常温条件下白鱼中特定腐败菌的鉴定

通过分析常温条件下无菌白鱼鱼块（CK）以及接种不同腐败菌的无菌白鱼鱼块的感官评价、挥发性盐基氮（total volatile base nitrogen,TVBN）值、腐败菌生长动态以及pH值的变化,以腐败菌的生长动力学参数和TVBN产量因子（YTVBN/CFU）为定量指标,鉴定了常温条件下导致白鱼腐败的特定腐败菌（specific spoilage organism,SSO）。结果表明,在CK和接种葡萄球菌wf-1（Staphylococcus sp.wf-1）、摩根氏菌wf-1（Morganella sp.wf-1）、摩根氏菌wf-2（Morganella sp.wf-2）、变形杆菌wf-1（Proteus sp.wf-1）、变形杆菌wf-2（Proteus sp.wf-2）和变形杆菌wf-3（Proteus sp.wf-3）的无菌白鱼鱼块中,以接种Morganella sp.wf-1的无菌白鱼鱼块达到感官拒绝点的时间最短,为15.16 h,此时鱼块的TVNB含量和菌落总数分别为29.98 mg/100 g和7.53（lg（CFU/g））。对这些腐败菌的生长动力学参数和YTVBN/CFU分析发现,Morganella sp.wf-1在无菌白鱼鱼块上的生长延滞期最短,为2.60 h;最大比生长速率最大,为0.304 6 h－1;YTVBN/CFU最大,为6.27×10－9 mg TVBN/CFU。所有白鱼鱼块均出现pH值先下降后上升的过程,其中接种Morganella sp.wf-1和Morganella sp.wf-2的无菌鱼块在8～48 h之间的pH值远远高于CK和接种其他腐败菌的无菌白鱼鱼块。结合实验数据和SSO的概念,最终确定Morganella sp.wf-1为常温条件下导致白鱼腐败的SSO。     

黄酒酒曲中产生物胺细菌的分离鉴定

为探明黄酒酒曲中产生物胺细菌的菌相,深入研究黄酒中的生物胺形成机制,分别以4种黄酒酒曲(麦曲M、麦曲L、小曲Q、红曲H)为研究对象,采用脱羧酶培养基对产生物胺细菌进行初筛,高效液相色谱法复筛,并通过16S rDNA基因序列分析,对分离得到的产生物胺细菌进行鉴定。共筛选出42株产生物胺细菌,包括肠杆菌属(Enterobacter sp.)17株,乳杆菌属(Lactobacillus sp.)6株,克雷伯氏菌属(Klebsiella sp.)5株,沙门氏菌属(Salmonella sp.)4株,肠球菌属(Enterococcus sp.)3株,克罗诺菌属(Cronobacter sp.)3株,埃希菌属(Escherichia sp.)菌株2株,柠檬酸杆菌属(Citrobacter sp.)1株,葡萄球菌属(Staphylococcus sp.)1株。分离的产生物胺细菌中多数可同时产生多种生物胺,其中产腐胺、尸胺、组胺的菌最多,但未分离到色胺和亚精胺产生菌。     

3 种添加物对咸鱼加工贮藏过程中生物胺的抑制效果

为解决咸鱼加工、贮藏过程中生物胺的安全问题,本研究在咸鱼加工过程分别添加3 种食用级添加物（山梨酸钾、姜辣素、混合乳酸菌液）,采用生物胺初筛培养基检测产生物胺微生物的变化,高效液相色谱法检测咸鱼中腐胺、尸胺、组胺、酪胺等含量变化,比较3 种添加物对咸鱼中生物胺的抑制效果。结果表明：腌制后的咸鱼,在干燥过程和贮藏过程产生物胺菌数量和生物胺含量较高,3 种添加物均对咸鱼中生物胺的产生有一定抑制效果。其中,山梨酸钾对咸鱼中腐胺和尸胺的抑制效果最显著,抑制率分别为65.30%和69.77%,姜辣素对咸鱼中组胺的抑制效果最显著,抑制率为76.75%,乳酸菌对腐胺、尸胺和组胺有一定的抑制效果,但不及山梨酸钾和姜辣素;3种添加物对酪胺有一定的抑制效果,但均不明显。     

