Study of bacterial and fungal community structures in traditional koumiss from Inner Mongolia

Koumiss is notable for its nutritional functions, and microorganisms in koumiss determine its versatility. In this study, the bacterial and fungal community structures in traditional koumiss from Inner Mongolia, China, were investigated. Our results demonstrated that 6 bacterial phyla represented by 126 genera and 49 species and 3 fungal phyla represented by 59 genera and 57 species were detected in 11 samples of artisanal koumiss. Among them, Lactobacillus was the predominant genus of bacterium, and Kluyveromyces and Saccharomyces dominated at the fungal genus level. In addition, there were no differences in the bacterial and fungal richness and diversity of koumiss from 3 neighboring administrative divisions in Inner Mongolia, and the bacterial and fungal community structures (the varieties and relative abundance of bacterial and fungal genera and species) were clearly distinct in individual samples. This study provides a comprehensive understanding of the bacterial and fungal population profiles and the predominant genus and species, which would be beneficial for screening, isolation, and culture of potential probiotics to simulate traditional fermentation of koumiss for industrial and standardized production in the future.     

The effect of ultrasound treatment on microbial and physicochemical properties of Iranian ultrafiltered feta-type cheese

Pasteurization failures in the dairy industry have been reported in many previous studies. Hence, ultrasound, as a nonthermal alternative to pasteurization, has been studied in recent years. In this research, retentate of ultrafiltered milk was pasteurized, inoculated with Escherichia coli O157:H7, Staphylococcus aureus, Penicillium chrysogenum, or Clostridium sporogenes, and then treated with ultrasound for 20 min at frequencies of 20, 40, and 60 kHz and intensity of 80%. Microbial and physicochemical properties of the subsequently produced ultrafiltered white cheeses were investigated throughout 60 d of ripening. Sonication at 20, 40, and 60 kHz reduced counts of E. coli O157:H7, S. aureus, P. chrysogenum, and Cl. sporogenes by 4.08, 4.17, and 4.28 log; 1.10, 1.03, and 1.95 log; 1.11, 1.07, and 1.11 log; and 2.11, 2.03, and 2.17 log, respectively. Sonication improved the acidity of ripened cheese, and sonicated samples had lower pH values than control samples at the end of storage. Sonication did not affect fat in dry matter or the protein content of cheese during ripening, but it did accelerate lipolysis and proteolysis; the highest rates of lipolysis index (free fatty acid content) and proteolysis index (water-soluble nitrogen) were observed on d 60 of ripening for samples sonicated at 60 kHz. Sonication did not affect cohesiveness or springiness of cheese samples, but hardness and gumminess increased in the first 30 d and then decreased until 60 d of storage. Furthermore, ultrasound treatment improved organoleptic properties of the cheese. In terms of overall acceptance, samples sonicated at 60 kHz received the highest sensorial scores. Results showed that sonication can improve microbial, physicochemical, and sensorial properties of ultrafiltered white cheese.     

Fate of Escherichia coli O157:H7 and bacterial diversity in corn silage contaminated with the pathogen and treated with chemical or microbial additives

