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S Moret

Publications and source records attributed to S Moret.

15 recordsLinked to original sources
PubMed2004

Relative hopane content confirming the mineral origin of hydrocarbons contaminating foods and human milk.

Hopanes, triterpenoid hydrocarbons formed under geological conditions, were analysed to confirm the mineral origin of the unresolved complex mixtures of hydrocarbons observed in the gas chromatography with flame ionization detection chromatograms of human milk and certain foodstuffs. The 'relative hopane content' (RHC) is introduced, i.e. it is the area ratio of the sum of the hopanes and the paraffins in the same segment of the chromatogram. The RHC in various mineral oil products (motor oils, hydraulic oils, lubricating oils, Vaseline) was 3.4%, with a relative standard deviation of 19%. The RHC determined in samples of vegetable oils, mussels and clams as well as of human milk containing an unresolved complex mixture of hydrocarbons was in the same range, confirming that these samples were contaminated by mineral oil material.

Animals↗
PubMed2003

Occurrence of C15-C45 mineral paraffins in olives and olive oils.

Different classes of olive oils and other olive samples (olives, olive paste and olive pomace) collected during their production were analysed for mineral paraffins in the range of C(15)-C(45). None of the 22 extra virgin olive oils contained mineral paraffins above the detection limit of 1 mg kg(-1). Also, lampante virgin olive oil from the olive mill showed no detectable amounts, but olive oil from the market contained 6-30 mg kg(-1). This contamination cannot be attributed to the refining step, which, on the contrary, partially removes the more volatile hydrocarbons, but could result from transport. Olive-pomace oils obtained by second centrifugation contained 16-145 mg kg(-1) mineral paraffins, presumably because of contamination during storage of the pomace. All olive-pomace oils from solvent extraction contained more than 100 mg kg(-1) mineral paraffins, also mainly from storage. Deposition of particulate matter from the air, vehicle exhaust emissions and direct contamination from the bulldozers used to move the pomace were identified as potential sources.

Food Contamination↗
PubMed2000

Polycyclic aromatic hydrocarbons in edible fats and oils: occurrence and analytical methods.

This review deals with analytical methods for polycyclic aromatic hydrocarbon (PAH) determination in oils and fats. The data reported in the introduction deal with PAH dietary intake from this group of food and contamination levels recently found by some authors in different vegetable oils, stressing the importance of establishing a method suitable for routine analyses. Traditional sample preparation relies on tedious, time-consuming procedures. They generally consist of an extraction step (liquid-liquid partition, caffeine complexation, saponification) followed by one or more purification procedures (column chromatography, thin-layer chromatography, solid-phase extraction). The analytical determination is usually carried out by HPLC and spectrofluorometric detection, or through high-resolution capillary GC coupled to flame ionisation detection or mass spectrometry. LC is a valid alternative to the traditional sample preparation, and off-line LC-LC allows performing an accurate PAH analysis in less than 2 h. Also supercritical fluid extraction, allowing performing both extraction and clean-up in one combined step, is a promising technique. Hyphenated techniques such as LC-GC and LC-LC-GC seem to be very promising. A completely on-line method for alkylated PAH determination in oils or lipidic extracts contaminated with mineral oil involves a two-dimensional LC-step with intermediate eluent evaporation and GC transfer through a vaporiser/overflow interface.

Chromatography, Gas↗
PubMed2000

A rapid method for the quantitative determination of short-chain free volatile fatty acids from cheese.

The determination of free volatile fatty acids (FVFA) is of interest in the analysis of cheeses. As these compounds are components of taste and flavor, they give indications on metabolic reactions taking place during cheese ripening and can provide an evaluation of cheese defects and their causes. One of the most widely used methods for the determination of FVFA in cheese involves preliminary recovery from the matrix by steam distillation, followed by gas chromatography separation. Relatively high distillate volumes must be collected to achieve a quantitative yield of all the compounds of interest, so that, as a result, the solution is too diluted to achieve good instrumental sensitivity. In this paper, an alternative method for the determination of C2-C6 free carboxylic acids in cheeses involving the use of a Nukol capillary column and crotonic acid as internal standard is described. This method is quick and cheap, as the sample preparation is a simple extraction with water. The underivatized FVFA are then directly separated by gas chromatography. Using this method, all FVFA in cheeses can be quantified with good repeatability and excellent recovery.