4℃、20℃贮藏下鲍鱼品质变化

以新鲜鲍鱼为原料,应用选择培养基、高效液相色谱技术等对贮藏期间的微生物、生物胺及相关理化指标(感官评价、挥发性盐基氮(Total volatile basic nitrogen,TVB-N)、pH值)进行测定,研究4℃、20℃贮藏下鲍鱼品质劣变的优势菌以及危害因子生物胺的产生情况。2种贮藏温度下,假单胞菌和腐败希瓦氏菌均为优势腐败菌,腐胺、尸胺含量和TVB-N值、总菌落数、假单胞菌、腐败希瓦氏菌数量有良好的相关性(R2=0.983~0.914),尸胺、腐胺可以作为鲍鱼品质评价的参考指标,4℃可以有效抑制鲍鱼的腐败进程,延长鲍鱼保质期。     

黄酒酿造过程中优势细菌产生物胺的检测与评价

采用显色培养基法、脱羧酶序列特异PCR技术和HPLC分析脱羧酶液体培养基生物胺含量变化3种方法检测和评价来自黄酒酿造过程的41株细菌产生物胺的情况。研究表明,3种方法检测结果大致相同,互补使用能够准确分析细菌产生物胺的情况;41株细菌中,53.7%以上都能产酪胺,31.7%以上产腐胺,24.3%以上产组胺;14株短乳杆菌均携带酪氨酸脱羧酶基因,其中11株菌的酪胺产量超过50.00 mg/L,且多数菌能代谢产生多种生物胺,因此推断其对黄酒中生物胺含量影响最大;细菌代谢是否产生物胺及产生物胺的能力无种属特异性,但有菌株特异性。     

四川泡菜产生物胺细菌的筛选及产胺能力验证

以四川工业泡菜和家庭泡菜为研究对象,分析其一般理化性质、微生物数量及生物胺含量,并对产生物胺细菌进行筛选及产胺能力验证。结果表明,四川工业泡菜的盐度较高,为(11.15±0.11)mg/kg,菌落总数及乳酸菌总数较低,家庭泡菜的pH较低,总酸含量较高,分别为(3.55±0.04),(1.30±0)g/100g。腐胺、尸胺、组胺、酪胺为四川泡菜主要的生物胺,含量均超过100mg/kg,且在四川工业泡菜中,尸胺含量高达(349.43±13.23)mg/kg。从四川泡菜中筛选出11株产生物胺的细菌,经鉴定分别为解鸟氨酸拉乌尔菌(Raoultella ornithinolytica)、弗氏柠檬酸杆菌(Citrobacter freundii)、特基拉芽孢杆菌(Bacillus tequilensis)、阿耶波多氏芽孢杆菌(Bacillus aryabhattai),其中R.ornithinolytica含有赖氨酸脱羧酶cacd基因和组氨酸脱羧酶hdc基因,且回接培养基验证了其具有尸胺和组胺形成能力,48h尸胺形成量高达(766.67±2.17)mg/L,可能是四川工业泡菜尸胺含量较高的原因。文章研究结果可为四川泡菜生物胺含量的调控提供参考。     

高效液相法测定草鱼糜发酵过程中生物胺变化

本文采用纳豆芽孢杆菌和戊糖片球菌组成的混合发酵剂对草鱼鱼糜进行发酵,建立了发酵鱼制品中六种生物胺(色胺、腐胺、尸胺、组胺、酪胺、亚精胺)的高效液相色谱分析方法,研究了鱼糜发酵过程中生物胺含量的变化以及微生物数量的变化。结果发现,在30 min内各种生物胺得到很好的分离,且线性关系良好(R20.999),回收率在97.35%~103.00%,精密度、重现性RSD均小于10%。添加混合发酵剂可以明显抑制金黄色葡萄球菌、假单胞菌和大肠杆菌等杂菌的生长,降低发酵过程中腐胺、尸胺、组胺和酪胺含量的积累;利用纳豆芽孢杆菌,戊糖片球菌组成的混合发酵剂以及一系列负控脱羧酶活动能有效抑制鱼糜发酵过程中生物胺的形成,抑制腐败菌和致病菌的生长,提高鱼糜发酵食品的品质。     

