不同NaCl添加量对牦牛乳硬质干酪成熟过程中生物胺产生的影响

以不同盐添加量（1.0%、1.3%、1.8%和2.3%）牦牛乳硬质干酪为研究对象,分析牦牛乳硬质干酪0～6 个月成熟过程中生物胺的动态变化,并对干酪中产胺微生物进行筛选。结果显示：不同盐添加量牦牛乳硬质干酪中生物胺主要为色胺、β-苯乙胺、尸胺、酪胺和腐胺,未检测到组胺,生物胺积累阶段主要集中在成熟后期。不同盐添加量干酪中色胺含量最低,且在成熟后期含量差异较小。当盐添加量从2.3%减少到1.0%时,干酪中β-苯乙胺含量减少。盐添加量分别为1.0%和1.3%时,干酪中尸胺含量较低,且未检测出腐胺。当盐添加量在1.8%～2.3%时,随着盐添加量的增加,干酪中尸胺和腐胺含量整体呈现增加趋势。不同盐添加量干酪成熟过程中,其酪胺含量范围为3.13～49.81 mg/kg,且盐添加量为1.3%干酪中酪胺含量较高。不同盐添加量干酪中生物胺总量最高为304.18 mg/kg。采用显色培养基筛选出一株产胺微生物,经分子生物学鉴定为Enterococcus durans。     

混合发酵剂对川味香肠发酵成熟过程中生物胺含量变化的影响

以植物乳杆菌、戊糖片球菌和葡萄球菌作为发酵剂接种至川味香肠,采用高效液相色谱法测定川味香肠发酵成熟过程中生物胺含量的变化。结果表明:成熟结束时,除苯乙胺外,A组(接种组)中的色胺、腐胺、尸胺、组胺、酪胺和亚精胺的含量显著低于B组(自然发酵组)(P0.01),说明混合发酵剂能显著抑制川味香肠发酵成熟过程中生物胺的形成(P0.01)。A组香肠在发酵成熟过程中除酪胺含量最高达到103.05 mg/kg外,其余生物胺含量均低于100 mg/kg;B组香肠在发酵成熟过程中腐胺、尸胺、组胺和酪胺含量超过100 mg/kg,因此接种混合发酵剂可以更好地保障川味香肠的安全性。     

冷藏乳制作的牦牛乳硬质干酪成熟过程中生物胺含量的变化

目的:揭示冷藏原料乳制作的干酪成熟过程中生物胺含量变化规律,评价其质量安全性。方法:以冷藏24,48,72 h牦牛乳制作的硬质干酪为研究对象,利用高效液相色谱法对干酪成熟过程中生物胺含量进行测定。结果:在0～6个月成熟过程中,不同冷藏牦牛乳制作的硬质干酪中生物胺含量呈升高趋势。牦牛乳冷藏时间从24 h延长到72 h时,其干酪中总生物胺、2-苯乙胺、尸胺、酪胺和腐胺含量也依次增大。成熟4个月后,冷藏72 h牦牛乳制作的硬质干酪中各生物胺含量明显高于其余两组干酪。成熟6个月时,冷藏72 h原料乳制作的牦牛乳硬质干酪中生物胺总量和酪胺含量分别为(212.94±8.03),(81.04±3.92) mg/kg。结论:随着原料乳冷藏时间和干酪成熟时间的延长,干酪中生物胺含量增多,但是原料乳冷藏时间低于72 h时,其干酪中生物胺含量低于学者建议含量。     

