发酵剂对熏马肠成熟过程中生物胺含量变化的影响

利用从熏马肠中分离出的具有抑菌作用并可以产生物胺氧化酶的菌株,1株表皮葡萄球菌(Staphylococcus epidermidis),3株模仿葡萄球菌(Staphylococcus simulans)作为发酵剂加入到熏马肠,在熏马肠成熟过程中采用高效液相色谱检测不同发酵剂对生物胺含量变化的影响,进而阐明发酵剂对熏马肠中生物胺累积的控制作用。从研究结果可以看出,在马肠成熟过程中,B组对色胺、苯乙胺、腐胺、组胺、酪胺都有较显著的减少作用;C组对色胺、腐胺、尸胺、组胺、酪胺减少作用显著;D组对色胺、苯乙胺、腐胺、组胺、酪胺的减少作用显著;E组对组胺、苯乙胺、色胺的减少作用显著。添加发酵剂组对精胺、亚精胺的减少作用均不显著。结果表明,上述菌种对熏马肠成熟过程中生物胺产生有较好的抑制作用,具有肉品发酵剂的良好特性,为熏马肠以及其他发酵肉制品的工业化生产和安全性奠定了基础。     

大蒜精油对熏马肠中德氏乳杆菌产腐胺的影响机制

研究不同质量浓度大蒜精油对熏马肠中德氏乳杆菌产腐胺的影响机制。利用反转录实时荧光定量聚合酶链式反应技术分析供试菌在不同大蒜精油质量浓度下的胍基丁胺脱亚胺酶相关基因表达情况,使用超高效液相色谱连续48 h监测纯菌体系中的腐胺产量;并将德氏乳杆菌接入到含不同质量浓度大蒜精油的熏马肠中发酵28 d,期间取样测其菌落总数、pH值及腐胺积累量。结果表明：无论是在纯菌培养还是在熏马肠发酵过程中,大蒜精油都能明显抑制细菌的增长,在纯菌体系中会明显抑制pH值的下降,但对熏马肠的最终pH值影响不明显;大蒜精油对调节基因aguR的转录影响不明显,但能极显著抑制操纵子aguBDAC的转录（P＜0.01）;增加纯菌体系以及熏马肠发酵过程中的大蒜精油质量浓度均能明显减少腐胺的生成。     

熏马肠成熟过程中产生物胺氧化酶菌对生物胺作用的研究

该研究以从新疆熏马肠中筛选出来的6株产生物胺氧化酶菌株(鼠李糖乳杆菌、枯草芽孢杆、腐生葡萄球菌、木糖葡萄球菌、戊糖片球菌、植物乳杆菌)作为发酵剂加入熏马肠中,采用PCR-DGGE技术监测菌落动态变化,高效液相色谱法检测熏马肠中生物胺(色胺、腐胺、苯乙胺、组胺、酪胺、尸胺、精胺、亚精胺)含量变化。结果表明,在熏马肠成熟过程中发酵剂对生物胺有一定的抑制作用。其中以腐生葡萄球菌对色胺、腐生葡萄球菌对苯乙胺、木糖葡萄球菌对尸胺、鼠李糖乳杆菌对腐胺、腐生葡萄球菌对组胺和枯草芽孢杆菌对酪胺的抑制作用最为显著,减少程度分别为45.49%、57.54%、40.75%、51.03%、49.28%、64.33%。本研究为熏马肠以及其他发酵肉制品的提高安全性奠定了基础。     

新疆熏马肠中生物胺含量的调查

利用高效液相色谱丹磺酰氯柱前衍生法,检测了从新疆自治区4个县市采集的44个熏马肠中8种生物胺含量。结果显示:4.6%熏马肠样品的生物胺(BAs)总量超过FDA规定的1 000 mg/kg限量标准,色胺、酪胺和亚精胺含量在不同程度上超过生物胺安全用量标准,腐胺和尸胺含量与国外报道基本一致。     