海水鱼优势腐败菌腐败能力分析

研究大黄鱼和大菱鲆无菌鱼块接种优势腐败菌后5℃贮藏中的感官、腐败产物和腐败菌的变化,以生长动力学参数和腐败产物的产量因子(YTVBN/CFU和YTMA/CFU)为指标,探讨两种冷藏海水鱼优势腐败菌希瓦氏菌和假单胞菌的腐败能力。结果表明,大菱鲆鱼块接种腐败希瓦氏菌和恶臭假单胞菌的货架期分别为60,72h,货架期终点时的TVBN含量分别为35.48,37.56mg/100g,腐败菌菌数分别为8.14,8.32lg(CFU/g),产量因子YTVBN/CFU分别为1.86×10-7,1.35×10-7 mg TVBN/CFU。大黄鱼鱼块接种腐败希瓦氏菌和荧光假单胞菌的货架期分别为162,174h,货架期终点时的TVBN含量分别为31.74,39.01mg/100g,腐败菌菌数分别为8.71,8.91lg(CFU/g),产量因子YTVBN/CFU分别为4.49×10-8,3.72×10-8 mg TVBN/CFU。大黄鱼鱼块的货架期比大菱鲆的明显长,接种假单胞菌的两种鱼块的货架期比接种希瓦氏菌的稍长。两种海水鱼低温有氧贮藏优势腐败菌希瓦氏菌和假单胞菌都有很强的腐败能力。     

海产品中蜂房哈夫尼菌的鉴定及相关特性研究

从蜢虾酱和鱼露中分离出3株和1株细菌,命名为G1、G4、G5和Y1。经16S rRNA序列分析和相关生理、生化鉴定,4株菌均为蜂房哈夫尼菌。为探究海产品中蜂房哈夫尼菌的腐败相关特性,测定这4株以及另分离自腐败即食海参和大菱鲆的2株蜂房哈夫尼菌生物被膜的形成、泳动性、耐盐性、耐药性、TVB-N值和生物胺产生能力等相关特性。结果表明,6株蜂房哈夫尼菌具有较强的耐盐度,均在0.05 g/mL以上,培养一定时间后形成中等强度以上的生物被膜,并可在泳动性培养基表面扩散,表明其具有泳动性。该菌具有广泛的抗药性,对氨苄青霉素、壮观霉素、磺胺二甲嘧啶、磺胺嘧啶等抗菌药物有不同程度的抗性,然而对庆大霉素、四环素、氯霉素、卡那霉素、氧氟沙星、环丙沙星和呋喃唑酮较为敏感。将6株菌分别接种到其相应来源的海产品后,其TVB-N值随着贮藏时间的延长而明显增加。此外,6株蜂房哈夫尼菌均能产生3种生物胺,分别为腐胺、尸胺和组胺,并且产生腐胺和尸胺的能力明显高于组胺,说明蜂房哈夫尼菌具有腐败特性,在海产品腐败过程中起重要作用。本研究在探索蜂房哈夫尼菌导致的海产品腐败方面具有重要意义。     

混合菌种发酵生产低酸度川味香肠加工过程中生物胺含量的变化

接种混合发酵剂并在控温控湿条件下生产低酸度川味香肠,对加工过程中生物胺(色胺、苯乙胺、腐胺、尸胺、组胺、酪胺和亚精胺)含量变化进行研究。结果表明:干燥结束时,低酸度川味香肠中除亚精胺以外,其他生物胺含量均低于人工控温控湿不接种组(B组)、自然条件接种组(C组)、自然条件不接种组(D组),其中色胺、苯乙胺、腐胺、组胺和酪胺的含量均显著低于未接种组(P0.01),说明混合发酵剂在适宜的温湿度条件下能明显抑制低酸度川味香肠中色胺、苯乙胺、腐胺、组胺和酪胺积累(P0.01);混合发酵剂对低酸度川味香肠中尸胺的抑制作用不显著(P0.05)。     