Cheese↗
PubMed2000

The capacity of Enterobacteriaceae species to produce biogenic amines in cheese.

The amino acid decarboxylating activity and production of biogenic amines by 104 cheese-associated Enterobacteriaceae species (58 Enterobacter, 18 Serratia, eight Escherichia, seven Hafnia, six Arizona, four Citrobacter and three Klebsiella) were investigated. All strains could decarboxylate at least two amino acids in Möller's broth and in Niven's medium, and the decarboxylase activity was strain specific. In a laboratory medium containing all free amino acids, all strains could produce more than 100 ppm cadaverine, putrescine was produced by 96% of strains. Tyramine and histamine were produced in the lowest concentrations. A positive correlation existed between cadaverine concentration and Enterobacteriaceae counts in cheese, that may have caused the increase in decarboxylase content. This study suggests that it is possible to limit the presence of cadaverine in cheese, thereby controlling the Enterobacteriaceae counts, a sign of contamination during cheese making and/or storage.

Biogenic Amines↗
PubMed1999

Assessment of polycyclic aromatic hydrocarbon content of smoked fish by means of a fast HPLC/HPLC method.

Polycyclic aromatic hydrocarbon (PAH) concentrations in smoked food can reach levels hazardous for the human health, especially when the smoking procedure is carried out under uncontrolled conditions. In this work a simple and rapid method for the determination of PAHs in smoked fish samples is described. PAHs were extracted from the insoluble samples (together with fat substances) by homogenization with acidified chloroform. The fat extract was then submitted to a first LC sample preparation step (performed on a large silica column) to isolate PAHs from triglycerides. After reconcentration, the PAH fraction was finally injected into the reverse-phase analytical column. The proposed method, which presents good characteristics of recoveries and repeatability, was also used to analyze PAH content of some smoked trout samples packed under vacuum.

Animals↗
PubMed1996

On-line high-performance liquid chromatography-solvent evaporation-high-performance liquid chromatography-capillary gas chromatography-flame ionisation detection for the analysis of mineral oil polyaromatic hydrocarbons in fatty foods.

An automated on-line method is described that involves a first LC separation on a large column, evaporation of a 6-ml fraction in an on-line solvent evaporator, a second LC separation using a different mobile phase, fractionating the components of interest and transfer to GC through the in-line vaporizer/overflow interface. The method is designed for the injection of a large amount of food extract (e.g. up to 200 mg of fat) and is applied to the analysis of mineral oil material in a linseed oil.

Chromatography, Gas↗
PubMed1996

High-performance liquid chromatographic evaluation of biogenic amines in foods. An analysis of different methods of sample preparation in relation to food characteristics.

Biogenic amines are compounds formed by amino acid decarboxylation in fermented foods. Most of the methods for amine determination involve acid extraction followed by a liquid-liquid purification step. The different parameters which can influence amine recoveries are considered; experience with different foods such as cheese, fish and meat preserves are reported and for each of them the optimized analytical procedure is described. Data concerning recovery and repeatability of the method are also reported and the various factors that influence amine extraction are discussed. The possibility of applying direct derivatization without any other purification step is also considered.

Biogenic Amines↗
PubMed1995

Determination of polycyclic aromatic hydrocarbons in water and water-based alcoholic beverages.

This paper proposes a simple HPLC method for the determination of polycyclic aromatic hydrocarbons (PAHs) in water, wine and beer. Samples were purified by PAH collection in solid-phase extraction (SPE) and analysed by reversed-phase HPLC (Supelcosil LC-PAH column from Supelco). For the beer sample, recoveries amounted to 28% for naphthalene and varied from 57% to 103% for the other PAHs; results are quantitative starting from fluoranthene (FI, the seventh component eluted). Almost all the beer and wine samples showed the presence of benzo(b)fluoranthene (BbF), benzo(k)fluoranthene (BkF), benzo(a)pyrene (BaP), benz(ghi)perylene (BghiP) and indeno(1,2,3-cd)pyrene (IP), and in some cases there were traces of FI, benzo(a)anthracene (BaA) and dibenz(ah) anthracene (DBahA). Total contents of PAHs ranged from trace amounts to 0.72 ppb. Traces of BbF, BkF, BaP, BghiP and IP were also found in the wine samples.