发酵剂对熏马肠脂肪酶活力的影响

主要研究发酵剂对熏马肠发酵成熟过程中脂肪酶活力的影响。结果表明,酸性脂肪酶活力、中性脂肪酶活力、磷脂酶活力在发酵成熟过程中持续下降,并且发酵剂组的三种酶活力在添加发酵剂后显著高于空白组(p0.05)。通过相关性分析表明,在熏马肠发酵成熟过程中,发酵剂组中的三种酶活力与p H、水分含量及盐分含量呈极显著相关性(p0.01)。     

新疆伊犁传统熏马肠中葡萄球菌的分离及生长特性研究

本研究利用微生物选择培养分离方法获取伊犁哈萨克自治州熏马肠中优势菌种葡萄球菌(Staphylococcus),并研究其在不同pH值、不同盐浓度、不同亚硝酸浓度等条件下的生长特性。结果表明,熏马肠中分离得到的葡萄球菌,在pH值为6的情况下生长情况较好;葡萄球菌的生长随着盐浓度的增加而受到抑制,盐浓度5.50%下生长较好;在亚硝酸盐浓度为150 mg·L^-1时,葡萄球菌生长情况较好。本实验结果表明,熏马肠中优势菌种葡萄球菌具有优良微生物发酵剂的生长特性,为进一步研究本地熏马肠中的发酵剂提供理论基础。     

发酵肉制品中微生物对生物胺形成机理的影响研究

富含高蛋白质的食品中存在生物胺,发酵肉制品中蛋白质含量丰富可能存在高浓度的生物胺。微生物在不同发酵肉制品中的分布不尽相同,导致了在不同发酵肉制品中生物胺种类和数量上的差异。该文综述发酵肉制品中微生物对生物胺形成机理的研究进展,将发酵肉制品中的微生物群落构成与生物胺分析有机地结合起来,为利用发酵剂调控微生物菌群结构来降低生物胺潜在危害的应用提供科学依据。     

大蒜精油对屎肠球菌和粪肠球菌产苯乙胺和酪胺的影响

本试验采用双倍试管稀释法,测定大蒜精油分别对高产苯乙胺和酪胺的E.faecium和E.faecalis的最低抑菌浓度(MIC)和最低杀菌浓度(MBC);并利用高效液相色谱法测定不同浓度的大蒜精油对两株高产苯乙胺和酪胺菌株的影响,从而明确大蒜精油对其产生物胺能力的抑制作用。结果表明:大蒜精油对供试菌株都具有较强的抑菌活性,大蒜精油对E.faecium的最大抑制率可达48.20%,对E.faecalis的最大抑制率为52.41%,且抑菌效果随大蒜精油浓度的增大而逐渐增强;在大蒜精油的添加量为1/2 MIC时,大蒜精油对E.faecium和E.faecalis的生长具有抑制作用;当大蒜精油浓度为0.025%时,能够显著(p0.05)降低供试菌株产苯乙胺和酪胺的含量,苯乙胺含量与空白组相比降低了26.61%,酪胺的降低了15.54%。说明大蒜精油对高产酪胺和苯乙胺的菌株具有显著(p0.05)抑制效果,从而减少了酪胺和苯乙胺的生成。     

不同发酵方式对发酵马肉肠贮藏期品质劣变及食用安全性的影响

为有效确保发酵马肉肠贮藏期间的品质及安全性,研究添加汉逊德巴利酵母菌1808（Debaryomyces hansenii 1808）、木糖葡萄球菌21445（Staphylococcus xylose 21445）、植物乳杆菌E11（Lactobacillus plantarum E11）的复合发酵剂发酵组（FP）和单一乳酸菌发酵组（DZ）、自然发酵组（ZR）马肉肠贮藏过程中生物胺的变化,考察不同发酵方式对发酵马肉肠pH值、水分活度（aw）、色差、总挥发性盐基氮（total volatile basic nitrogen,TVB-N）含量、硫代巴比妥酸反应物（thiobarbituric acid reactive substances,TBARs）值及菌落总数的影响。结果表明：在贮藏期间,相比于自然发酵组和单一乳酸菌发酵组,添加复配发酵剂可有效减缓发酵马肉肠TVB-N含量、TBARs值、pH值的增幅,抑制贮藏后期有害杂菌的生长,防止产品过早发生腐败变质;此外,复配发酵剂可显著降低贮藏过程中马肉肠的水分损失（P＜0.05）,维持色泽的稳定,抑制生物胺（尸胺、腐胺、酪胺、组胺）的积累。综上,随着贮藏时间的延长,复配发酵剂可显著抑制发酵马肉肠品质的劣变及不良生物胺的过多积累。     

