g的绿豆芽苗菜。四个独立批次的芽苗菜用于 DNA 制备，并在购买后立即采样，随后在冰箱中储存期间每周采样一次，直到货架期结束。使用 16S rRNA 扩增子的下一代测序来确定芽苗菜的微生物种群。在整个贮藏期间，紫花苜蓿芽苗菜一直以假单胞菌为主，3 周时相对丰度>60%。新鲜绿豆芽苗菜最初以假单胞菌和泛菌为主，但在贮藏 2 周后，泛菌成为优势菌群，相对丰度>46%。与芽苗菜相关的细菌群落主要取决于芽苗菜的类型，而与品牌的关系较小。在贮藏过程中，物种丰富度和多样性下降，同时出现腐败现象。在所鉴定的 160 个芽苗菜属中，有 23 个被报道含有已知的腐败相关物种，30 个属包含潜在的人类病原性物种。本研究为紫花苜蓿和绿豆芽苗菜在冷藏过程中的微生物组动态提供了新的见解。
