Contamination of dry foods with trimethyldiphenylmethanes by migration from recycled paper and board packaging

Contamination of foods with trimethyldiphenylmethanes is reported and the origin is shown to be migration from food packaging materials of which the use of recycled carbonless copy paper was found to be the major source. This chemical is one of the solvents used in the carbonless copy paper and its presence in food and the environment has not been previously identified. In this paper we have pursued previous studies on diisopropylnaphthalenes and hydrogenated terphenyls contamination from packaging and now report the identification of this new food contaminant and present evidence of its source. Solid foods such as egg pasta, barley coffee and rice were analysed by GC/MS and a mean concentration of 18 µg/kg of trimethyldiphenylmethanes was found. Extracts from carbonless copy paper were analysed by proton NMR to characterize the trimethyldiphenylmethanes. Since trimethyldiphenylmethanes are found in solid food together with diisopropylnaphthalenes, and considering their similar chemical character, they may follow the same migration pathway as one another.     

ENEA extremity dosemeter based on LiF(Mg,Cu,P) to evaluate Hp(3,alpha)

Recent epidemiological studies suggest a rather low-dose threshold (<0.5 Gy) for the induction of a cataract of the eye lens. Some other studies even assume that there is no threshold at all. Therefore, protection measures have to be optimised and current dose limits for the eye lens may be reduced in the future. ICRP Publication 103 on H(p)(d), in §(136), reads that '… a depth d = 3 mm has been proposed for the rare case of monitoring the dose to the lens of the eye. In practice, however, H(p)(3) has rarely been monitored and H(p)(0.07) can be used for the same monitoring purpose… '. As recommended on the EU 'Technical recommendations for monitoring individuals occupationally exposed to external radiation', a test on the ENEA TL extremity dosemeter is herein reported. The results within the actual EU founded Optimization of RAdiation protection for MEDical staff (ORAMED) Project, whose WP2 is aimed at the quantity H(p)(3) and eye lens dosimetry in practice, are taken into account. The paper summarises the main aspects of the study carried out at ENEA-Radiation Protection Institute (Bologna, Italy) to provide practical solutions (in the use and the design) to evaluate the response of the ENEA TL extremity dosemeter in terms of H(p)(3).     

Advanced noise reduction techniques for ultra-low phase noise optical-to-microwave division with femtosecond fiber combs

We report what we believe to be the lowest phase noise optical-to-microwave frequency division using fiber-based femtosecond optical frequency combs: a residual phase noise of -120 dBc/Hz at 1 Hz offset from an 11.55 GHz carrier frequency. Furthermore, we report a detailed investigation into the fundamental noise sources which affect the division process itself. Two frequency combs with quasi-identical configurations are referenced to a common ultrastable cavity laser source. To identify each of the limiting effects, we implement an ultra-low noise carrier-suppression measurement system, which avoids the detection and amplification noise of more conventional techniques. This technique suppresses these unwanted sources of noise to very low levels. In the Fourier frequency range of ～200 Hz to 100 kHz, a feed-forward technique based on a voltage-controlled phase shifter delivers a further noise reduction of 10 dB. For lower Fourier frequencies, optical power stabilization is implemented to reduce the relative intensity noise which causes unwanted phase noise through power-to-phase conversion in the detector. We implement and compare two possible control schemes based on an acousto-optical modulator and comb pump current. We also present wideband measurements of the relative intensity noise of the fiber comb.     

3T Renal 23Na-MRI: effects of desmopressin in patients with central diabetes insipidus

Purpose

The purpose of this prospective study was to assess physiologic changes in the renal corticomedullary ²³Na-concentration ([²³Na]) gradient with ²³Na-MRI at 3.0T in patients with central diabetes insipidus (CDI) before and after intranasal administration of 20 μg desmopressin (DDAVP).

Methods and materials

Four patients with CDI (all male, mean age 60.2 years) were included in this IRB-approved study. For ²³Na-imaging, a 3D density adapted, radial GRE-sequence (TE = 0.55 ms; TR = 120 ms; projections = 8,000; spatial resolution = 5 × 5 × 5 mm³) was used in combination with a dedicated ²³Na-coil and reference phantoms. The corticomedullary [²³Na] gradient (in mmol/L/mm) was calculated pixel-by-pixel along a linear region-of-interest (ROI) spanning from the renal cortex in the direction of the medulla. Mean ± SDs of [²³Na] were calculated for each patient as well as for the entire group.

Results

Mean [²³Na] increased along the corticomedullary gradient from the cortex (pre-DDAVP 38.0 ± 6.3 mmol/L vs. post-DDAVP 30.7 ± 3.5 mmol/L) to the medulla (pre-DDAVP 71.6 ± 14.8 mmol/L vs. post-DDAVP 59.7 ± 10.8 mmol/L). The overall mean decrease of [²³Na] after DDAVP administration was 17.1 ± 1.1 %.

Conclusion

²³Na-MRI with state-of-the-art techniques at 3T depicts the physiologic renal response to the administration of desmopressin in patients with central diabetes insipidus.     

