Salmonella and Shigella in freshly squeezed orange juice, fresh oranges, and wiping cloths collected from public markets and street booths in Guadalajara, Mexico: incidence and comparison of analytical routes

A survey of the presence of Salmonella and Shigella in freshly squeezed orange juice and related samples was conducted in Guadalajara, Mexico. One hundred samples of freshly squeezed orange juice were collected from 49 street booths and 51 small food service establishments. In addition, 75 fresh orange samples, each consisting of five orange units, and 75 wiping cloths were collected from the same establishments from which juice had been collected. Salmonella was isolated from 14, 20, and 23% of samples of orange juice, orange surfaces, and wiping cloths collected from street vendors, while Shigella was isolated from 6, 17, and 5% of these samples. In general, the frequency of isolation of these pathogens in samples from juice serving establishments at public markets was significantly lower than that found among street vendors (P < 0.05). Salmonella enterica serotypes Agona, Typhimurium, and Anatum were found in orange juice, fresh oranges, and wiping cloth samples, while serotype Mexico was found on fresh oranges and in wiping cloths and serotypes Muenchen and Panama were found only in wiping cloth samples. Regarding Shigella species, Shigella sonnei was found in all three types of sample tested; Shigella dysenteriae was found in juice and orange samples, Shigella boydii in orange and wiping cloth samples, and Shigella flexneri on oranges only. Thirty-one percent and 39% of the juice samples showed aerobic plate counts of > or = 5.0 log CFU/ml and Escherichia coli counts of > 3.0 log CFU/ml, respectively. These high counts may indicate poor sanitation and potential exposure to fecal contamination either in the raw materials or during the orange-crushing and juice-serving process. These data may be useful for a further risk assessment of Salmonella or Shigella in unpasteurized, freshly squeezed juice.     

Characterization and classification of Thymus capitatus (L.) honey according to geographical origin based on volatile compounds,physicochemical parameters and chemometrics

Greek thyme honeys (Thymus capitatus L.) were characterized and classified according to geographical origin based on the determination of volatile compounds and physicochemical parameters using MANOVA and Linear Discriminant Analysis. Forty two thyme honey samples were collected during the harvesting period in 2011 from 5 different regions in Greece known to produce thyme honey of good quality. The analysis of volatile compounds was performed by Headspace Solid Phase Microextraction coupled to Gas chromatography/Mass spectroscopy. Forty seven volatile compounds were identified and semi-quantified. Physicochemical analysis included the determination of pH, free, lactonic and total acidity, electrical conductivity, moisture, ash, lactonic/free acidity ratio and color parameters: L*, a*, b*. Using 9 volatile compounds and 11 physicochemical parameters the honey samples were satisfactorily classified according to geographical origin using volatile compounds (64.3% correct prediction), physicochemical parameters (92.7% correct prediction), and the combination of both (92.9% correct prediction).     

“南山荔枝”糯米糍外观、味感的特色因子

采集了地理标志保护产品深圳"南山荔枝"糯米糍样品,对其22项外观、味感指标进行分析,同时与惠阳、增城两地同一品系的非地理标志保护糯米糍进行比较。3个产地糯米糍荔枝蔗糖含量均占总糖的50%以上,是构成糯米糍荔枝甜味的主要因素;有机酸主要为酒石酸和苹果酸,是构成酸味的主要因素。通过主成分分析法对3个产地荔枝样品进行分类,3个产地的样品得到合理分类,其中单果质量、果肉质量、果汁质量、果皮厚度、还原糖、总糖、酒石酸等7个指标是决定样品分类的关键因素,也是地理标志保护产品"南山荔枝"糯米糍外观与味感的特色因子。     

工业用浓缩橙汁生产与市场前景

<正> 果蔬汁在世界各地是非常流行的健康饮料,特别是橙汁和苹果汁,极具市场潜力。生产优质的果汁,必须做到从水果的种植到提炼加工及处理各方面的管理控制得宜。 提炼工艺与重点 浓缩果汁作为一种原材料供食品或饮料商作产品的开发,它的品质必须要有所保证。而生产优质的浓缩果汁首要的条件是水果的品质,因此水果的来源是很重     