5株发酵剂对熏马肠成熟过程中内源菌的影响

使用经实验室分离鉴定的4株葡萄球菌(Staphylococcus epidermidis;Staphylococcus simulans.001;Staphylococcus simulans.002;Staphylococcus simulans.003)及1株植物乳杆菌(Lactobacillus plantarum),采取不同的纯菌及复合添加组合(4株葡萄球菌分别与植物乳杆菌1∶1的比例)作为发酵剂,在发酵和成熟的不同时期取样及提取熏马肠中细菌的总DNA,采用PCR-DGGE技术研究发酵剂对内源微生物在熏马肠成熟全过程中动态变化的影响。试验结果表明,不同发酵剂添加组合的熏马肠菌相分布呈现不同变化,但是随着成熟时间的增加,优势菌趋于明显,Weissella sp.,Lactobacillus sp.,Enterococus faecium,Enterococus faecalis始终存在于菌相中。其中F组(Staphylococcus simulans.002)的抑菌效果明显,内源菌的种类和数量都有所减少,尤其是对Lactobacillus plantarum,Pseudomonas sp.,Enterococus faecalis有较强的抑制作用。     

Safety improvement and preservation of typical sensory qualities of traditional dry fermented sausages using autochthonous starter cultures

Traditional dry fermented sausages are manufactured without addition of starter cultures in small-scale processing units, their fermentation relying on indigenous microflora. Characterisation and control of these specific bacteria are essential for the sensory quality and the safety of the sausages. The aim of this study was to develop an autochthonous starter culture that improves safety while preserving the typical sensory characteristics of traditional sausages. An autochthonous starter composed of Lactobacillus sakei, Staphylococcus equorum and Staphylococcus succinus isolated from a traditional fermented sausage was developed. These strains were tested for their susceptibility to antibiotics and their production of biogenic amines. This starter was evaluated in situ at the French traditional processing unit where the strains had been isolated. Effects of the autochthonous starter were assessed by analysing the microbial, physico-chemical, biochemical and sensory characteristics of the sausages. Inoculation with the chosen species was confirmed using known species-specific PCR assays for L. sakei and S. equorum and a species-specific PCR assay developed in this study for S. succinus. Strains were monitored by pulse-field gel electrophoresis typing. Addition of autochthonous microbial starter cultures improved safety compared with the traditional natural fermentation of sausages, by inhibiting the pathogen Listeria monocytogenes, decreasing the level of biogenic amines and by limiting fatty acid and cholesterol oxidation. Moreover, autochthonous starter did not affect the typical sensory quality of the traditional sausages. This is the first time to our knowledge that selection, development and validation in situ of autochthonous starter cultures have been carried out, and also the first time that S. equorum together with S. succinus have been used as starter cultures for meat fermentation. Use of autochthonous starter cultures is an effective tool for limiting the formation of unsafe compounds in traditional sausage while preserving their original and specific sensory quality.     

发酵香肠中生物胺含量影响因素的研究进展

介绍生物胺的种类、危害及在发酵香肠中存在的可能,重点分析了原料肉、发酵剂、工艺条件(温度、pH值、香肠直径、辅助配料、贮藏条件)等因子对发酵香肠中生物胺含量的影响,并提出了通过控制原料肉的卫生质量、使用优良的发酵剂、控制蛋白质的水解程度、使用添加剂等措施降低发酵香肠中生物胺含量。     