牦牛乳硬质干酪成熟过程中生物胺与细菌群落结构分析

成熟干酪易产生生物胺,生物胺对人体健康具有影响,因此,为了探究牦牛乳硬质干酪的质量安全性,本实验利用高效液相色谱和高通量测序技术对干酪成熟过程中生物胺和细菌群落结构进行测定和分析。结果表明：牦牛乳硬质干酪中主要生物胺为腐胺、2-苯乙胺、酪胺、组胺和尸胺,在1～6 个月成熟过程中,干酪中各生物胺含量呈现增加趋势。干酪中生物胺含量最高阶段均出现在成熟期5～6 个月。干酪中组胺、酪胺和总生物胺含量分别低于推荐安全剂量50、100 mg/kg和1 000 mg/kg。干酪中游离氨基酸含量与除组胺之外的各生物胺含量、总生物胺含量、成熟时间之间具有显著正相关性（P＜0.01,P＜0.05）,各生物胺含量之间也存在正相关性。不同成熟期干酪包含相同属的微生物,其中链球菌属（Streptococcus）为优势菌属,平均相对丰度为84.63%,明串珠菌属（Leuconostoc）次之,平均相对丰度为6.91%,其他分别为乳杆菌属（Lactobacillus）、拉乌尔菌属（Raoultella）、不动杆菌属（Acinetobacter）、假单胞菌属（Pseudomonas）、肠杆菌属（Enterobacter）和无分类的肠杆菌科（unclassified_Eunnterobacteriaceae）。不同成熟期干酪中各菌属的相对丰度具有差异。本研究可为评估牦牛乳硬质干酪的质量安全性和生物胺形成机理提供理论依据。     

市售四川香肠中生物胺含量比较分析

利用高效液相色谱,以丹磺酰氯为衍生试剂,分析了四川地区30种市售四川香肠中色胺、苯乙胺、腐胺、尸胺、组胺、酪胺和亚精胺的含量。结果表明:30种市售四川香肠中7种生物胺的检出率均为100%,其中组胺含量最高,平均为182.69 mg/kg;酪胺、尸胺和腐胺次之,平均含量分别为176.93、163.40和60.88 mg/kg;亚精胺平均含量最低,为7.68 mg/kg。30种四川香肠中生物胺的总含量为335.76~1 267.13 mg/kg,1号样品的生物胺总量最高,1、2、5、13、14、15和16号样品中尸胺、组胺和酪胺含量均超过100 mg/kg,存在一定的安全隐患。     

传统自然发酵四川香肠加工贮藏过程中生物胺含量变化

采用高效液相色谱法对传统自然发酵四川香肠加工贮藏过程中生物胺(色胺、苯乙胺、腐胺、尸胺、组胺、酪胺和亚精胺)含量变化进行测定。结果表明:传统自然发酵四川香肠原料肉中只检测出了色胺、苯乙胺和亚精胺,贮藏120天检测出了7种生物胺,除亚精胺外,6种生物胺(色胺、苯乙胺、腐胺、尸胺、组胺和酪胺)的含量在加工过程中均显著增加(P0.01)。传统自然发酵四川香肠中以酪胺、组胺、尸胺和腐胺为主,含量分别达到153.06、127.90、132.46和92.83 mg/kg,4种生物胺占生物胺总量的89.66%。传统自然发酵四川香肠中生物胺(色胺、苯乙胺、组胺和酪胺)含量均低于20 mg/100 g。生物胺总量在加工贮藏过程中变化显著(P0.01),总量低于1 000 mg/kg。     

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)。     

我国传统干酪中生物胺含量检测分析

通过反相高效液相色谱法对来自内蒙古、新疆、西藏、云南、北京市场共17种中国传统干酪样品生物胺含量进行了分析。结果表明,反相高效液相色谱法能准确地测定干酪中生物胺含量;在全部干酪样品中,8种生物胺含量大小不一,生物胺总量在1.30～41.27 mg/kg范围内,均低于国家标准规定要求,其中有14个样品的生物胺总量低于10 mg/kg,第10号干酪生物胺含量为41.27 mg/kg,为所有样品中含量最高,其次为第1号样品和第9号样品,分别为18.48 mg/kg和10.35 mg/kg。相关性分析结果显示,色胺与苯乙胺,腐胺与尸胺、酪胺、亚精胺,组胺与精胺,酪胺与精胺之间在0.01水平上具有显著相关性。     