中国甜橙果汁色泽的定量评价

色泽是甜橙及其橙汁的一项重要的感官指标,直接影响到消费者的选择。本研究采用国际公认的色差法定量测定我国主要甜橙产区目前栽培的具有代表性的94 个甜橙样品果汁的色泽参数,建立了我国橙汁色泽特征数据库。统计结果表明：我国的甜橙果汁的色泽普遍高于36,优于美国和巴西的同类品种;不同品种、不同产区甜橙果汁色泽差异显著,但不同年度采收的甜橙果汁色泽差异不显著(P ＞ 0.05)。     

Investigating the impact of botanical origin and harvesting period on carbon stable isotope ratio values (13C/12C) and different parameter analysis of Greek unifloral honeys: A chemometric approach for correct botanical discrimination

The aim of this study was to investigate the impact of botanical origin and harvesting period on carbon stable isotope ratio (¹³C/¹²C), colour intensity (CI), radical scavenging activity (%RSA), P and Sn content of Greek unifloral honeys. Thus, twenty‐four honey samples were collected during harvesting periods 2011–2012 and 2012–2013, from four different regions in Greece. ¹³C/¹²C ratios and minerals were determined using isotope ratio mass spectrometry (IRMS) and inductively coupled plasma optical–emission spectroscopy (ICP‐OES), respectively. CI and %RSA were measured using spectrophotometric assays. Results showed that only ¹³C/¹²C values and %RSA were affected by both botanical origin and harvesting period (P < 0.05). Applying then chemometric analyses to the collected data set, honeys were correctly classified according to honey type (correct classification rate 87.5% and 79.2% using the original and cross‐validation method, respectively). The use of different origin parameters has the potential to aid in honey authentication.     

Spread of bacterial pathogens during preparation of freshly squeezed orange juice

To study the potential of three bacterial pathogens to cross-contaminate orange juice during extraction, normal operation conditions during juice preparation at food service establishments were simulated. The spread of Salmonella enterica serovar Typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes from inoculated oranges to work surfaces and to the final product was determined. The transference of these three bacterial pathogens to orange juice made from uninoculated oranges with the use of contaminated utensils was also studied. Fresh oranges were inoculated with a marker strain of rifampicin-resistant Salmonella Typhimurium, E. coli O157:H7, or L. monocytogenes. Final pathogen levels in juice were compared as a function of the use of electric or mechanical juice extractors to squeeze orange juice from inoculated oranges. Pathogen populations on different contact surfaces during orange juice extraction were determined on sulfite-phenol red-rifampicin plates for Salmonella Typhimurium and E. coli O157:H7 and on tryptic soy agar supplemented with 0.1 g of rifampicin per liter for L. monocytogenes. After inoculation, the average pathogen counts for the orange rind surface were 2.3 log10 CFU/cm2 for Salmonella Typhimurium, 3.6 log10 CFU/cm2 for E. coli O157:H7, and 4.4 log10 CFU/cm2 for L. monocytogenes. This contamination was spread over all utensils used in orange juice squeezing. Mean pathogen counts for the cutting board, the knife, and the extractor ranged from -0.3 to 2.1 log10 CFU/cm2, and the juice contained 1.0 log10 CFU of Salmonella Typhimurium per ml, 2.3 log10 CFU of E. coli O157:H7 per ml, and 2.7 log10 CFU of L. monocytogenes per ml. Contact with contaminated surfaces resulted in the presence of all pathogens in orange juice made from uninoculated oranges. These results give emphasis to the importance of fresh oranges as a source of pathogens in orange juice.     

Determination of volatile, phenolic, organic acid and sugar components in a Turkish cv. Dortyol (Citrus sinensis L. Osbeck) orange juice

BACKGROUND: Orange flavour is the results of a natural combination of volatile compounds in a well‐balanced system including sugars, acids and phenolic compounds. This paper reports the results of the first determination of aroma, organic acids, sugars, and phenolic components in Dortyol yerli orange juices. RESULTS: A total of 58 volatile components, including esters (nine), terpenes (19), terpenols (13), aldehydes (two), ketones (three), alcohols (four) and acids (eight) were identified and quantified in Dortyol yerli orange juice by GC‐FID and GC‐MS. Organic acids, sugars and phenolic compositions were also determined by HPLC methods. The major organic acid and sugar found were citric acid and sucrose, respectively. With regard to phenolics, 14 compounds were identified and quantified in the orange juice. CONCLUSION: Terpenes and terpenols were found as the main types of volatile components in Dortyol yerli orange juice. In terms of aroma contribution to orange juice, 12 compounds were prominent based on the odour activity values (OAVs). The highest OAV values were recorded for ethyl butanoate, nootkatone, linalool and DL ‐limonene. When we compare the obtained results of cv. Dortyol orange juice with the other orange juice varieties, the composition of Dortyol orange juice was similar to Valencia and Navel orange juices. Copyright © 2011 Society of Chemical Industry     

