Migration Phenomenon in Food Packaging. Food–Package Interactions, Mechanisms, Types of Migrants, Testing and Relative Legislation—A Review

The development of convenient and low-cost packages, together with the increased consumer demands for safer products, have resulted in the conduction of extensive research and the publication of numerous studies related to the phenomenon of migration. The large number of synthetic materials used for the manufacture of packages makes the evaluation of the food–package interactions quite complicated. Different parameters such as the nature of the food of interest, the type of food–package contact, the time and temperature of contact, the packaging materials used, the properties of the migrating substances, as well as the amount of potential migrants contained in the packaging materials, can drastically affect the migration rate and extent. Due to the extreme variety of foods used, several food simulants have been suggested and applied for testing the migration phenomenon under various laboratory conditions. The use of many of those simulants is defined by national and international legislation. This review article covers the main migration phenomena, which are related to the most commonly used packaging materials. It is clearly demonstrated that the complexity of the migration phenomena requires more research to establish internationally accepted risk management procedures and standardised testing methods.     

Application of ISO 22000 and comparison with HACCP on industrial processing of common octopus (Octopus vulgaris) – Part I

Critical control points (CCPs) were identified in the risk assessment of octopus ( Octopus vulgaris ) processing and implemented in the hazard analysis critical control point (HACCP) plan. In the hazard analysis worksheet the different hazards were identified at each processing stage, whereas in the HACCP plan each CCP is identified and accompanied with the relevant significant hazard, critical limit, monitoring of the CCP and corrective actions. In this work comparison of ISO 22000 analysis with HACCP is carried out over octopus processing and packaging. ISO 22000 Analysis Worksheet was employed for determination of some prerequisite programmes (PrPs). Comparison between the two systems has been carried out using the hazard analysis worksheet. The PrPs are the main difference between the two systems. The incorporation of PrPs in the ISO 22000 made the system more flexible as a smaller number of CCPs was introduced.     

Assessment and energy implications of street air temperature cooling by shade tress in Athens (Greece) under extremely hot weather conditions

Air temperature measurements under the vegetation canopy of trees in suburban streets and at reference points were carried out under mostly light wind conditions in five streets in the city of Athens (Greece) during a short exceptionally hot weather period in 2007. The average cooling effect at 1400 h (LST) was found to range from 0.5 to 1.6 °C and at 1700 h (LST) from 0.4 to 2.2 °C; the highest cooling effect of 2.2 °C was found to be reached in a street with high tree shaded area and minimal traffic load. These results imply the passive cooling potential of shade trees. The trees cooling effect values obtained for Athens, however, were found to be lower than the ones reported in similar studies in the Mediterranean region. In terms of residential energy implications, the elaboration of the results using simplified assumptions showed that the current level of tree cover in the examined streets may reduce summer time consumption for air conditioning during the day by 2.6–8.6% and during peak hours by 2.9–9.7%.     

Effects of retinoids on proliferation and plasminogen activator expression in a bovine mammary epithelial cell line

Effects of two natural (retinol and retinoic acid, RA) and one synthetic N-(4-hydroxyphenyl) retinamide (4-HPR) retinoids on proliferation and expression of urokinase-plasminogen activator (u-PA) by bovine mammary epithelial cells were examined. The BME-UV1 established bovine mammary epithelial cell line was used as a model system. All retinoids tested (retinol, RA and 4-HPR) were effective inhibitors of cell proliferation. When cells were cultured in the absence of fetal bovine calf serum (FBCS), inhibition occurred at concentrations as low as 1 nM for all retinoids tested. The effect of retinoids on cell proliferation was not dose-related when cells were cultured in the absence of FBCS. All retinoids (retinol, RA, 4-HPR), when used in the range 1 nM-10 microM (noncytotoxic concentrations), were equally effective and had identical inhibition patterns. Inhibition of cell proliferation by RA was apparent by 6 h and was higher after 24 h in culture. In contrast, when cells were cultured in the presence of FBCS, the effect of RA and retinol on cell proliferation was dose-related. RA and retinol inhibited cell proliferation (P<0.01) when added to the culture medium in concentrations as low as 10 nM and 100 nM, respectively. 4-HPR was inhibitory (P<0.01) in concentrations as low as 1 nM. Higher concentrations of 4-HPR in the range 1 nM-1 microM had no further effect on cell proliferation. None of the retinoids tested, when added to cultures in the presence or absence of FBCS, could completely arrest cell proliferation at noncytotoxic concentrations. RA at 1 microM inhibited (P<0.05) insulin or IGF-I-induced cell proliferation but had no effect (P>0.05) on u-PA mRNA levels or u-PA activity. Furthermore, RA inhibited cell proliferation in the presence of FBCS but had no effect (P>0.05) on u-PA mRNA levels. Thus, retinoids are effective inhibitors of bovine mammary epithelial cell proliferation and this growth inhibition does not seem to correlate with any changes in u-PA mRNA or u-PA activity.     