Inhibiting the growth of Escherichia coli O157:H7 (EC) in feeds may prevent the transmission or cycling of the pathogen on farms. The first objective of this study was to examine if addition of propionic acid or microbial inoculants would inhibit the growth of EC during ensiling, at silo opening, or after aerobic exposure. The second objective was to examine how additives affected the bacterial community composition in corn silage. Corn forage was harvested at approximately 35% dry matter, chopped to a theoretical length of cut of 10 mm, and ensiled after treatment with one of the following: (1) distilled water (control); (2) 1 × 10⁵ cfu/g of EC (ECCH); (3) EC and 1 × 10⁶ cfu/g of Lactobacillus plantarum (ECLP); (4) EC and 1 × 10⁶ cfu/g of Lactobacillus buchneri (ECLB); and (5) EC and 2.2 g/kg (fresh weight basis) of propionic acid, containing 99.5% of the acid (ECA). Each treatment was ensiled in quadruplicate in laboratory silos for 0, 3, 7, and 120 d and analyzed for EC, pH, and organic acids. Samples from d 0 and 120 were also analyzed for chemical composition. Furthermore, samples from d 120 were analyzed for ammonia N, yeasts and molds, lactic acid bacteria, bacterial community composition, and aerobic stability. The pH of silages from all treatments decreased below 4 within 3 d of ensiling. Escherichia coli O157:H7 counts were below the detection limit in all silages after 7 d of ensiling. Treatment with L. buchneri and propionic acid resulted in fewer yeasts and greater aerobic stability compared with control, ECCH, and ECLP silages. Compared with the control, the diversity analysis revealed a less diverse bacterial community in the ECLP silage and greater abundance of Lactobacillus in the ECLP and ECA silages. The ECLB silage also contained greater abundance of Acinetobacter and Weissella than other silages. Subsamples of silages were reinoculated with 5 × 10⁵ cfu/g of EC either immediately after silo opening or after 168 h of aerobic exposure, and EC were enumerated after 6 or 24 h, respectively. All silages reinoculated with EC immediately after silo opening (120 h) had similar low pH values (<4.0) and EC counts were below the detection limit. The ECCH and ECLP silages reinoculated with EC after 168 h of aerobic exposure had relatively high pH values (>5.0) and EC counts (5.39 and 5.30 log cfu/g, respectively) 24 h later. However, those treated with L. buchneri or propionic acid had lower pH values (4.24 or 3.96, respectively) and lower EC counts (1.32 log cfu/g or none, respectively). During ensiling, EC was eliminated from all silages at pH below 4.0. During aerobic exposure, the growth of EC was reduced or prevented in silages that had been treated with L. buchneri or propionic acid at ensiling, respectively.     

内蒙古鄂尔多斯地区酸粥真菌多样性研究

以内蒙古鄂尔多斯地区的3种酸粥为研究对象,采用Illumina Miseq高通量测序技术与传统微生物学手段相结合的方法对其真菌多样性进行研究。结果表明,3种酸粥样品中存在着大量共有真菌菌群,其优势真菌主要由隶属于子囊菌门（Ascomycota）的假丝酵母属（Candida）和耐碱酵母属（Galactomyces）以及隶属于担子菌门（Basidiomycota）的毛孢子菌属（Trichosporon）构成,三者平均相对含量分别为84.30%、11.86%和3.45%;同时从3种酸粥样品中共分离出9株酵母菌,经分子生物学鉴定为茶叶籽酵母（Meyerozyma caribbica）、索拉尼假丝酵母（Candida solani）、库德毕赤酵母（Pichia kudriavzevii）、白地霉（Galactomyces candidum）、解脂耶氏酵母（Yarrowia lipolytica）和隐球酵母（Cryptococcus albidus）各1株以及近平滑假丝酵母（Candida parapsilosis）2株。     

The nutrient requirements of Lactobacillus rhamnosus GG and their application to fermented milk

Lactobacillus rhamnosus GG (LGG) performs many physiological functions, but the fermentation time is long when fermented milk is prepared using LGG alone. To shorten the fermentation time, we analyzed the nutrient requirement profiles of LGG. Based on nutrient requirement profiles, we evaluated the effects on the fermentation time, quality, and sensory properties of unmodified cow's milk fermented by LGG alone. According to the consumption and necessary patterns of amino acids and those of purine, pyrimidine, vitamins, metal ions, and nutrients essential to LGG, we selected Cys, Ser, Arg, Pro, Asp, Glu, guanine, uracil, and xanthine with which to supplement milk. Compared with fermented milk prepared using LGG alone in unmodified milk, the fermentation time of supplemented milk was shortened by 5 h. Viable cell counts, titratable acidity, and water-retaining capability of the fermented milk were improved by addition of nutrient supplements. Supplementation with nutrients did not obviously change the sensory and textural characteristics of fermented milk.     