不同发酵剂对羊肉发酵香肠中生物胺的影响

试验通过采用同种工艺生产3组发酵香肠,第1组为对照组(不添加任何发酵剂),第2组为市售发酵剂组,第3组为植物乳杆菌与肉葡萄球菌混合发酵剂组(3:1)。利用高效液相色谱仪(HPLC)分别测定了3组羊肉发酵香肠在发酵成熟过程中生物胺含量及种类的变化。结果表明:市售发酵剂和混合发酵剂对β-苯乙胺含量的抑制作用较小;在成熟末期时,混合发酵剂组尸胺的含量显著低于(P<0.01)市售发酵剂组,并且仅在成熟结束时检出市售发酵剂组胺含量为3.04 mg/kg,混合发酵剂组组胺未检出;在成熟结束时发酵剂组酪胺含量为22.54 mg/kg,对照组为132.67 mg/kg,市售发酵剂组酪胺含量为25.54 mg/kg,混合发酵剂组酪胺的含量显著(P<0.05)低于其他两组。     

处理发酵剂对促熟干酪中生物胺和游离氨基酸的影响

以0、30、60、90 d促熟干酪中生物胺（组胺、色胺、苯乙胺、尸胺、酪胺）和游离氨基酸含量为指标,研究了添加复合处理发酵剂对干酪产生游离氨基酸和生物胺量的影响。结果表明：不同处理发酵剂添加量对各种生物胺产生的影响不同;添加处理发酵剂干酪中生物胺和游离氨基酸含量增加,其含量随着复合处理发酵剂添加量增加而增加。     

Influence of pasteurised milk, raw milk and different ripening cultures on biogenic amine concentrations in semi-soft cheeses during ripening

In semi-soft cheeses, produced with pasteurised milk, raw milk and different starter cultures, the concentrations of cadaverine, histamine, phenylethylamine, putrescine and tyramine were investigated. The cultures (pasteurised milk cultures, raw milk cultures and starter cultures) strongly influenced the biogenic amine concentrations in the cheeses ripened for 5 months. Two cheeses made with identical pasteurised milk, but different ripening cultures, differed greatly in their total biogenic amine concentrations (51 vs 371?mg/kg). In general, the biogenic amine concentrations increased markedly between month 2 and month 3 of cheese ripening. The high content of enterococci and Enterobacteriaceae yielded the biogenic amine concentrations. In contrast, Lactobacilli did not seem to be important. However, unspecified bacteria have to be considered, since cheeses with comparable microbiological profiles differed enormously in their biogenic amine concentrations. Semi-soft cheeses produced from pasteurised milk showed remarkably lower total biogenic amine concentrations compared to semi-soft cheeses produced from raw milk (51–1096?mg/kg vs 1011–3133?mg/kg, depending also on the ripening cultures). The highest total biogenic amine concentration (4817?mg/kg) was detected in a cheese produced from raw milk that had been stored for 36?h. In this cheese, the concentrations of cadaverine, phenylethylamine, putrescine and tyramine were higher than in all other cheeses. The highest histamine concentration was found to be in another raw milk cheese (573?mg/kg).     

Detection of biogenic amine producer bacteria in a typical Italian goat cheese

The aim of this study was to research decarboxylating bacterial strains and biogenic amine content in a typical Italian goat cheese (Robiola di Roccaverano). The study was performed on fresh and ripened samples of goat cheese manufactured from industrial and artisanal producers. Sixty-seven bacterial strains isolated showed decarboxylating activity, and Enterococcus faecalis was the most widespread decarboxylating species in all artisanal and industrial products. Pediococcus acidilactici and Enterococcus malodoratus were also identified as biogenic amine producers in Robiola di Roccaverano cheese. All the E. faecalis strains isolated in this study were able to decarboxylate tyrosine. Tyramine was the most abundant biogenic amine in cheese samples, while histamine was the most widespread. High amounts of these two biogenic amines were found in ripened samples (up to 2,067 mg/kg for tyramine and 1,786 mg/kg for histamine), whereas 2-phenylethylamine and tryptamine were present in almost all ripened cheeses at low concentrations. The detection of strains producing biogenic amines and the high concentrations of tyramine and histamine found in ripened Robiola di Roccaverano could represent a potential risk to the consumer.     

