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The aim of this study was to determine the role of the precursors cadaverine and piperidine in the N-nitrosopiperidine (NPIP) formation during the production of dry fermented sausages. The influences of pH (4.9 and 5.3), sodium nitrite (0 and 150 mg/kg) and ascorbate (0 and 500 mg/kg) were investigated by the use of a dry fermented sausage model. The biogenic amines and volatile N-nitrosamines were analyzed by HPLC-UV and GC-TEA. The major biogenic amines were tyramine (TYR), putrescine (PUT) and cadaverine (CAD), but their accumulation could be inhibited by NaNO2. When no amine precursors were added, no meaningful N-nitrosamine contamination was observed. The artificial addition of 500 mg/kg cadaverine dihydrochloride (CAD.2HCl) could not provoke an increased N-nitrosamine formation. In contrast, the addition of PIP (10 and 100 mg/kg) resulted in higher NPIP concentrations. No influence of pH was observed but the NPIP formation was more pronounced when NaNO2 was added and sodium ascorbate was excluded from the formulation. The role of ascorbate as N-nitrosamine scavenger was only detectable during the early stage of the production. In the end products, NPIP was degraded and the levels were no longer influenced by the initial addition of NaNO2 or ascorbate. ispartof: Food and Bioprocess Technology vol:7 issue:5 pages:1269-1280 status: published

A survey at five pigs' slaughterhouses was performed to investigate the effect of a quality assurance system, pre-slaughter conditions and slaughterhouse facilities on pork quality. Totally, 2246 pigs were included over four transports per slaughterhouse, i.e. two transports were produced according to a quality assurance system and the other two were conventional pigs. Meat quality was measured on 446 pigs. The pH in the longissimus dorsi muscle and the electrical conductivity in the semimembranosus muscle were measured 30min post-mortem. Twenty-four hours later pH and electrical conductivity in both the longissimus dorsi and the semimembranosus muscle were measured. Pigs managed according to a chain quality protocol showed an overall higher potential for improved meat quality. Differences in meat quality between the different slaughterhouses were also found, however they were dependent on muscle type and time of measuring. Influencing factors on pork quality seemed to be stocking density during transport, the handling during offloading the pigs from the truck, stocking density, and air temperature during lairage.

The commonly applied HPLC method to determine biogenic amines in dry fermented meat after dansylation was compared with an alternative dabsylation procedure. The use of dabsyl chloride at 70 C resulted in a 25-min reduction of the derivatisation time, in comparison with the dansylation at 40 C. Furthermore, the use of irritating ammonia to remove the excess of dansyl chloride can be avoided. Introduction of the SPE cleaning procedure on the C18 cartridge resulted in a reliable and sensitive method of biogenic amines determination in a complex protein–fat matrix, which is typical of dry fermented sausages. The biogenic amines tryptamine (TRYP), phenethylamine (PHE), putrescine (PUT), cadaverine (CAD), histamine (HIS), serotonin (SER), tyramine (TYR), and the natural polyamines spermidine (SPD) and spermine (SPM), were separated by means of gradient HPLC, using the two coupled C18 Chromolith reversed phase column. ispartof: Food Chemistry vol:130 issue:4 pages:1017-1023 status: published

The influence of biogenic amines (i.e. putrescine, cadaverine, spermidine and spermine) on the N-nitrosamine formation in heated cured lean meat was studied in the presence or absence of sodium nitrite and at different meat processing temperatures. Experimental evidence was produced using gas chromatography with thermal energy analysis detection (GC-TEA). Concentration of N-nitrosamines was modelled as a function of the temperature and the nitrite concentration for two situations, i.e. presence or absence of added biogenic amines to the meat. The significance of the influence of the changing parameters was evaluated by ANOVA (Analysis of Variance). It was found that higher processing temperatures and higher added amounts of sodium nitrite increase the yields of N-nitrosodimethylamine (NDMA) and N-nitrosopiperidine (NPIP). Spermidine and putrescine amplify the formation of NDMA, but spermine and cadeverine do not influence the formation of this N-nitrosamine. Spermidine and cadeverine cause a significant increase of NPIP. Beside N-nitrosopyrrolidine (NPYR) in some rare cases, no other volatile N-nitrosamines are detected.