江苏省徐州市市售发酵与非发酵豆制品微生物污染调查

目的 调查江苏省徐州市市售豆制品微生物污染情况。方法 采集发酵、非发酵豆制品86份, 按照GB 4789进行大肠菌群、菌落总数(非发酵豆制品)、蜡样芽胞杆菌、金黄色葡萄球菌的定量和单核细胞增生李斯特氏菌、沙门氏菌的定性检测。结果 大肠菌群检出率为34.88%, 蜡样芽胞杆菌为12.79%, 金黄色葡萄球菌为1.16%, 其余致病菌均未检出。非发酵豆制品中大肠菌群检出率为65.91%, 计数>103 CFU/g占52.27%, 散装较预包装样品检出率高, 差异有显著意义(P<0.05); 菌落总数>105 CFU/g占75.00%; 蜡样芽胞杆菌检出率为6.82%, 104 CFU/g(均<105 CFU/g)占4.55%; 金黄色葡萄球菌检出率为2.27%。发酵类豆制品中大肠菌群检出率为2.38%, 蜡样芽胞杆菌为19.05%, 104 CFU/g占7.14%(均<105 CFU/g); 预包装、散装样品蜡样芽胞杆菌检出率差异无显著意义(P>0.05)。发酵、非发酵豆制品中大肠菌群检出率差异均有显著意义(P<0.05); 发酵豆制品合格率为97.62%, 非发酵豆制品合格率为11.36%, 差异有显著意义(P<0.05)。结论 徐州市豆制品中非发酵类卫生指标菌污染较为严重, 应加强卫生监督。     

内蒙古科尔沁地区食疗用酸马奶发酵引子化学成分及细菌多样性分析

对内蒙古科尔沁地区食疗用酸马奶发酵引子部分化学指标,包括pH值、糖类、有机酸、游离脂肪酸等进行分析,同时为调查其中细菌多样性,应用Illumina MiSeq第2代测序技术测定其细菌的16S rDNA V3-V4高变区序列,分析物种的丰度、物种分布和Alpha多样性。结果：该酸马奶引子样品pH值为3.54,乳糖、半乳糖质量分数分别为（0.281±0.011）%和（0.100±0.003）%,未检测到葡萄糖;乳酸质量分数为（1.506±0.069）%,丙酸质量分数为（0.053±0.002）%,乙酸质量分数为（0.345±0.014）%,丁酸质量分数为（1.143±0.061）%;共检测到19 种脂肪酸,包括12 种饱和脂肪酸和7 种不饱和脂肪酸;不饱和脂肪酸中α-亚麻酸质量浓度最高,为（14.12±0.36）mg/L;细菌多样性检测结果表明,该样品所获优化序列为（62 082.7±4 868.8）条,可操作分类单元（operational taxonomic units,OTU）数为34.3±2.3;稀释曲线表明该测序深度充分,OTU数接近于饱和。该酸马奶引子细菌主要分布于以下4 个属：乳杆菌属（Lactobacillus）84.08%、醋杆菌属（Acetobacter）9.83%、乳球菌属（Lactococcus）2.41%、链球菌属（Streptococcus）2.18%;其优势菌属为乳杆菌属。以上结果表明,该酸马奶引子不饱和脂肪酸含量丰富,益生菌占主要地位,食品安全有保障。     

酱香型白酒二轮次堆积酒醅微生物群落与理化指标相关性研究

采用高通量测序技术分析酱香型白酒二轮次堆积发酵过程中堆积酒醅微生物群落结构及演替规律。结果表明,酱香型白酒二轮次堆积发酵酒醅中共检测出171个属微生物,其中细菌125个属,真菌46个属。堆积酒醅中优势真菌包括曲霉属（Aspergillus）、假丝酵母属（Candida）、裸胞壳属（Emericella）、毕赤酵母属（Pichia）、红曲霉属（Monascus）、毛孢子菌属（Trichosporon）、节担菌属（Wallemia）、威克汉姆酵母属（Wickerhamomyces）;优势细菌包括芽孢杆菌属（Bacillus）、乳杆菌属（Lactobacillus）、海洋芽孢杆菌属（Oceanobacillus）、高温放线菌属（Thermoactinomyces）、枝芽孢菌属（Virgibacillus）、片球菌属（Pediococcus）、光冈菌属（Mitsuokella）等。相关性分析结果表明,淀粉、总酸含量与曲霉属、裸胞壳属等微生物的丰度呈极显著正相关（P＜0.01）,有利于微生物的生长繁殖;温度、粗蛋白和还原糖的含量与裸胞壳属的丰度呈极显著负相关（P＜0.01）,对裸胞壳属的生长有抑制作用;水分含量与微生物多样性之间的相关性不显著（P≥0.05）。     