Biogenic amines in Brazilian cheeses

The levels of biogenic amines in Brazilian cheeses were investigated for the first time. Ninety-two samples of 10 types of cheese were purchased at retail stores. The amines were extracted using hydrochloric acid, partitioned into diethyl ether, separated through reversed-phase ion-pair chromatography and quantified fluorimetrically after postcolumn derivatization with o-phthaldehyde. Overall, spermine was the most prevalent amine (93%), followed by histamine (65%), 2-phenylethylamine (62%), spermidine (61%), putrescine (60%), cadaverine (59%), serotonin (44%), agmatine (38%), tyramine (37%) and tryptamine (29%). Spermine, agmatine, 2-phenylethylamine, serotonin, spermidine and tryptamine were detected at low levels (< 4.10 mg/100g). Cadaverine, tyramine, histamine and putrescine were present at levels up to 111.00, 21.25, 19.65 and 17.37 mg/100g, respectively. There was variability on the type and levels of amine in each kind of cheese suggesting that amine formation and accumulation in cheese could be prevented. Efforts should be made to understand amine formation in cheese in order to optimize technology and secure low amine levels. Susceptible individuals should be advised to consume cheeses with low biogenic amines contents.     

Effect of added proteinases and level of starter culture on the formation of biogenic amines in raw milk Manchego cheese

The influence of two proteinases (Bacillus subtilis neutral proteinase and Micrococcus sp. cysteine proteinase) and two starter culture levels (0.1% and 1%) on biogenic amine formation has been studied in raw ewes' milk Manchego cheese. Amino acid decarboxylating micro-organisms were determined on tyrosine enriched selective media. Biogenic amines were analysed by capillary electrophoresis in citrate buffer at pH 3.6. Addition of proteinases and level of starter culture did not influence the population of micro-organisms with amino acid decarboxylating activity, which represented on average 1% of the bacterial population in 30-day-old cheeses. Tyramine and histamine were detected in all batches of cheese from day 30. Concentrations of tyramine and histamine were higher in cheeses made from milk with neutral proteinase (up to 356 and 284 mg kg(-1), respectively, after 90 days) than in cheeses made from milk with cysteine proteinase (up to 269 and 189 mg kg(-1), respectively) or with no proteinase added (up to 305 and 226 mg kg(-1), respectively). Formation of tyramine and histamine was also favoured in cheeses made with 1% starter culture with respect to cheeses made with only 0.1% starter culture, probably due to the higher pH values of the former cheeses. After 90 days of ripening, concentrations of 10-20 mg kg(-1) phenylethylamine were observed in 9 of the 12 batches, and levels < 10 mg kg(-1) tryptamine were only detected in 3 batches, with no significant relationship between the concentration of these amines and proteinase addition or level of starter culture.     

Biogenic amine formation and bacterial contribution in Natto products

Twenty-one Natto products currently distributed in Korea were analysed for biogenic amine contents and tested to determine physicochemical and bacterial contributions to biogenic amine formation. Among them, nine products (about 43%) had β-phenylethylamine or tyramine contents greater than the toxic dose (30mg/kg and 100mg/kg, respectively) of each amine, although no products showed total amounts of biogenic amines above the harmful level (1000mg/kg), which indicates that the amounts of biogenic amines in some Natto products are not within the safe level for human health. From four different Natto products, that contained noticeable levels of β-phenylethylamine and tyramine, 80 bacterial strains were isolated. All the strains were identified to be Bacillus subtilis and highly capable of producing β-phenylethylamine and tyramine. Therefore, it seems likely that the remarkable contents of β-phenylethylamine and tyramine in Natto predominantly resulted from the strains highly capable of producing those amines present in the food.     