Fertilisation and pesticides affect mandarin orange nutrient composition

The effects of the application of foliar fertilisation and pesticide on nutritional quality of mandarin orange juices were evaluated using ¹H NMR metabolomics. Significant differences between the use of fertiliser and pesticides during fruit formation were observed, and included changes in sugar, amino acid and organic acid composition. To determine whether the difference in sugar concentration was enough for the consumer to detect, a sensory experiment was performed in which two orange juice samples were prepared to resemble the sweet/sour taste balance of juice from mandarin oranges in which foliar fertilisation was either applied or not. In a test using non-trained individuals, 68% could correctly identify which juice had a sourer, or less sweet, taste. The implications of this study could impact citrus growers, and ultimately aid in development of fruit with superior sensory quality.     

The potential of NIR spectroscopy for the detection of the adulteration of orange juice

Near-infrared spectroscopy was used to investigate the adulteration of 65 authentic concentrated orange juice samples obtained from Brazil and Israel. These samples were adulterated with 100 g kg^?1 additions (ie 100 g added to 900 g) of (1) orange pulpwash, (2) grapefruit juice, and (3) a synthetic sugar/acid mixture and with 50 g kg^?1 additions (ie 50 g added to 950 g) of (4) orange pulpwash, and (5) grapefruit juice. All samples were scanned on the NIR systems 6500 spectrophotometer over the 1100-2498 nm wavelength range. Principal component analysis was used to reduce each spectrum to 20 principal components. Factorial discriminant analysis was used to distinguish between the different sample groups. Using orange juice and orange juice adulterated at the 100 g kg^?1 level, accurate classification rates of 94–95% were obtained. To classify samples adulterated at the 50 g kg^?1 level, the calibration development sample set had to be augmented by the inclusion of samples adulterated at this lower level—after this augmentation, an accurate classification rate of 94% was obtained. The results demonstrated that the application of principal component and factorial discriminate analysis to NIR reflectance spectra can detect the adulteration of orange juice with an average accuracy of 90%. Furthermore, not one adulterated sample was predicted as being an authentic orange juice throughout the entire test regime.     

基于电子舌检测的橙汁贮藏品质研究

为实现对不同储存时间的鲜榨橙汁品质进行客观、快速的评价,采用基于虚拟仪器技术的电子舌系统对6种不同储存时间下的鲜榨橙汁样本进行定性和定量分析。针对电子舌输出信号特点,分别采用主成分分析(Principal Component Analysis,PCA)和离散小波变换(Discrete Wavelet Transform,DWT)方法对输出信号进行预处理,以分类效果为依据,确定离散小波变换作为较佳特征提取方法。在此基础上,采用线性判别分析(Linear Discriminant Analysis,LDA)方法对不同储存时间鲜榨橙汁样本进行定性分析,然后采用粒子群优化最小二乘支持向量机(Particle Swarm Optimization Least Squared-Support Vector Machines,PSOLSSVM)对鲜榨橙汁的不同储存时间进行定量预测。结果表明:LDA结果中第一判别式(LD1)和第二判别式(LD2)的综合贡献率为95.7%,6种储存时间下的鲜榨橙汁样本均得到有效定性辨别;而PSO-LSSVM预测模型对鲜榨橙汁的不同储存时间具有较高的定量预测精度,其相关系数(R~2)、均方根误差、平均绝对误差分别为0.999 1,0.287 7,0.232 8。     

鲜牛乳橙汁复合饮料研发的响应面设计优化

以夏橙果汁和鲜牛乳为主要原料,采用Design-Expert7.0软件,通过单因素试验和Box-Behnken的中心组合试验设计以及响应面分析,对复合稳定剂配比以及鲜牛乳橙汁复合饮料原料配比进行优化研究。结果表明：复合稳定剂配比为：CMC-Na0.23%、海藻酸钠0.15%、果胶0.07%,此时复合饮料的离心率为2.86%,稳定性较优;原料配比为：鲜牛乳24.76%、橙汁21.06%、白砂糖5.22%、柠檬酸0.10%,在此配比方案下鲜牛乳橙汁复合饮料感官评分值为86.63分,可制作出质量和风味俱佳的鲜牛乳橙汁复合饮料。     