Biogenic amines in dry fermented sausages: a review

Biogenic amines are compounds commonly present in living organisms in which they are responsible for many essential functions. They can be naturally present in many foods such as fruits and vegetables, meat, fish, chocolate and milk, but they can also be produced in high amounts by microorganisms through the activity of amino acid decarboxylases. Excessive consumption of these amines can be of health concern because their not equilibrate assumption in human organism can generate different degrees of diseases determined by their action on nervous, gastric and intestinal systems and blood pressure. High microbial counts, which characterise fermented foods, often unavoidably lead to considerable accumulation of biogenic amines, especially tyramine, 2-phenylethylamine, tryptamine, cadaverine, putrescine and histamine. However, great fluctuations of amine content are reported in the same type of product. These differences depend on many variables: the quali-quantitative composition of microbial microflora, the chemico-physical variables, the hygienic procedure adopted during production, and the availability of precursors. Dry fermented sausages are worldwide diffused fermented meat products that can be a source of biogenic amines. Even in the absence of specific rules and regulations regarding the presence of these compounds in sausages and other fermented products, an increasing attention is given to biogenic amines, especially in relation to the higher number of consumers with enhanced sensitivity to biogenic amines determined by the inhibition of the action of amino oxidases, the enzymes involved in the detoxification of these substances. The aim of this paper is to give an overview on the presence of these compounds in dry fermented sausages and to discuss the most important factors influencing their accumulation. These include process and implicit factors as well as the role of starter and nonstarter microflora growing in the different steps of sausage production. Moreover, the role of microorganisms with amino oxidase activity as starter cultures to control or reduce the accumulation of biogenic amines during ripening and storage of sausages is discussed.     

Analysis of biogenic amines in northern and southern European sausages and role of flora in amine production

The biogenic amine contents, microbial counts and flora producing amines were investigated in four types of fermented sausages. Southern type European sausages (Italian and Belgian) showed higher tyramine and phenylethylamine values than northern type ones (Norwegian and Belgian). The spontaneous non-starter lactic acid bacteria could be responsible for the production of these amines in the Italian products, and the cocci Gram positive in the Belgian South ones. The Norwegian sausages showed the lowest total amine content of those studied. The two Belgian types were characterised by the highest putrescine contents, associated with high counts of Enterococcus. The production of amines in vitro by the starter cultures used in the manufacture of the sausages revealed that none of the Lactobacillus species produced any amines and only Kocuria varians and Staphylococcus carnosus showed phenylethylamine and tryptamine production. High correlations were found between the content of putrescine, histamine and cadaverine.     

Mixed starter cultures to control biogenic amine production in dry fermented sausages

Several combinations of an amine-negative Lactobacillus sakei strain, along with proteolytic Staphylococcus carnosus or Staphylococcus xylosus strains, were used to study the influence of mixed starter cultures on biogenic amine production during the manufacture of dry fermented sausages. Changes in pH, water content, proteolysis, microbial counts, and biogenic amine contents were simultaneously examined in a spontaneously fermented batch and in three mixed starter-mediated batches. A double-controlled microbial charge initially inoculated as mixed starter culture of L. sakei and Staphylococcus spp. (all amine-negative strains) drastically reduced tyramine, cadaverine, and putrescine accumulation. No production of other aromatic amines such as histamine, phenylethylamine, or tryptamine was observed in any batch. The polyamines, spermine and spermidine, were found in raw materials and their levels decreased slightly in the spontaneously fermented batch. No correlation between proteolysis and biogenic amine production was observed. The use of proper technological conditions favoring starter development and the use of the raw materials with good hygienic quality make it possible to produce fermented sausages nearly free of biogenic amines.     

Novel starter cultures to inhibit biogenic amines accumulation during fish sauce fermentation

