Practical Experience with 'Electronic Nose' Systems for Monitoring the Quality of Dairy Products

The present paper reports some practical experience acquired by testing five sensor technologies and four instruments over approximately one year with Swiss Emmental cheese samples of different stage of ripening. Up to now, the metal-oxide semiconductor (MOS) technology has given the best discrimination between the measured samples. However, sensors of this type seem to be damaged by short-chain fatty acids released from Swiss Emmental cheese. Organic conducting polymer sensors showed a poor sensitivity to volatile components of cheese, the main problem being a rapid drift of the sensors. The response of quartz microbalance sensors was too weak to detect differences between cheese samples. Discrimination using a newly designed mass-spectrometry system was difficult due to the low sensitivity of this instrument for the volatile compounds of cheese. Metal-oxide semiconductor field effect transistor sensors did not give good discrimination between the samples. However, their combination with MOS sensors seems to produce a favourable system for application in cheese evaluation. Further studies with other types of cheese and other dairy products are still necessary to define reliable and practical applications of this analytical tool in the dairy industry

Atherosclerosis Screening by Noninvasive Imaging for Cardiovascular Prevention: A Systematic Review

ABSTRACT: BACKGROUND: Noninvasive imaging of atherosclerosis is being increasingly used in clinical practice, with some experts recommending to screen all healthy adults for atherosclerosis and some jurisdictions mandating insurance coverage for atherosclerosis screening. Data on the impact of such screening have not been systematically synthesized. OBJECTIVES: We aimed to assess whether atherosclerosis screening improves cardiovascular risk factors (CVRF) and clinical outcomes. DESIGN: This study is a systematic review. DATA SOURCES: We searched MEDLINE and the Cochrane Clinical Trial Register without language restrictions. STUDY ELIGIBILITY CRITERIA: We included studies examining the impact of atherosclerosis screening with noninvasive imaging (e.g., carotid ultrasound, coronary calcification) on CVRF, cardiovascular events, or mortality in adults without cardiovascular disease. RESULTS: We identified four randomized controlled trials (RCT, n = 709) and eight non-randomized studies comparing participants with evidence of atherosclerosis on screening to those without (n = 2,994). In RCTs, atherosclerosis screening did not improve CVRF, but smoking cessation rates increased (18% vs. 6%, p = 0.03) in one RCT. Non-randomized studies found improvements in several intermediate outcomes, such as increased motivation to change lifestyle and increased perception of cardiovascular risk. However, such data were conflicting and limited by the lack of a randomized control group. No studies examined the impact of screening on cardiovascular events or mortality. Heterogeneity in screening methods and studied outcomes did not permit pooling of results. CONCLUSION: Available evidence about atherosclerosis screening is limited, with mixed results on CVRF control, increased smoking cessation in one RCT, and no data on cardiovascular events. Such screening should be validated by large clinical trials before widespread us

Element signature analysis: its validation as a tool for geographic authentication of the origin of dried beef and poultry meat

Element concentrations of 56 poultry meat and 53 dried beef samples were determined and statistically analyzed using analysis of variance and linear discriminant analysis (LDA) to identify the single or combination of elements with the highest potential to determine the geographic origin. In order to validate the applicability of this technique, the results were additionally combined with data from an earlier assessment including 25 poultry meat and 23 dried beef samples. Validation was performed by estimating the origin of the first samples based on the data of the second, larger, dataset. Elements significantly discriminating among countries were As, Na, Rb, Se, Sr, and Tl for poultry meat and As, B, Ba, Ca, Cd, Cu, Dy, Er, Fe, Li, Mn, Pd, Rb, Se, Sr, Te, Tl, U, and V for dried beef out of about 50 elements each. The LDA gave mean correct classification rates of 77 and 79% for poultry meat and dried beef, respectively. Validation allowed identifying some, but not all, origins. For a higher discriminative power, this method should be combined with other ways of authenticatio

Quantitative analysis of physical and chemical measurands in honey by mid-infrared spectrometry