Beer↗
PubMed1993

The influence of basal anxiety on unstimulated parotid and submandibular saliva.

Stress modifies numerous physiological variables, such as salivary secretion. The relation between salivary constituents, biophysical variables and personality traits defined by the Cattell's anxiety scale was studied. The main result was, that in the absence of stress, no statistically significant differences are to be found between the three groups defined on the Cattell scale.

Adult↗
PubMed1993

[Development and maturation of secretory cells in the trachea of human fetuses].

The number of tracheal epithelial secretory cells and their mucus secretions change during the course of human foetal development. The muco-secretory cells of the respiratory mucus and glands were studied in the trachea in 46 human foetuses with the aid of histochemical techniques, and ultrastructural examination. During the second trimester of pregnancy, the mucosecretory cells are very numerous in the surface epithelium for a transitory period, and secrete as much neutral mucin as acid mucin; these latter were predominantly sulphomucins. The glands appear progressively from the 13th week of development and remain almost exclusively of the mucous type until the second trimester. During the third trimester the serous cells appear but their number remains low. The mucosecretory surface epithelial cells are rare in this trimester but produce the same type of secretions. The role of secretory cells in utero in the foetus is poorly understood. Foetal secretions differ from the normal adult mucus cells but approach them with qualitative and quantitative differences observed in the mucus of irritated bronchi or those with scarring.

Embryonic and Fetal Development↗
PubMed1992

Improvement of extraction procedure for biogenic amines in foods and their high-performance liquid chromatographic determination.

A high-performance liquid chromatography method is described for the simultaneous determination of the biogenic amines tryptamine, 2-phenylethylamine, putrescine, cadaverine, histamine, tyramine, spermidine, and spermine in cheese. The optimization of the procedure for the extraction of amines from the matrix is described. The separation of dansyl derivatives of the amines was achieved by reversed-phase liquid chromatography with gradient elution, followed by UV detection at 254 nm. The mobile phase was acetonitrile-0.01 M phosphate buffer (pH 7)-water. Under these conditions, rapid elution of the amines in less than 13 min was obtained. Validation of the method included calibration experiments, addition of standard amines for the determination of amine recoveries and repeatability tests.

Biogenic Amines↗
PubMed1992

Human airway secretory cells during development and in mature airway epithelium.

The combined secretions of distinct secretory cells of the airway lining mucosa serve to keep the inspired air moist and free of potentially harmful dust particles, organisms and adsorbed gases. Apart from their role in protecting the respiratory zone of the lung, mucus-secreting cells act as pluripotential stem cells during foetal development and, in the adult, following mucosal injury. The variety of secretory cells include the mucous and serous cells of the surface and glandular epithelium, the non-ciliated bronchiolar (Clara) cell and the less frequent dense-core granulated (neuroendocrine) cell. The last-mentioned is the first type to differentiate at about 10 weeks of gestation; mucus-secreting cells are present from the 13th week of gestation, when mature ciliated cells are already present, and Clara cells begin to mature during the 19th week of human development. The alteration of secretory cell number and chemical composition of their secretions during the second trimester of foetal life is similar to that which occurs in chronic bronchitis in the adult. However, in hypersecretory disease the extent and site of the major change appear to be inappropriate to the defence of the lung.

Epithelial Cells↗
PubMed1981

[Cystadenomas and cystadenocarcinomas of the pancreas].

Benign or malignant cystadenoma of the pancreas is a rare but not exceptional tumor. Up to present, 300 of the former and 100 of the latter have been reported in the world literature. Three personal observations are reported, comprising 2 benign cystadenomas, the first discovered on abdominal palpation and the second after massive bleeding of gastric varices and thrombosis of the splenic vein. After removal of the tumor both patients were alive 20 and 7 1/2 years later respectively. Total excision of a cystadenocarcinoma in a third case required 90% pancreatectomy with ensuing diabetes. A review of the literature shows that total excision of a cystadenocarcinoma is always justified since the survival rate approximates 70%. This contrasts singularly with the catastrophic prognosis of pancreatic adenocarcinoma.

Cystadenocarcinoma↗