Assessment of microbial quality of commercial and home-made tiger-nut beverages.

AIMS: We aimed to assess the microbiological quality of Spanish commercial tiger-nut beverages as well as home-made samples collected from supermarkets, street vendors, juice bars and ice-cream parlours located in Valencia. METHODS AND RESULTS: Microbiological analysis of 44 tiger-nut beverages samples were carried out according to International Standard Organization (ISO) norms and published works which included the total viable count, Enterobacteriaceae, Escherichia coli, Staphylococcus aureus, Salmonella, Bacillus cereus, yeasts, moulds, Yersinia enterocolitca, Clostridium perfringens, Vibrio spp. and Listeria monocytogenes. The obtained results indicated that all the commercial samples were below the detection limit for the viable microorganisms. Results of analysis of those home-made tiger-nut samples revealed that 67% (16 samples) harboured total plate counts while the rest of samples were free from these microorganisms. Enterobacteriaceae were detected in 62% (15 samples). E. coli were found in only one sample (4%), yeasts and moulds were detected in 62% (15 samples) each, Shigella was found in 21% (five samples); however, all samples were free from S. aureus, Salmonella, Y. enterocolotica, C. perfringens, Vibrio spp. and L. monocytogenes. CONCLUSIONS: These results reflected that there exists a rather high contamination level in home-made tiger-nut beverages indicating the need to apply correct and strict HACCP system(s) during manufacturing and storage of these food products. SIGNIFICANCE AND IMPACT OF STUDY: This study demonstrates the great need to carry out microbiological tests frequently in these products and even more the need to apply correct HACCP system (s). Tiger-nut beverages are especially well-known products in Spain, hence it is extremely important to ensure an adequate microbiological quality to guarantee consumers health.

Concentration-Dependent Protection by Ethanol Extract of Propolis against γ-Ray-Induced Chromosome Damage in Human Blood Lymphocytes.

Radioprotection with natural products may be relevant to the mitigation of ionizing radiation-induced damage in mammalian systems; in this sense, propolis extracts have shown effects such as antioxidant, antitumoral, anti-inflammatory, and immunostimulant. We report for the first time a cytogenetic study to evaluate the radioprotective effect, in vitro, of propolis against radiation-induced chromosomal damage. Lymphocytes were cultured with increasing concentrations of ethanol extract of propolis (EEP), including 20, 40, 120, 250, 500, 750, 1000, and 2000 µg mL(-1) and then exposed to 2 Gy γ-rays. A significant and concentration-dependent decrease is observed in the frequency of chromosome aberrations in samples treated with EEP. The protection against the formation of dicentrics was concentration-dependent, with a maximum protection at 120 µg mL(-1) of EEP. The observed frequency of dicentrics is described as negative exponential function, indicating that the maximum protectible fraction of dicentrics is approximately 44%. Free radical scavenging and antioxidant activities are the mechanisms that these substances use to protect cells from ionizing radiation.

Realising the European network of biodosimetry: RENEB-status quo.

Creating a sustainable network in biological and retrospective dosimetry that involves a large number of experienced laboratories throughout the European Union (EU) will significantly improve the accident and emergency response capabilities in case of a large-scale radiological emergency. A well-organised cooperative action involving EU laboratories will offer the best chance for fast and trustworthy dose assessments that are urgently needed in an emergency situation. To this end, the EC supports the establishment of a European network in biological dosimetry (RENEB). The RENEB project started in January 2012 involving cooperation of 23 organisations from 16 European countries. The purpose of RENEB is to increase the biodosimetry capacities in case of large-scale radiological emergency scenarios. The progress of the project since its inception is presented, comprising the consolidation process of the network with its operational platform, intercomparison exercises, training activities, proceedings in quality assurance and horizon scanning for new methods and partners. Additionally, the benefit of the network for the radiation research community as a whole is addressed.

Virgin olive oil phenolic compounds: binding to human low density lipoprotein (LDL) and effect on LDL oxidation.

Oxidation of low density lipoproteins (LDL) appears to occur predominantly in arterial intima in microdomains sequestered from antioxidants of plasma. Therefore phenolic compounds which are able to bind LDL are good drug candidates for the effective prevention of lipid peroxidation and atherosclerotic processes. Plasma from healthy volunteers on nonsupplemented diets was incubated with virgin olive oil phenolic extracts (0-200 mg/l, caffeic acid equivalents). Phenolic compounds in LDL were measured by high-performance liquid chromatography-diode array detection (HPLC-DAD). Copper-mediated LDL oxidation was performed, and conjugated dienes formation was monitored. After plasma preincubation with olive oil phenolic compounds (OOPC), an increased OOPC-concentration dependent was observed in the total phenolic content of LDL (p < 0.001, ANOVA) as well as in the lag time before conjugated diene formation (p < 0.001, ANOVA). Rutin and four phenolics with flavonoid-like spectra were found to be bound to the LDL control. These phenolics, together with tyrosol which was not present in the LDL control, significantly increased in LDL (p < 0.05) after plasma incubation with OOPC. These results show the ability of tyrosol to bind LDL in vitro and the capacity of virgin olive oil phenolics to protect other phenolic compounds previously bound to LDL. These results provide further evidence that phenolic compounds bound to LDL are likely to protect LDL from oxidation.