Fourier transform infrared spectroscopy (FT-IR) was used to determine 20 different measurands in honey. The reference values for 144 honey samples of different botanical origin were determined by classical physical and chemical methods. Partial least squares regression was used to develop the calibration models for the measurands studied. They were validated using independent samples and proved satisfying accuracies for the determination of water (R 2=0.99), glucose (0.94), fructose (0.84), sucrose (0.91), melezitose (0.98) and monosaccharide content (0.82) as well as fructose/glucose ratio (0.98), glucose/water ratio (0.94), electrical conductivity (0.98), pH-value (0.87) and free acidity (0.96). The prediction accuracy for hydroxymethylfurfural, proline and the minor sugars maltose, turanose, erlose, trehalose, isomaltose and kojibiose was rather poor. The results demonstrate that mid-infrared spectrometry is a valuable, rapid and non-destructive tool for the quantitative analysis of the most important measurands in hone

Application de méthodes d'analyse statistique univariée et multivariée à l'étude parallèle de critères chimiques, biochimiques, rhéologiques, microbiologiques et sensoriels du fromage d'emmental au moment de sa taxation Partie I: Analyse de quelques profils de distribution

This multidisciplinary study of Swiss Emmental cheese relates values determined by chemical, biochemical, rheological, and bacteriological analyses to those obtained by sensoric analysis of taste as well as tactile and visual properties. To this effect, 50 four-months-old Emmental loaves of different qualities were chosen at their taxation and submitted to 165 analyses; six of these analyses were sensoric evaluations. The instrumental analyses included quantitative determination of water, fat, salt, volatile fatty acids, lactic acid (L and D), nitrogen fractions (TN, WSN, NPN), ammonia, free amino acids, biogenic amines, one peptide, and volatile components. The latter were analyzed with two different methods. Moreover, two microbiological analyses were carried out (non-lactic-acid bacteria and streptococci of group D), four rheological measurements (penetration depth, stress at 33% deformation, compression rate and stress at peak stress point) and determination of three colour components according to Hunter. The sensoric taste analysis permitted us to evaluate the flavour development, the typical character and the quality of the cheese. The tactile analysis enabled us to characterize the texture, structure, and consistency and the visual evaluation to examine the eyes of the cheese body. The first part of this paper divided into 3 parts deals with univariate analysis of distribution profiles of some characteristic measurable variables for Swiss Emmental cheese

Indications for the applicability of element signature analysis for the determination of the geographic origin of dried beef and poultry meat

In order to determine the geographic origin of poultry and dried beef, concentrations of a total of 72 different elements (occasionally represented with several isotopes) were analyzed by inductively coupled plasma high resolution mass spectrometry (ICP-HRMS). Additionally, gross chemical composition (GCC) was analyzed. The 25 poultry breast filets samples originated from Switzerland, France, Germany, Hungary, Brazil, and Thailand, and the 23 dried beef samples, made from M. biceps femoris and M. semitendinosus, were produced in Switzerland, Austria, Australia, United States, and Canada out of raw meat originating either from these or from other countries. A total of 66 and 46 of the elements and isotopes followed were detected in beef and poultry, respectively. For statistical analyses, only the most abundant isotopes per element were used. For both poultry meat and dried beef, a differentiation of the origins was possible using those elements, which were significantly different across countries (As, Na, Rb, and Tl in poultry; B, Ca, Cd, Cu, Dy, Eu, Ga, Li, Ni, Pd, Rb, Sr, Te, Tl, Tm, V, Yb, and Zn in beef). No sufficient differentiation between origins was possible with GCC. Further studies have to confirm the suitability of this approach for meat authentication with more sample

Quantitative determination of physical and chemical measurands in honey by near-infrared spectrometry

Fourier transform near-infrared spectroscopy (FT-NIR) was evaluated to quantitatively determine 24 different measurands in honey. The reference values of 421 honey samples of different botanical origins were determined by classical physical and chemical methods. Partial least squares regression was used to develop the calibration models for the measurands studied. These calibrations were then validated using independent samples and proved satisfying accuracies for the determination of water (standard error of prediction: 0.3g/100g), glucose (1.3g/100g), fructose (1.6g/100g), sucrose (0.4g/100g), total monosaccharide content (2.6g/100g) as well as fructose/glucose ratio (0.09) and glucose/water ratio (0.12). The prediction accuracy for hydroxymethylfurfural, proline, pH-value, electrical conductivity, free acidity and the minor sugars maltose, turanose, nigerose, erlose, trehalose, isomaltose, kojibiose, melezitose, raffinose, gentiobiose, melibiose, maltotriose was poor and unreliable. The results demonstrate that near-infrared spectrometry is a valuable, rapid and non-destructive tool for the quantitative analysis of some measurands related to the main components in hone