Bacteria with amine oxidase activity have become a particular interest to reduce biogenic amines concentration in food products such as meat and fish sausages. However, little information is available regarding the application of these bacteria in fish sauce. Hence, our study was aimed to investigate the effect of such starter cultures in reducing biogenic amines accumulation during fish sauce fermentation. Staphylococcus carnosus FS19 and Bacillus amyloliquefaciens FS05 isolated from fish sauce which possess amine oxidase activity were used as starter cultures in this study. Fermentation was held for 120 days at 35 °C. The pH value increased in all samples, while salt concentration remained constant throughout fermentation. Aerobic bacteria count was significantly lower (p < 0.05) in the control than in inoculated samples as a result of starter cultures addition. However, it decreased during fermentation due to the growth inhibition by high salt concentration. Proteolytic bacterial count decreased during fermentation with no significant difference (p > 0.05) among samples. These bacteria hydrolyzed protein in anchovy to produce free amino acid precursors for amines formation by decarboxylase bacteria. The presence of biogenic amines producing bacteria in this study was considered to be indigenous from raw material or contamination during fermentation, since our cultures were negative histamine producers. Amino acid histidine, arginine, lysine and tyrosine concentration decreased at different rates during fermentation as they were converted into their respective amines. In general, biogenic amines concentration namely histamine, putrescine, cadaverine and tyramine increased throughout fermentation. However, their concentrations were markedly higher (p < 0.05) in the control (without starter cultures) as compared to the samples treated with starter cultures. Histamine concentration was reduced by 27.7% and 15.4% by Staphylococcus carnosus FS19 and Bacillus amyloliquefaciens FS05, respectively. Both cultures could also reduce other amines during fermentation. After 120 days of fermentation, the overall biogenic amines concentration was 15.9% and 12.5% less in samples inoculated with Staphylococcus carnosus FS19 and Bacillus amyloliquefaciens FS05, respectively, as compared to control samples. These findings emphasized that application of starter cultures with amines oxidase activity in fish sauce fermentation was found to be effective in reducing biogenic amines accumulation.     

Use of Fourier transform infrared spectroscopy to evaluate the proteolytic activity of Yarrowia lipolytica and its contribution to cheese ripening

The interaction between tyrosine-decarboxylase and proteolytic activities of a Lactobacillus curvatus and Staphylococcus xylosus, respectively, on biogenic amine production during the ripening and the storage of dry fermented sausages was investigated. Water content, pH, proteolysis parameters, microbial counts, and biogenic amine contents were monitored in spontaneously and starter fermented sausages. The use of proteolytic staphylococci as starter resulted in a higher content of non-protein nitrogen and total free amino acids. Tyramine was the main amine produced in all batches. However, tyrosine-decarboxylase activity of the L. curvatus starter strain was weak and yielded lower amounts of tyramine than those produced by the wild mioroflora in the control batch. Association between tyramine production and proteolysis could only be established in a defectively dried batch. Putrescine and cadaverine accumulation was efficiently reduced in the starter-mediated fermentation, in agreement with the lower development of enterobacteria. Phenylethylamine and tryptamine were only detected in the spontaneously fermented sausages, while histamine, spermine and spermidine did not vary during the ripening. Biogenic amine levels and related parameters showed significant changes during the storage of dry sausages depending on the temperature and the batch. As a general rule, changes in the pH, proteolysis, microbial counts, and biogenic amine contents were stronger at 19 degrees C than at 4 degrees C. The results suggest that refrigeration would be advisable for preventing further accumulation of biogenic amines during the storage of dry fermented sausages.     

传统发酵肉制品中降解生物胺菌株的筛选鉴定与应用研究

该研究利用高效液相色谱（HPLC）法对65株来源于传统发酵肉制品的耐盐、耐亚硝酸盐乳酸菌所产生物胺进行定性定量检测,筛选出降解率最高的不产生物胺菌株PL-ZL001。经形态观察、生理生化试验研究,并结合16S rDNA序列分析对其进行鉴定,同时探索其作为发酵剂对发酵香肠中生物胺含量的影响。结果表明,菌株PL-ZL001被鉴定为植物乳杆菌（Lactobacillus plantarum）,添加菌株PL-ZL001可抑制发酵香肠中6种生物胺的积累,尤其是对毒性最大的组胺含量的控制,效果显著优于商业用木糖葡糖球菌（Staphyloccus xylose）（P＜0.05）。     

Formation of Biogenic Amines during Ripening of Dry Sausages as Affected by Starter Culture and Thawing Time of Raw Materials

Raw materials affect formation of biogenic amines in dry sausages. Effects of thawing time of raw materials and amine-negative starter culture on amine formation were studied on a pilot scale. The levels of biogenic amines, precursor amino acids, pH, water activity, and microbial counts were measured. Use of starter culture significantly decreased levels of histamine, tyramine and cadaverine formed. The effect of thawing time on formation of biogenic amines was dependent on the use of starter culture.