Effect of irrigation and lactic acid bacteria inoculants on the phenolic fraction,fermentation and sensory characteristics of olive (Olea europaea L. cv. Ascolana tenera) fruits

Plant productivity, phenolic profile and natural fermentation, with and without lactic acid bacteria inoculants, were investigated in olive fruit of Ascolana tenera growing under different irrigation regimes. A rainfed control and two treatments receiving a water depth equivalent to 33 and 66% of the estimated crop evapotranspiration (ETc) from the pit hardening stage and a treatment with 66% of ETc during the entire season (25 May‐4 October), were tested. Olive vigour increased with irrigation, which also induced a fresh yield enhancement, mainly due to the increase in fruit size. The differences between treatments were less evident for fruit number per tree and pulp/stone ratio. The phenolic content increased in water deficit‐stressed olives and differences were detected in the concentrations of individual phenolic compounds. Olive oil content and fatty acids composition appeared scarcely affected by irrigation. Values of pH, acidity, sugars, phenolic composition and microbial population were monitored during olive fermentation. Extracts of freshly harvested olive fruits exhibited significantly higher phenolic content than extracts of processed olives. The interaction of irrigation and fermentation appeared to have a significant effect on the chemical and sensory characteristics of the end product. The bitter taste of olive fruit was positively correlated with the level of total phenolics, but negatively correlated with the overall acceptability for direct consumption. The fermentation process was accelerated in the presence of lactic acid bacteria inoculants, indicating the potential use of these microorganisms as quality control markers in table olives during processing. Copyright © 2006 Society of Chemical Industry     

Functionality of enterococci in dairy products

Enterococci have important implications in the dairy industry. They occur as nonstarter lactic acid bacteria (NSLAB) in a variety of cheeses, especially artisan cheeses produced in southern Europe from raw or pasteurised milk, and in natural milk or whey starter cultures. They play an acknowledged role in the development of sensory characteristics during ripening of many cheeses and have been also used as components of cheese starter cultures. The positive influence of enterococci on cheese seems due to specific biochemical traits such as lipolytic activity, citrate utilisation, and production of aromatic volatile compounds. Some enterococci of dairy origin have also been reported to produce bacteriocins (enterocins) inhibitory against food spoilage or pathogenic bacteria, such as Listeria monocytogenes, Staphylococcus aureus, Vibrio cholerae, Clostridium spp., and Bacillus spp. The technological application of enterocins, shown to be produced during cheese manufacture, led to propose enterococci as adjunct starter or protective cultures in cheeses. There is evidence that enterococci, either added as adjunct starters or present as nonstarter NSLAB, could find potential application in the processing of some fermented dairy products. Literature suggest that the complex biochemical and ecological phenomena explaining the technological functionality of the enterococci in dairy products, are still to be fully understood. Clearly, the clinical research on enterococci underlines also that the safety of dairy products containing enterococci is an issue that the industry must carefully address before proceeding to their application.     

Characterization and probiotic potential of Lactobacillus plantarum strains isolated from cheeses

Ninety-eight Lactobacillus plantarum strains isolated from Italian and Argentinean cheeses were evaluated for probiotic potential. After a preliminary subtractive screening based on the presence of msa and bsh genes, 27 strains were characterized. In general, the selected strains showed high resistance to lysozyme, good adaptation to simulated gastric juice, and a moderate to low bile tolerance. The capacity to agglutinate yeast cells in a mannose-specific manner, as well as the cell surface hydrophobicity was found to be variable among strains. Very high β-galactosidase activity was shown by a considerable number of the tested strains, whereas variable prebiotic utilization ability was observed. Only tetracycline resistance was observed in two highly resistant strains which harbored the tetM gene, whereas none of the strains showed β-glucuronidase activity or was capable of inhibiting pathogens. Three strains (Lp790, Lp813, and Lp998) were tested by in vivo trials. A considerable heterogeneity was found among a number of L. plantarum strains screened in this study, leading to the design of multiple cultures to cooperatively link strains showing the widest range of useful traits. Among the selected strains, Lp790, Lp813, and Lp998 showed the best probiotic potential and would be promising candidates for inclusion as starter cultures for the manufacture of probiotic fermented foods.     

Low-Temperature Thermoelectric Properties of Co<Subscript>0.9</Subscript>Fe<Subscript>0.1</Subscript>Sb<Subscript>3</Subscript>-Based Skutterudite Nanocomposites with FeSb<Subscript>2</Subscript> Nanoinclusions

Bulk thermoelectric nanocomposite materials have great potential to exhibit higher ZT due to effects arising from their nanostructure. Herein, we report low-temperature thermoelectric properties of Co_0.9Fe_0.1Sb₃-based skutterudite nanocomposites containing FeSb₂ nanoinclusions. These nanocomposites can be easily synthesized by melting and rapid water quenching. The nanoscale FeSb₂ precipitates are well dispersed in the skutterudite matrix and reduce the lattice thermal conductivity due to additional phonon scattering from nanoscopic interfaces. Moreover, the nanocomposite samples also exhibit enhanced Seebeck coefficients relative to regular iron-substituted skutterudite samples. As a result, our best nanocomposite sample boasts a ZT = 0.041 at 300 K, which is nearly three times as large as that for Co_0.9Fe_0.1Sb₃ previously reported.     

Antimutagens in food

Foods are complex mixtures containing both carcinogenic and anticarcinogenic substances. During the past ten years, there has been increasing interest in individuating and establishing the roles of the various antimutagens/anticarcinogens in the diet. Several compounds appear to protect against both mutagenic and carcinogenic effects. Short-term tests, in particular, have proven to be important tools for elucidating the mechanisms of action of these substances.