Characterization of NAD-dependent alcohol dehydrogenase enzymes of strawberry's achenes (Fragaria x ananassa cv. Elsanta) and comparison with respective enzymes from Methylobacterium extorquens

Achenes were isolated from strawberries fruits, while the methylotroph Methylobacterium extorquens (strain with CABI registration number IMI 369321), which has been isolated from strawberry (Fragaria x ananassa cv. Elsanta) callus cultures, was grown on a mixture of methanol (0.25% v/v) and 1,2-propanediol (0.75% v/v). The Alcohol Dehydrogenase (ADH) enzymatic activities of the achenes were assessed and the optimum pH for ADH activity was found to be pH 10.0. Enzyme assays were carried out in order to define the best substrate specificity at pH = 10.0. The best substrates were found to be ethanol (Km = 5.950 mM) and methanol (Km = 12.610 mM). Only enzymes from the bacterium showed capability of using aldehydes - especially formaldehyde - as substrates. A wide variety of metals as well as EDTA and NaN₃ were shown to decrease the enzymatic activity. Furthermore, SDS-PAGE Electrophoresis experiments showed Molecular Weight of 47.0 kDa for the Alcohol Dehydrogenase from achenes of strawberries (Fragaria x ananassa). Additional experiments were conducted in order to define certain thermodynamic properties of the enzymes, by using the dehydrogenation activities of these three enzyme sources which were calculated by measuring the absorption of NADH at 340 nm, in the Arrhenius equation.     

Thermal oxidation of vanillin affects its antioxidant and antimicrobial properties

Accelerated oxidation of vanillin was studied by isothermal and non-isothermal differential scanning calorimetry (DSC) in model solutions. Exothermic peaks of DSC thermograms, due to the oxidation of vanillin, were observed. Vanillin oxidation to vanillic acid was confirmed by the detection of vanillic acid in heated vanillin samples using GC–MS. The effect of temperature on vanillin oxidation was studied by conducting DSC experiments with pure vanillin at several different final temperatures and by subsequent determination of vanillin and vanillic acid by GC–MS.     

Ring width, latewood proportion and dry density in stems of Pinus brutia Ten.

This study examined basic characteristics of stem wood produced in Pinus brutia Ten. reforestations in Northeastern Greece. Sixteen dominant trees growing at good and medium site qualities were felled at 14–22 years. Site quality classification was based on site quality surrogates and confirmed by using site index curves that were created for a neighbouring area. Discs were taken at three stem positions (base, middle, top) to study variations in ring width, latewood proportion and dry density. Generally, at both good and medium sites, ring width was found to increase towards the top of the stems while latewood proportion and dry density showed a negative relationship with stem height. Radial variability trends were similar at all heights, and at both sites, revealing a rapid increase for ring width in the first 3–6 annual rings followed by a decrease towards the bark, a gradual increase for latewood proportion and no specific change for dry density. Comparisons between wood material produced during the same growth period (2005–2001) showed statistically significant differences among sampling heights in all cases except for dry density in medium sites. At the base of the stems, mean ring width and dry density were significantly (P?≤0.05) higher at good sites (3.6 mm and 0.53 g/cm³) than at medium sites (3.0 mm and 0.50 g/cm³). However, the differences between the sites are of small magnitude and therefore have limited practical impact on wood processing. The availability of such data is useful in utilising small-dimension timber of brutia pine.     