Curcumin and trans-resveratrol exert cell cycle-dependent radioprotective or radiosensitizing effects as elucidated by the PCC and G2-assay.

Curcumin and trans-resveratrol are well-known antioxidant polyphenols with radiomodulatory properties, radioprotecting non-cancerous cells while radiosensitizing tumor cells. This dual action may be the result of their radical scavenging properties and their effects on cell-cycle checkpoints that are activated in response to radiation-induced chromosomal damage. It could be also caused by their effect on regulatory pathways with impact on detoxification enzymes, the up-regulation of endogenous protective systems, and cell-cycle-dependent processes of DNA damage. This work aims to elucidate the mechanisms underlying the dual action of these polyphenols and investigates under which conditions they exhibit radioprotecting or radiosensitizing properties. The peripheral blood lymphocyte test system was used, applying concentrations ranging from 1.4 to 140µM curcumin and 2.2 to 220µM trans-resveratrol. The experimental design focuses first on their radioprotective effects in non-cycling lymphocytes, as uniquely visualized using cell fusion-mediated premature chromosome condensation, excluding, thus, cell-cycle interference to repair processes and activation of checkpoints. Second, the radiosensitizing potential of these chemicals on the induction of chromatid breaks in cultured lymphocytes following G2-phase irradiation was evaluated by a standardized G2-chromosomal radiosensitivity predictive assay. This assay uses caffeine for G2-checkpoint abrogation and it was applied to obtain an internal control for radiosensitivity testing, which simulates conditions similar to those of the highly radiosensitive lymphocytes of AT patients. The results demonstrate for the first time the cell-cycle-dependent action of these polyphenols. When non-cycling cells are irradiated, the radioprotective properties of curcumin and trans-resveratrol are more prominent. However, when cycling cells are irradiated during G2-phase, the radiosensitizing features of these compounds are more pronounced. This observation offers a new biological basis for the mechanisms underlying the action of these polyphenols in cancer radiotherapy.

Assessment in vitro of cytogenetic and genotoxic effects of propolis on human lymphocytes.

We evaluated the genetic damage by ethanolic extract of propolis (EEP) induced to human lymphocytes which were exposed to increasing concentrations (0-2000µgml(-1)). The results indicated that EEP reduced significantly the mitotic index (MI) and proliferation index (PI) when high concentrations of EEP were used. Sister chromatid exchange (SCE) rates indicated that EEP could have genotoxic effects at high concentrations. Exposure of the cells to the amount of ethanol used as solvent did not alter either the MI and cell proliferation kinetics (CPK), or the rate of SCE. The results showed: (a) statistical increase in the percentage the cells with CAs and in the frequency of SCE at the highest concentrations, (b) a decrease in MI and in the CPK values was observed, (c) no effect was noticed in negative controls. In conclusion, it can be assumed that high concentrations of EEP have a cyto and genotoxic effect, in vitro, for human peripheral lymphocytes.

One-year monitoring of aflatoxins and ochratoxin A in tiger-nuts and their beverages.

A sensitive and selective liquid chromatography-triple quadrupole-tandem mass spectrometry (LC-ESI-MS-MS) method was developed for the routine analysis of aflatoxins (AFB(1), AFB(2), AFG(1) and AFG(2)) and ochratoxin A (OTA) in tiger nuts and tiger-nut beverage (horchata). A matrix solid phase dispersion was adapted to eliminate lipidic interferences. The solid support was C(18), while the elution solvent was acetonitrile. Mean recoveries obtained at two fortification levels were 72-83% and 71-81% for horchata and tiger nut respectively with relative standard deviations (RSDs) <13% and 15% respectively. The LC-MS-MS method allowed quantification and identification at low levels in two matrices. The method was applied for the routine analysis of tiger-nuts and horchata samples collected from different supermarkets of Valencia (Spain) during one year (March 2009-March 2010). A total of 238 samples were analysed and 32 samples were found positives for OTA, AFB(1), AFB(2) and AFG(2).