Effects of Saccharomyces cerevisiae-based direct-fed microbial and exogenous enzyme products on enteric methane emission and productivity in lactating dairy cows

The objective of this experiment was to investigate the effects of a Saccharomyces cerevisiae-based direct-fed microbial product (SDM) and an exogenous enzyme product (ENZ) on enteric methane emission, milk yield and composition, total-tract digestibility of nutrients, ruminal fermentation, and nitrogen excretion and secretion in lactating dairy cows. Eighteen Holstein cows were used in a 3 × 3 Latin square design experiment with three 28-d periods. Treatments were (1) control (no additive), (2) 28 g of SDM/d per cow, or (3) 10 g of ENZ/d per cow. Treatments were top-dressed at the time of feeding. The basal diet consisted of (dry matter basis) 60% forage and 40% concentrates and contained 16.5% crude protein and 32.0% neutral detergent fiber. Treatments had no effect on enteric methane production, yield (methane per kg of dry matter intake, DMI), or intensity (methane per kg of energy-corrected milk yield). Carbon dioxide production was similar among treatments. Compared with control, SDM increased milk yield by 2 kg/d without affecting DMI or feed efficiency. Supplementation of the diet with ENZ did not affect DMI, milk yield, or feed efficiency. Concentrations and yields of milk fat, true protein, and lactose, and energy-corrected milk yield were not different among treatments. Neither SDM nor ENZ had an effect on total-tract digestibility of nutrients or nitrogen excretion and secretion. Concentration of total volatile fatty acids (VFA) in ruminal fluid was increased by both SDM and ENZ, and rumen pH was decreased by SDM compared with the control. At levels similar to the control DMI, the increased concentration of VFA in ruminal fluid of cows receiving SDM suggests an increased postruminal supply of energy and may partly explain the increased milk yield with that treatment. However, it is important to note that milk composition and energy-corrected milk yield were not affected by treatment.     

内蒙古传统发酵乳制品中乳酸菌的分离及其耐药性研究

以内蒙古通辽地区自制的奶豆腐和酸性奶油（乌日莫）为材料,采用稀释涂布法从中分离乳酸菌,通过分子生物学技术对其进行菌种鉴定,并对其耐药性进行研究。结果表明,共分离纯化得到80株乳酸菌,经鉴定,归属于13个种,分别为短乳杆菌（Lactobacillus brevis）、粪肠球菌（Enterococcus faecalis）、乳酸片球菌（Lactobacillus acidilacticii）、乳酸乳球菌（Lactococcus lactis）、瑞士乳杆菌（Lactobacillus helveticus）、屎肠球菌（Enterococcus faecium）、戊糖片球菌（Pediococcus pentosaceus）、副干酪乳杆菌（Lactobacillus paracasei）、食二酸乳杆菌（Lactobacillus digitalis）、奥塔基乳杆菌（Lactobacillus ottaki）、耐久肠球菌（Enterococcus durans）、植物乳杆菌（Lactobacillus plantarum）、开菲尔乳杆菌（Lactobacillus kefir）,表现出高的生物多样性。80株乳酸菌对萘啶酸的耐药率为100%;对链霉素、环丙沙星、万古霉素的耐药率较高,分别为95.00%、80.00%、72.50%;对利福平和四环素的耐药率中等,分别为51.25%,45.00%;对红霉素、氯霉素的耐药率较低,分别为26.25%、23.75%。此外,76株（95%）的乳酸菌还具有多重耐药性。     

The chemical composition of human milk from Inner Mongolia of China

In Inner Mongolia, China, the chemical composition of 66 breast milk samples at three lactation stages was analysed. Except for total nitrogen content, the contents of total solid, fat, NPN, lactose and ash were not significantly different between colostral, transitional and mature milk. Fatty acids did not vary over the three lactation stages, while unsaturated fatty acids accounted for 59.95–63.22% of the total fatty acids. Relatively low contents of vitamins were in the milk because the volunteer mothers did not take any vitamin supplementation over the entire lactation period. Besides sodium and phosphate, the concentrations of most minerals in the breast milk remained fairly constant across the three lactation stages.     