Factors influencing quantities of sugars and organic acids in blackcurrant concentrates

 Use of endogenous non-volatile flavour components, i. e. sugars and organic acids, in fruit juice products is desirable. A study of 133 blackcurrant concentrates from three seasons examined variation in sugars and acids arising from storage of fruit at freezing or sub-ambient temperature, seasonal differences, geographical origin and choice of conventional thermal-evaporative or freeze concentration technology. Compared with freeze concentrates, conventional concentrates had significantly higher contents of total sugars and acids, notably malic acid, and higher fructose/glucose, lower malic/citric acid and similar sugar/acid ratios. Concentrates from frozen fruit generally had smaller amounts of fructose, total sugars and fructose/glucose ratios than those from fresh fruit, as well as less citric, ascorbic and total acids and lower sugar/acid ratios. Principal component analysis of 40 randomly chosen concentrates showed that variance is dominated by differences in fructose, total sugars and ascorbic acid contents and sugar/acid ratios. Geographical origin and concentration technology were major sources of variance but changes in post-production sub-ambient storage could not be excluded. Received: 4 July 1997 /  Revised version: 14 October 1997     

草莓汁中糖酸组成分析及其在掺假鉴别中的应用

为了解草莓汁的糖酸组成特点并探索其在掺假鉴别中的应用,采用高效液相色谱法对10个品种草莓果汁中可溶性糖、有机酸组成与含量进行分析,结合化学计量学方法探索其在草莓汁掺假鉴别中的应用。结果表明,草莓汁中可溶性糖主要由蔗糖、葡萄糖和果糖组成,有机酸主要是柠檬酸和苹果酸。不同品种草莓果汁中各种可溶性糖和有机酸的含量存在较大差异,但葡萄糖与果糖的比值受品种影响较小,柠檬酸占检测到总有机酸含量的62.39%~82.73%。通过分析草莓原汁及其掺假样品中可溶性糖和有机酸组成,结合主成分分析和线性辨别分析等模式识别方法,可以实现对草莓果汁与掺加梨汁、苹果汁、杏汁和桃汁等掺假样品的区分,而且掺假量越大,区分效果越好。草莓果汁可溶性糖和有机酸组成特征结合化学计量学分析能够对掺假草莓果汁进行较好地区分,可用于草莓果汁掺假鉴定和质量控制。     

Potential for internalization, growth, and survival of Salmonella and Escherichia coli O157:H7 in oranges

Internalization potential, survival, and growth of human pathogens within oranges were investigated in a series of laboratory experiments. Submerging oranges into dye solutions at various temperature differentials was used to assess internalization potential. Conditions in which dye internalization was observed were further studied by applying Escherichia coli O157:H7 or Salmonella onto the stem scar, subjecting the oranges to a temperature differential, juicing, and measuring numbers of pathogens in the resulting juice. Pathogens for growth and survival studies were applied to or injected into simulated peel punctures. Oranges with small peel holes of selected sizes were also placed into solutions containing these pathogens. Bacterial survival was also evaluated in orange juice at 4 and 24 degrees C. Oranges internalized pathogens at a frequency of 2.5 to 3.0%, which mirrored dye internalization frequency (3.3%). Pathogens were internalized at an uptake level of 0.1 to 0.01% of the challenge applied. Bacteria grew within oranges at 24 degrees C, but not at 4 degrees C. Thirty-one percent of oranges with 0.91-mm surface holes showed pathogen uptake, whereas 2% of oranges with 0.68-mm holes showed pathogen uptake. Pathogens added to fresh orange juice and incubated at 24 degrees C declined 1 log CFU/ml within 3 days. These results suggest that internalization, survival, and growth of human bacterial pathogens can occur within oranges intended for producing unpasteurized juice.     

