Data_Sheet_1_Assessment of the Distribution and Safety of Tetragenococcus muriaticus for Potential Application in the Preparation of Chinese Grasshopper Sub Shrimp Paste.doc

The bacterial profiles of 63 grasshopper sub shrimp paste samples collected from seven typical regions around the Bohai Sea were investigated by high-throughput sequencing. Tetragenococcus muriaticus was found to be the prevailing species present in all the samples, and the presence of T. muriaticus also weakly correlated with the histamine content in the samples. Six T. muriaticus strains with low biogenic amine (BA)-producing ability and deficient in histamine production were identified and subjected to safety assessment. All six strains displayed weak resistance to fifteen known antibiotics as based on the Enterococcus breakpoint values. None of the strains exhibited hemolytic activity or biofilm formation. All strains exhibited were able to grow on MRS agar containing 21% NaCl and expressed amine oxidase and strain-specific proteases and lipases. Most of the strains exhibited acid production at 18% NaCl. Moreover, three of the strains (designated as SG, TS, and QH) with histamine degradation ability were inoculated into separate shrimp paste samples to determine their effect on BA accumulation. The results indicated that the addition of T. muriaticus to shrimp pastes not only led to a significant reduction of BA content in the pastes but also improved the flavor of the pastes. Consequently, these strains may be used as potential candidates for controlling the content of histamine in fermented foods.

本研究采用高通量测序技术，对环渤海7个典型区域采集的63份草虾酱样品的细菌群落谱进行了分析。结果显示，嗜盐四联球菌（Tetragenococcus muriaticus）为所有样品中的优势菌种，且其相对丰度与样品中的组胺含量呈弱相关。本研究筛选得到6株产生物胺（biogenic amine, BA）能力较弱且不产组胺的嗜盐四联球菌菌株，并对其开展安全性评价：基于肠球菌属药敏折点标准，6株菌株均对15种常用抗生素表现出较弱的耐药性；所有菌株均未表现出溶血活性与生物膜形成能力；均可在含21%氯化钠的MRS琼脂平板上生长，并可表达胺氧化酶、菌株特异性蛋白酶及脂肪酶；多数菌株可在18%氯化钠环境中产酸。此外，选取3株具备组胺降解能力的菌株（命名为SG、TS与QH），分别接种至单独的草虾酱样品中以探究其对生物胺积累的影响。实验结果表明，向草虾酱中添加该嗜盐四联球菌菌株，不仅可显著降低样品中的生物胺含量，还可改善虾酱的风味品质。综上，该类菌株可作为调控发酵食品中组胺含量的潜在候选菌株。