Authentication of the botanical origin of honey using profiles of classical measurands and discriminant analysis

The potential of physical and chemical measurands for the determination of the botanical origin of honey by using both the classical profiling approach and chemometrics was evaluated for the authentication of ten unifloral (acacia, rhododendron, chestnut, dandelion, heather, lime, rape, fir honeydew, metcalfa honeydew) and polyfloral honey types (in total n = 693 samples). The classical approach using a profile for the determination of the botanical origin of honey revealed that the physical and chemical measurands alone do not allow a reliable determination. Pollen analysis is therefore essential for discrimination between unifloral and polyfloral honeys. However, chemometric evaluation of the physical and chemical data by linear discriminant analysis allowed reliable authentication with neither specialized expertise nor pollen or sensory analysis. The error rates calculated by Bayes' theorem ranged from 1.1% (rape and lime honeys) up to 9.9 % (acacia honey

Tracing the geographic origin of poultry meat and dried beef with oxygen and strontium isotope ratios

Two promising isotope ratios, the δ18O of the water fraction, as extracted by azeotropic distillation, and the 87Sr/86Sr of the ash fraction were tested for their applicability to determine the geographic origin. In two sampling phases, in total 78 fresh poultry breast meat and 72 dried beef samples, independent from each other and originating from different countries, were analysed. The δ18O was measured with isotope ratio mass spectrometry and the isotope abundance ratio of 87Sr/86Sr with a multicollector inductively coupled plasma mass spectrometer. With δ18O it was possible to distinguish (p<0.001) poultry and dried beef samples according to their country of origin. The beef data suggests that the procedure of processing is of only low additional influence on δ18O and, if so, it seems to reduce the initial between-country differences. The 87Sr/86Sr ratio did not give sufficient indications for differentiation by geographic origin in either poultry meat or dried beef in the smaller, first phase, data set and was therefore not further teste

Trastuzumab Mediated T-Cell Response against HER-2/Neu Overexpressing Esophageal Adenocarcinoma Depends on Intact Antigen Processing Machinery

BACKGROUND: Esophageal adenocarcinoma (EAC) is a highly aggressive disease with poor prognosis, which frequently exhibits HER-2 gene amplification. Trastuzumab, the humanized antibody against HER-2, has potent growth inhibitory effects on HER-2 overexpressing cancers. One effect of trastuzumab is that it causes HER-2 receptor internalization and degradation, enhancing presentation of HER-2 epitopes on MHC-Class I molecules. This enhances the ability of HER-2 specific cytotoxic T lymphocytes (CTLs) to recognize and kill cancer cells. Novel strategies targeting the HER-2 receptor either directly by trastuzumab and/or indirectly by inducing a CTL response against HER-2 epitopes with, for instance, DC immunotherapy and consequently combining these strategies might prove to be very effective. METHODOLOGY/PRINCIPAL FINDINGS: In this study we report that trastuzumab has potent growth inhibitory effects on two HER-2 overexpressing EAC cell lines OE33 and OE19. However, we found that trastuzumab and HER-2 specific CTLs act synergistically in inducing tumor lysis in OE33 but not in OE19. We discovered that in OE19 this deficient response is due to a down-regulation of the Transporter Associated with Antigen Processing-2 (TAP-2). TAP-2 is an important member of the Antigen Processing Machinery (APM), and is one of the essential elements for loading antigens on MHC class I molecules. Importantly, we demonstrated that by inducing re-expression of TAP-2 in OE19 with INF-γ treatment or by incubating the cells with INF-γ producing CTLs, the specific anti HER-2 CTL tumor lysis response and synergistic effect with trastuzumab can be restored. CONCLUSION: An inefficient response of HER-2 overexpressing EAC to trastuzumab and/or DC immunotherapy can be due to a down-regulated TAP-2 expression and thus a deficient APM. Future studies combining trastuzumab with IFN-γ and/or immune-therapies inducing potent anti HER-2 CTL responses could lead to an effective combinatorial strategy for successful treatment of HER-2 overexpressing but APM defective cancer