Biogenic amine production by<Emphasis Type="Italic"> Morganella morganii</Emphasis> and<Emphasis Type="Italic"> Klebsiella oxytoca</Emphasis> in tuna

Biogenic amine formation in tuna inoculated with two micro-organisms reported as powerful in vitro histamine producers, Morganella morganii and Klebsiella oxytoca, was investigated. Inoculated and non-inoculated tuna samples were stored in ice, under refrigeration at 8–10 °C and at 20±1 °C. Ten biogenic amines were studied and changes were found only in cadaverine and histamine in inoculated samples. Therefore, the in vitro ability of K. oxytoca to form cadaverine and that of both microorganisms to form histamine was confirmed in inoculated samples. Storage temperature had a crucial effect on the amount and intensity of amine production. On the other hand, the potential ability of M. morganii to form putrescine was not shown in the inoculated samples, regardless of the storage temperature.     

Biogenic amine index for freshness evaluation in iced Mediterranean hake (Merluccius merluccius)

Biogenic amine accumulation was studied during the ice storage of Mediterranean hake. Sensory analysis and counts of Shewanella, Pseudomonas, enterobacteria, psychrotrophic, and mesophilic bacteria provided complementary information on hake spoilage. Putrescine and cadaverine were the main amines accumulated, whereas histamine and tyramine were minor amines but had qualitative interest from the hygienic point of view. Although all biogenic amines were less abundant than in pelagic fish, they may also be used as indicators of freshness and/or spoilage in hake. Cadaverine was the amine best correlated with Shewanella, which was the specific spoilage organism. Therefore, cadaverine may be regarded as the specific spoilage biogenic amine for hake stored at chilling temperatures. However, the biogenic amine index, which considers cadaverine, putrescine, histamine, and tyramine, has several advantages as an indicator of hake quality. Taking into account sensory data, an acceptability limit of the biogenic amine index could be established in 15 to 20 microg/g.     

BIOGENIC AMINES IN FINNISH DRY SAUSAGES

A study was conducted to determine the biogenic amine levels of Finnish dry sausages and to compare the results with those of other surveys of different types of fermented sausages. Sausages with high amine concentration were analyzed microbiologically in order to identify amine-producing microorganisms. Tyramine was the most common amine: the mean of 68 samples was 82 mg/kg and the mode 110 mg/kg. Other vasoactive amines found were histamine (<1–200 mg/kg), phenylethylamine (<1–48 mg/kg) and tryptamine (<10–91 mg/kg). Increased amounts of the spoilage indicator amines putrescine and cadaverine were found from most of the samples containing vasoactive amines. The formation of amines can be linked with problem(s) in hygienic conditions of raw materials and manufacturing practices and it is thus proposed that the sum of tyramine, histamine, putrescine and cadaverine could serve as an indicator of quality in fermented meat products.     

Biogenic amines and their producers in Akawi white cheese

The aim of this work was to study the biogenic amine content of brine‐ripened cheeses after one year of storage and then to investigate possible contaminating micro‐organisms with decarboxylase activity. The biogenic amine production of isolates was tested in vitro. The most frequent biogenic amines were putrescine, histamine and tyramine. The biogenic amine content detected in one cheese sample was above 120 mg/kg; this can be considered toxicologically relevant. Decarboxylase activity was found for 33 contaminating micro‐organisms. Isolates belonging to Bacillus licheniformis, Debaryomyces hansenii, Staphylococcus equorum and Serratia marcescens produced significant amounts of putrescine and cadaverine.     