米糠发酵过程中脂肪酸组分及含量变化的研究

以新鲜米糠为原料,以料水比1:9(w:v)配成培养基,接入红曲(Monascus anka)M180和木耳(Auricularia auricular)A900,在30℃、200r/min摇床培养,培养时间分别为4d和7d。利用气相色谱法,对米糠发酵过程中脂肪酸组分及含量的变化进行分析。结果显示,米糠中主要脂肪酸为C16:0、C18:1、C18:2,占总脂肪酸的95.05%,C16:1、C18:1、C18:2等不饱和脂肪酸占总脂肪酸的80.09%,在红曲和木耳发酵过程中,脂肪酸含量一直呈下降趋势,总脂肪酸含量由最初的200.75mg/g分别下降至68.35mg/g和79.95mg/g,红曲M180比木耳A900利用脂肪酸速度快。发酵结束后,红曲发酵米糠和木耳发酵米糠中不饱和脂肪酸占总脂肪酸的比例分别为83.76%和80.84%,与发酵前相比,没有得到明显提高。利用红曲和木耳发酵米糠不能达到富集不饱和脂肪酸的目的,但可作为除去米糠中脂肪,抑制酸败的潜在途径。     

Inhibition of Shigella sonnei-induced epithelial barrier disruption by surface-layer associated proteins of lactobacilli from Chinese fermented food

Surface-layer associated proteins (SLAP) of Lactobacillus paracasei ssp. paracasei M5-L and Lactobacillus casei Q8-L were examined to identify the functional basis for their protection within intestinal epithelial cells. The results showed that SLAP of M5-L and Q8-L remained active in a trypsin solution and retained a 45-kDa protein band, similar to that observed in controls. In contrast, under conditions of simulated gastric juice, the SLAP were partially degraded. Inhibitory effects of SLAP on adherence of Shigella sonnei to HT-29 cells were assessed with use of exclusion, competition, and replacement assays. In response to M5-L at 50 μg/mL SLAP, an inhibition ratio of 33% was obtained, while for Q8-L at 400 μg/mL SLAP, the inhibition ratio was 48%. Hoechst 33258 test results showed that cells infected with S. sonnei and co-incubated with SLAP of M5-L and Q8-L were only partially apoptotic, with apoptosis rates of 37.67 and 43.67%, respectively. These levels of apoptosis were substantially lower than that observed with cells infected with S. sonnei alone. In addition, the SLAP of Q8-L and M5-L reduced downstream caspase-1 activity and further modified apoptotic cell damage. Finally, SLAP of M5-L and Q8-L were also able to prevent S. sonnei-induced membrane damage by inhibiting delocalization of zonula occludens (ZO)-1 and reducing the amount of occludin produced by S. sonnei.     

不同发酵方式泡菜理化指标及微生物数量变化的研究

以萝卜为主要原料采用自然发酵、乳酸菌制剂发酵、老坛水发酵三种不同发酵方式腌制泡菜,对比研究三种不同发酵方式泡菜、泡菜卤相关理化指标和微生物数量的动态变化.结果表明乳酸菌制剂发酵与其他两种发酵方式相比:泡菜卤后期pH低、总酸含量高,泡菜中后期总糖含量高、质构性优,泡菜卤中后期总菌数相对较低、乳酸菌数量明显增高、大肠菌群数明显降低,乳酸菌制剂发酵泡菜更具有优势性.     

Investigation of bacterial and fungal diversity in tarag using high-throughput sequencing

This is the first study on the bacterial and fungal community diversity in 17 tarag samples (naturally fermented dairy products) through a metagenomic approach involving high-throughput pyrosequencing. Our results revealed the presence of a total of 47 bacterial and 43 fungal genera in all tarag samples, in which Lactobacillus and Galactomyces were the predominant genera of bacteria and fungi, respectively. The number of some microbial genera, such as Lactococcus, Acetobacter, Saccharomyces, Trichosporon, and Kluyveromyces, among others, was found to vary between different samples. Altogether, our results showed that the microbial flora in different samples may be stratified by geographic region.     