N-nitrosamines are meant to be probable or possible carcinogenic components, possibly formed out of a reaction between nitrite and N-containing substances such as amino acids and secondary amines. Nitrite is often used for processing meat products because of its colouring and antimicrobial properties. During this experimental setup, the influence of proline, hydroxyproline or pyrrolidine on N-nitrosamine formation in meat samples was evaluated. The N-nitrosamines concentrations were measured with gas chromatography-thermal energy analyzer. Only the concentrations of N-nitrosodimethylamine and N-nitrosopyrrolidine were found above the limit of detection in a number of tested experimental conditions. The concentration of these two N-nitrosamines was modelled as a function of temperature and nitrite concentration for different situations (presence or absence of added natural N-containing meat components). It could be concluded that proline and pyrrolidine promoted the formation of N-nitrosopyrrolidine. It could also be confirmed that the higher the temperature of the meat processing procedure and the higher the sodium nitrite amounts added, the higher were the yields of the respective N-nitrosamines.

N-Nitrosamines are formed in a multi-step reaction of nitrite with free amino acids and amines in the meat products. The aim of this study was to determine the role of proline and hydroxyproline in N-nitrosamines formation during heating of cured meat. A lean meat model was used with different nitrite concentrations (0, 120, and 480mg/kg), and addition of proline and hydroxyproline (1000mg/kg), followed by heating at different temperatures. Volatile nitrosamines were analyzed with GC-TEA. The nitrosamine content never exceeded 10μg/kg and stayedLOQ as long as the nitrite level of 120mg/kg was not surpassed. The importance of proline as a precursor for N-nitrosamine formation was confirmed. In contrast, hydroxyproline inhibited NPYR formation (N-nitrosopyrrolidine) because no traces were found after addition of hydroxyproline. NPYR formation was not related to nitrite, but was significantly influenced by temperature (⩾200°C) and proline. NDMA-presence (N-nitrosodimethylamine) in heated meat products was influenced by nitrite and temperatures120°C.

Aims: To investigate microbial diversity and population dynamics of spoilagesensitive modified-atmosphere-packaged (MAP) artisan-type cooked ham in relation to storage temperature. Methods and Results: Modified-atmosphere-packaged cooked ham samples were stored at different temperatures (4, 7, 12 and 26� C). Traditional methods were combined with polymerase chain reaction (PCR)-based techniques, i.e. a culture-dependent, repetitive DNA sequence-based method (rep-PCR) and a culture-independent approach (PCR-denaturing gradient gel electrophoresis of 16S rRNA gene fragments; PCR-DGGE). rep-PCR on DNA extracted from MRS isolates indicated that Leuconostoc carnosum and Enterococcus faecalis prevailed at all temperatures, with the latter becoming more important above 7� C. PCR-DGGE indicated the additional presence of Carnobacterium divergens and Brochothrix thermosphacta at all temperatures. Discriminant analysis related variation within the Leuc. carnosum cluster to the storage temperature. High performance liquid chromatography revealed that lactic acid was the main metabolite because of glucose consumption. Conclusions: Leuconostoc carnosum, C. divergens, E. faecalis and Br. thermosphacta are the main spoilage bacteria of artisan-type MAP cooked ham. Their population dynamics are affected by storage temperature. Significance and Impact of the Study: Temperature can condition the development of spoilage in artisan-type MAP cooked ham, acting at both species and biotype level.