Investigating the concept of meat quality from the consumers' perspective: The case of Greece

Recent unfortunate food incidents increased consumers' concern about food and especially meat quality. The perception that meat is a hazardous commodity to consume resulted in a stabilization of the, so far increasing, meat consumption in Greece, as well as in the EU. The present survey aims to identify the general trends of meat consumption in Greece, define through factor analysis the way consumers perceive the concept of meat quality and explore by means of cluster analysis the existence of specific consumer types in relation to meat quality perceptions, with clear-cut and statistically solid socio-demographic and behavioural profile .The frequency of meat purchasing and consumption is particularly high, while meat is present in the everyday plate of Greeks in almost any expression of their family and social life. Meat preference is mainly evaluated on the basis of pleasure derived from taste, which has to be evaluated according to visual quality cues (e.g., colour, leanness, etc.). Different consumer types with clear-cut profile are found to evaluate meat quality differently, based on different quality dimensions, such as visual quality, labels and brand name, nutritional value and microbial or chemical safety.     

Identification, quantification, and synthesis of a novel dimethoxylated polybrominated biphenyl in marine mammals caught off the coast of Japan

Bioaccumulation of persistent organic compounds can eventually lead to concentrations in wildlife and humans that are deleterious to health. The present paper documents the identification, quantification, and synthesis of a novel compound, 2,2'-dimethoxy-3,3',5,5'-tetrabromobiphenyl (2,2'-diMeO-BB80), present in the marine mammals Striped dolphin (Stenella coeruleoalba), Bottlenose dolphin (Tursiops truncatus), Minke whale (Balaenoptera acutorostrata), and Baird's beaked whale (Berardius bairdii) caught in the Pacific Ocean. Identification was based on comparison of the relative retention times of the compound on two gas chromatographic columns of different polarities to those of an authentic standard. Furthermore, this identification was also supported by comparison of the full scan mass spectrometric data collected employing electron ionization (El), positive ion chemical ionization (PICI), and electron capture negative ionization (ECNI). The concentrations of 2,2'-diMeO-BB80 in the samples ranged from 12 to 800 ng/g lipid, making this consistently one of the most abundant compounds among those analyzed, including polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCDD), and methoxylated PBDEs. The known occurrence of 3,3',5,5'-tetrabromo-2,2'-biphenyldiol (2,2'-diOH-BB80) in the marine environment as a natural product suggests that its methylated derivative, 2,2'-diMeO-BB80, is also of natural origin. To obtain the necessary authentic standards, synthesis was performed of 2,2'-diMeO-BB80 and the known natural product 2',6-dimethoxy-2,3',4,5'-tetrabromodiphenyl ether (2',6-diMeO-BDE68).     

A Framework for Dry Period Low Flow Forecasting in Mediterranean Streams

The objective of this article is to provide a simple and effective tool for low flow forecasting up to six months ahead, with minimal data requirements, i.e. flow observations retrieved at the end of wet period (first half of April, for the Mediterranean region). The core of the methodological framework is the exponential decay function, while the typical split-sample approach for model calibration, which is known to suffer from the dependence on the selection of the calibration data set, is enhanced by introducing the so-called Randomly Selected Multiple Subsets (RSMS) calibration procedure. Moreover, we introduce and employ a modified efficiency metric, since in this modelling context the classical Nash-Sutcliffe efficiency yields unrealistically high performance. The proposed framework is evaluated at 25 Mediterranean rivers of different scales and flow dynamics, including streams with intermittent regime. Initially, signal processing and data smoothing techniques are applied to the raw hydrograph, in order to cut-off high flows that are due to flood events occurring in dry periods, and allow for keeping the decaying form of the baseflow component. We then employ the linear reservoir model to extract the annually varying recession coefficient, and, then, attempt to explain its median value (over a number of years) on the basis of typical hydrological indices and the catchment area. Next, we run the model in forecasting mode, by considering that the recession coefficient of each dry period ahead is a linear function of the observed flow at the end of the wet period. In most of the examined catchments, the model exhibits very satisfactory predictive capacity and is also robust, as indicated by the limited variability of the optimized model parameters across randomly selected calibration sets.