内蒙古优质传统酸牛奶中乳球菌的发酵特性研究

通过酸度测定,从内蒙古优质传统酸牛奶中分离的11株乳球菌中筛选出7株发酵酸乳凝乳时间短和凝乳状态好的乳球菌,进一步研究这7株乳球菌在乳中的发酵特性。测定菌株在凝乳前的产酸特性、冷藏24 h后的质构特性及4℃冷藏期间的产酸特性及活菌数变化。结果表明:菌株KLDS 4.1109和KLDS 4.1110产酸能力、后酸化能力及质构特性最好,且其在4℃冷藏期间活菌数都能维持在106cfu/mL以上。可见菌株KLDS 4.1109和KLDS 4.1110能成为新型发酵菌种,具有很大的开发潜力。     

内蒙古牧区乳酸球菌的分离鉴定及耐药表型分析

为探明内蒙古牧区自然发酵乳制品中乳酸球菌对氟喹诺酮类药物的耐药情况,对采自内蒙古四子王旗和达尔罕茂明安联合旗牧区的自然发酵乳制品中的乳酸菌进行分离纯化,并用二倍稀释法测定其最小抑菌浓度(MIC),选取4株耐药和1株中介的乳酸球菌进行生理生化鉴定及16S rRNA同源性分析。MIC的测定结果显示,18株试验菌株对3种氟喹诺酮类药物均呈现不同程度的耐药,对左氧氟沙星、诺氟沙星、环丙沙星的耐药率均为88.9%。鉴定结果表明,选取的5株试验菌株中,SB4、SB26、DM41为屎肠球菌(Enterococcus faecium),DM22、DM33为坚强肠球菌(Enterococcus durans)。     

基于高通量测序分析内蒙古地区传统酸面团中细菌菌群的多样性

该研究利用Illumina Miseq高通量测序技术对内蒙古西、中、东地区传统酸面团样品中的细菌菌群多样性进行解析,并结合PICRUSt软件预测细菌功能的变化。结果表明,传统酸面团样品共产生1 230 198条高质量序列,得到656个操作分类单元（OTU）;3个地区酸面团样品共检出3个优势细菌门和11个优势细菌属,共有优势细菌门为厚壁菌门（Firmicutes）和变形菌门（Proteobacteria）,共有优势细菌属为乳杆菌属（Lactobacillus）、明串珠菌属（Leuconostoc）、魏斯氏菌属（Weissella）和芽孢杆菌属（Bacillus）,不同地区样品间细菌菌群多样性和丰度存在明显差异。传统酸面团样品中细菌菌群的主要功能为碳水化合物代谢、辅助因子和维生素代谢、氨基酸代谢、脂质代谢及萜类化合物和聚酮化合物代谢。     

基于高通量测序技术分析豆腐乳中微生物多样性

采用高通量测序技术对4种不同来源发酵豆腐乳中微生物的多样性和丰度进行比对分析。结果表明,纯种发酵与自然发酵豆腐乳样品微生物菌群多样性差异较大,从不同豆腐乳样品中共检测得到3个优势细菌门（平均相对丰度＞1%）、6个优势真菌门、13个优势细菌属和19个优势真菌属;共有优势细菌属为假单胞菌属（Pseudomonas）、乳杆菌属（Lactobacillus）、透明颤菌属（Vitreoscilla）、魏斯氏菌属（Weissella）、不动杆菌属（Acinetobacter）和明串珠菌属（Leuconostoc）,其中,假单胞菌属在自然发酵豆腐乳中平均相对丰度最高（62.05%）;共有优势真菌属为酵母属（Saccharomyces）、曲霉属（Aspergillus）、德巴利氏酵母属（Debaryomyces）、短梗霉属（Aureobasidium）、假丝酵母属（Candida）和有孢圆酵母属（Torulaspora）,其中酵母属在纯种发酵豆腐乳中平均相对丰度最高（44.42%）。