Elemental content and nutritional study of blood orange juice

BACKGROUND: The elemental content of Sicilian red orange juices and the bioaccessibility of many elements of particular nutritional interest was evaluated. RESULTS: The elemental content of fresh juices from Sicilian blood oranges was analysed by ICP–OES, GF AAS, HG–AAS and CV AAS. Among the macroelements (Na, Ca, K, Mg and P), potassium occurred in the greatest amount, with 3.64% of the requested RDA for 100 mL of juice daily intake. The values of RDA 100 mL^?1 of juice for Mg, P, Ca and Na resulted 1.61%, 1.26%, 0.59% and 0.09% respectively. For the trace elements Cr, Cu and Se, the RDA 100 mL^?1 of juice were 9.20%, 7.14% and 1.82%, respectively. In vitro tests simulating the digestive process showed high bioaccessibility only for boron and manganese while that of copper, zinc and iron were consistently lower. CONCLUSIONS: Sicilian blood orange juices gave different results from non‐pigmented orange juices in terms of a higher content of copper, boron and lower content of chromium and manganese. However, among the nutritionally important elements, only manganese showed high bioaccessibility. The low bioaccessibility found for iron, zinc and copper is likely due to the presence in the orange juice of ligands such as polyphenols and organic acids. Copyright © 2009 Society of Chemical Industry     

Floral authentication of Greek unifloral honeys based on the combination of phenolic compounds,physicochemical parameters and chemometrics

Greek unifloral honeys (pine, thyme, fir, orange blossom) were characterized and classified according to botanical origin based on phenolic compound content and conventional physicochemical parameters using MANOVA and Linear Discriminant Analysis. One hundred and nineteen honey samples were collected during the harvesting period 2011 from 14 different regions in Greece known to produce unifloral honey of good quality. The analysis of phenolic compounds quercetin (3,5,7,3′,4′-pentahydroxyflavone), myricetin (3,5,7,3′,4′,5′-hexahydroxyflavone), kaempferol (3,5,7,4′-tetrahydroxyflavone), chrysin (5,7-dihydroxyflavanone), and syringic acid (4-hydroxy-3,5-dimethoxybenzoic acid), was performed by high pressure liquid chromatography. Conventional quality parameter analysis included the determination of: pH, free, lactonic and total acidity, electrical conductivity, moisture, ash, as well as lactonic/free acidity ratio and colour parameters L*, a*, and b*. Using 4 phenolic compounds and 10 conventional quality parameters honey samples were satisfactorily classified (96.6% correct prediction) according to botanical origin.     

脐橙全果酒发酵工艺优化及其与脐橙果汁酒风味物质的对比分析

以脐橙全果为原料酿造脐橙全果酒,采用单因素试验和Box-Behnken试验设计,分析酵母接种量、发酵温度、发酵时间对脐橙全果酒发酵的影响。结果表明其最佳条件为：酵母接种量6.4%、发酵温度28 ℃、发酵14d。同时,采用顶空固相微萃取法、利用气相色谱-质谱联用技术对脐橙全果酒和脐橙果汁酒风味物质进行分析。结果表明：在脐橙全果酒和脐橙果汁酒中分别检出25 种和11 种挥发性香气物质,且脐橙全果酒的香气活性成分主要为萜烯类,占香气成分的66.00%,而脐橙果汁酒的主要香气成分为醇类,所占比例为91.95%。     

Differentiation of Greek Thyme Honeys According to Geographical Origin Based on the Combination of Phenolic Compounds and Conventional Quality Parameters Using Chemometrics

The aim of the present study was to differentiate Greek thyme honeys according to geographical origin, based on phenolic compound content and conventional physicochemical parameters using MANOVA and Linear Discriminant Analysis. Thirty-five thyme honey samples were collected during the harvesting period 2011 from four different regions in Greece (Irakleio, Hania, Kefalonia and Lakonia) known to produce thyme honey of good quality. The analysis of phenolic compounds (quercetin, myricetin, kaempferol, chrysin, and syringic acid) was performed by high pressure liquid chromatography. Conventional quality parameter analysis included the determination of the following: pH, free, lactonic and total acidity, electrical conductivity, moisture, ash, as well as lactonic/free acidity ratio and colour parameters L*, a*, b*. Using five phenolic compounds and 11 conventional quality parameters, thyme honey samples were satisfactorily classified (91.2 % correct prediction) according to geographical origin.     

广东清新冰糖桔与郁南无核沙糖桔特性差异研究

采集了具有地理标志产品保护标志的广东清新冰糖桔与郁南无核砂糖桔共2700个果实,通过感官、理化分析和高效液相色谱法对14个常见理化指标进行分析。采用了变异系数分析、相关分析法对14个指标进行研究,结果表明所选的各项指标具有较好的代表性。通过主成分分析法与聚类分析法进行分类,两个产地的样品得到合理分类。砂糖桔果实的单果重、横径、总糖含量是决定产地分类的关键因素,主成分分析法是对砂糖桔产地分类的有效方法。