四川区域自然发酵香肠及人工接种牦牛肉发酵香肠中生物胺含量的研究

以四川省10 区域自然发酵香肠及人工接种发酵剂的牦牛肉香肠共21 个样品为研究对象,测定发酵香肠中的生物胺含量。结果发现,21 个发酵香肠样品中均检测到酪胺、亚精胺、精胺、尸胺、腐胺、色胺及组胺,β-苯乙胺均未检出;生物胺总量在57.34～411.12 mg/kg,除采自凉山州西昌的自然发酵牦牛肉香肠和广安的自然发酵猪肉香肠中酪胺含量超过了美国食品及药品管理局（Food and Drug Administration,FDA）规定标准（酪胺含量≤100 mg/kg）,其余均不存在生物胺安全问题。     

Prerigor infusion of lamb with sodium chloride, phosphate, and dextrose solutions to improve tenderness

Various fermented and seasoned foods such as cheese, sauerkraut, wine, beer and meat products may contain biogenic amines. The aim of this paper was to describe the presence of some biogenic amines (histamine, tyramine, tryptamine, 2-phenylethylamine) in "Salamini italiani alla cacciatora PDO", a typical fermented-ripened dry sausage widely consumed in Italy. Total level of biogenic amines in commercial samples ranged from 71 to 586 mg kg(-1). The amine recovered in higher concentrations was tyramine (372 mg kg(-1)) followed by histamine (165 mg kg(-1)). The second aim of this work was the quality control of the production in order to determine the parameters influencing the presence of biogenic amines in ripened salami. Sausages sampled for analysis during production, manipulation and ripening showed the presence of tyramine (64.4 mg kg(-1)) only after 15 days of fermentation. All investigated biogenic amines were detected in "Salamini" after 21 days of fermentation. We suggest the control of biogenic as important tool to establish the better condition of preservation of "Salamini italiani alla cacciatore PDO" during their shelf-life.     

DETERMINATION OF pH CHANGE KINETICS DURING DIFFERENT STAGES OF KASHAR CHEESE MANUFACTURING FROM RAW AND PASTEURIZED MILK WITH ADDITION OF THERMOPHILIC, MESOPHILIC AND MIXED THERMOPHILIC CULTURE

The pH change kinetics during Kashar cheese production from raw and pasteurized milk with addition of thermophilic, mesophilic and mixed thermophilic-mesophilic lactic acid bacteria were evaluated. The kinetics of pH change were determined during milk ripening, cooking/holding and pressing/fermentation phases of Kashar cheese. The pH decreased logarithmically, nonlinearly, with time in the milk ripening period, and reduced linearly with time in the cooking/holding and pressing/fermentation stages. Pasteurization of milk retarded the rate of change in pH during the three periods. The highest rate of pH change was determined in the addition of thermophilic culture, followed by mixed thermophilic-mesophilic and then mesophilic ones during milk ripening. The pH change characteristics of cheese made with thermophilic starter were similar to the cheese made with mixed thermophilic-mesophilic culture, but different from mesophilic lactic acid bacteria during cooking/holding and pressing/fermentation stages.

PRACTICAL APPLICATIONS

One of the important factors in the control of cheese quality is the extent of acid production in the vat. Acid development at a desired rate is important during cheese making. The progress of acidification is monitored by pH change in the industrial Kashar cheese production. Three main stages have been recognized with respect to pH change: milk ripening, cooking/holding and pressing/fermentation. This study evaluated and compared the pH change kinetics during various stages of Kashar cheese making using raw, pasteurized milk with the addition of thermophilic, mesophilic and mixed thermophilic culture. This work may help in the comparison of raw and pasteurized milk, and in the selection of appropriate starter culture for Kashar cheese production.