Biogenic Amine Content of Beers Consumed in Turkey and Influence of Storage Conditions on Biogenic Amine Formation

The biogenic amine content of beers available in Turkey, both domestic production and imported products, was investigated. A total of 17 domestic and 13 imported beers were evaluated in terms of 8 different biogenic amines (histamine, tyramine, spermine, spermidine, 2‐phenylethylamine, putrescine, tryptamine and cadaverine). HPLC methodology with pre‐column derivatization and photodiode array detection after derivatization with dansyl chloride was used for quantification. In addition, the evolution of important amines such as histamine, tyramine, putrescine and cadaverine were investigated during different storage conditions by response surface methodology. The results indicated that both storage temperature and storage time were important factors affecting biogenic amine content. Histamine and putrescine increased during storage, but then decreased after reaching a maximum level after six weeks. With the biogenic amines tyramine and cadaverine, the amounts increased during the entire storage period. At higher storage temperatures, the formation of biogenic amines increased.     

Production of Biogenic Amines and Their Potential Use as Quality Control Indices for Hake (Merluccius merluccius, L.) Stored in Ice

ABSTRACT: The production of tyramine, histamine, putrescine, cadaverine, agmatine, and spermidine was studied for use as quality indices in muscle of gutted hake stored in ice for 25 d. The changes in biogenic amine concentrations were correlated with trimethylamine nitrogen levels. All concentrations except for spermidine, increased progressively throughout storage. During storage, cadaverine reached 72.14 mg/kg while there were no significant increases in histamine and tyramine. The levels of free amino acids, which may be metabolized into biogenic amines, were not correlated to respective biogenic amines levels. The production of cadaverine and agmatine occurred prior to spoilage and these biogenic amines may indicate freshness of hake stored in ice.     

Amino acid-decarboxylase activity of bacteria isolated from fermented pork sausages.

The occurrence of amino acid-decarboxylase activity in 92 strains of lactic acid bacteria, coagulase-negative staphylococci, and Enterobacteriaceae isolated from Spanish fermented pork sausages was investigated. The presence of biogenic amines in a decarboxylase synthetic broth was determined by ion-pair high performance liquid chromatography with o-phtalaldehyde post-column derivatization. Among the 66 lactic acid bacteria strains tested, 21 lactobacilli (in particular, Lactobacillus curvatus) and all 16 enterococci were amine producers. Tyramine was the main amine produced by these bacteria, although they also produced phenylethylamine, tryptamine, and/or the diamines putrescine and cadaverine. None of the lactic acid bacteria produced histamine. Coagulase-negative staphylococci were found to be negative amine-producers. Aromatic monoamines, apart from histamine, were not formed by Enterobacteriaceae. This family was responsible for cadaverine and putrescine production. The results obtained for biogenic amine production by bacteria in a synthetic medium suggest that amino acid-decarboxylase activity is strain dependent rather than being related to specific species.     

Histamine and biogenic amine production by Morganella morganii isolated from temperature-abused albacore

Histamine-producing bacteria were isolated from albacore stored at 0, 25, 30, and 37 degrees C. They were screened using Niven's differential medium, and their histamine production was confirmed by high-pressure liquid chromatography analysis. The optimum temperature for growth of histamine-producing bacteria was 25 degrees C. The bacterium producing the highest level of histamine was isolated from fish abused at 25 degrees C. It was identified as Morganella morganii by morphological, cultural, biochemical, and antimicrobial characteristics and by the Vitek microbial identification system. The M. morganii isolate was inoculated into tuna fish infusion broth medium, and the effect of temperature was determined for microbial growth and formation of histamine and other biogenic amines. The isolate produced the highest level of histamine, 5,253 ppm, at 25 degrees C in the stationary phase. At 15 degrees C, histamine production was reduced to 2,769 ppm. Neither microbial growth nor histamine formation was detected at 4 degrees C. To determine whether the isolate can also produce other biogenic amines that can potentiate histamine toxicity, production of cadaverine, putrescine, serotonin, tryptamine, tyramine, phenylethylamine, spermidine, and spermine by the isolate was also monitored. Cadaverine, putrescine, and phenylethylamine were detected with microbial growth in the tuna fish infusion broth medium. The optimum temperature for cadaverine, putrescine, and phenylethylamine formation was found to be 25 degrees C, as it was for histamine.