The Mediterranean Forecasting system Pilot Project has concluded its activities in 2001, achieving the following goals: 1. Realization of the first high-frequency (twice a month) Voluntary Observing Ship (VOS) system for the Mediterranean Sea with XBT profiles for the upper thermocline (0-700 m) and 12 n.m. along track nominal resolution; 2. Realization of the first Mediterranean Multidisciplinary Moored Array (M3A) system for the Near-Real-Time (NRT) acquisition of physical and biochemical observations. The actual observations consists of: air-sea interaction parameters, upper thermocline (0-500 m) temperature, salinity, oxygen and currents, euphotic zone (0-100 m) chlorophyll, nutrients, Photosinthetically Available Radiation (PAR) and turbidity; 3. Analysis and NRT dissemination of high quality along track Sea Level Anomaly (SLA), Sea Surface Temperature (SST) data from satellite sensors to be assimilated into the forecasting model; 4. Assembly and implementation of a multivariate Reduced Order Optimal Interpolation scheme (ROOI) for assimilation in NRT of all available data, in particular, SLA and VOS-XBT profiles; 5. Demonstration of the practical feasibility of NRT ten day forecasts at the Mediterranean basin scale with resolution of 0.125° in latitude and longitude. The analysis or nowcast is done once a week; 6. Development and implementation of nested regional (5 km) and shelf (2-3 km) models to simulate the seasonal variability. Four regional and nine shelf models were implemented successfully, nested within the forecasting model. The implementation exercise was carried out in different region/shelf dynamical regimes and it was demonstrated that one-way nesting is practical and accurate; 7. Validation and calibration of a complex ecosystem model in data reach shelf areas, to prepare for forecasting in a future phase. The same ecosystem model is capable of reproducing the major features of the primary producers' carbon cycle in different regions and shelf areas. The model simulations were compared with the multidisciplinary M3A buoy observations and assimilation techniques were developed for the biochemical data. This paper overviews the methodological aspects of the research done, from the NRT observing system to the forecasting/modelling components and to the extensive validation/ calibration experiments carried out with regional/shelf and ecosystem models.

Accumulation of vinblastine has been studied in different types of cancer cells. We measured the intracellular concentration of vinblastine in MO4 cells and compared it to its extracellular concentration in culture medium. We observed that the ratio of accumulation, expressed as the ratio of intracellular over extracellular vinblastine, was dose-dependent. An initial accumulation level was reached within 30 min and a second dose-induced level after 48 hours. This remained constant for another 5 days. Intracellular accumulation was also seen for vincristine and vindesine but here the phenomenon was less dose-dependent and the maximum level was reached after 6 hours. The accumulation ratio of a single vinca alkaloid in MO4 cells is not different from combined simultaneous exposure with 2 or 3 of the drugs. Energy blocking by sodium azide resulted in an inhibition of the supplementary but not the initial level of vinblastine accumulation. After washing out the medium for vinblastine the intracellular concentration remained about 60 micrograms/ml for 1 microgram/ml vinblastine added to the medium. Based on these results, it is concluded that the accumulation of vinblastine is only partially based on an energy mediated mechanism, in which binding of the drug to at least two types of sites may play an important role.

In vitro fermentations with the gastro-intestinal flora of 18 treated piglets (Control, Virginiamycin, Spiramycin) were carried out to study the influence of Nutritional doses of Virginiamycin and Spiramycin on the composition of the microflora. Each total flora was used for three different incubations: Control, 50 ppm Virginiamycin, 50 ppm Spiramycin. To obtain comparable results with experiments in vivo, an artificial fermentation medium was made on the basis of several chemical analyses of intestinal contents. The treatments with nutritional doses in vivo had little influence on the different in vitro fermentations. Addition of Spiramycin during incubation was of little influence on the growth and the composition of the flora. Virginiamycin on the other hand caused marked changes in the gastro-intestinal microflora, such as a decrease of the total growth and a decrease in the number of Lactobacilli and Enterococci, combined with a slight increase of the Gram negative aerobic population.

Chemical analysis was carried out on 54 in vitro fermentations to study the influence of nutritional doses of Virginiamycin and Spiramycin on the metabolic activity of the gastro-intestinal flora of 18 in vivo treated piglets. Changes in the decomposition of glucose and the production of NH3, volatile acids and lactic acid are recorded in function of time. These results are in good accordance with changes noted in the composition of the bacterial flora, such as a marked decrease in the production of lactic acid, caused by Virginiamycin, combined with a decrease in the number of Lactobacilli and Enterococci. Virginiamycin caused marked changes in the metabolic activity of certain groups of bacteria, while there was only a slight effect noted for Spiramycin, although in vivo treatments with this antibiotic still show up in the results of the in vitro incubations. The overall results indicate that both antibiotics have marked influences on the intestinal flora of the pig, either by selective inhibiting of the flora resulting in a change of the metabolities formed, either by a change in the metabolic activity of some bacterial groups.