Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
1.
Food Microbiol ; 78: 110-113, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30497592

RESUMO

Irradiation of ground beef and beef liver inoculated with Escherichia coli O157 466 and DT66 and Salmonella Enteritidis 3313 were performed with gamma rays from cobalt-60 at refrigerated and frozen temperatures under air- and vacuum-packaged conditions. Results showed that D10 values for all pathogens in frozen beef liver were higher than those in frozen ground beef samples, with significant differences observed between the D10 values of E. coli O157 466 and S. Enteritidis 3313 under air-packaged conditions, as well as in E. coli O157 DT66 and S. Enteritidis 3313 under vacuum-packaged conditions. To verify effective bacterial inactivation under high bacterial-contamination levels (105-107 CFU/g), survival/death interfaces of E. coli O157 DT66 and S. Enteritidis 3313 inoculated in beef liver under vacuum-packaged and frozen conditions were constructed, with results suggesting that doses from 5.3 kGy to 5.5 kGy and 8.2 kGy-8.5 kGy would be sufficient to kill 105 CFU/g of E. coli O157 and S. Enteritidis 3313, respectively, at a 95%-99% predicted confidence interval. These results suggested that food matrixes containing high amounts of antioxidants (such as beef liver) and treated under frozen and vacuum-packaged conditions require additional consideration and evaluation for applications of irradiation treatment.


Assuntos
Escherichia coli O157/efeitos da radiação , Raios gama , Fígado/microbiologia , Fígado/efeitos da radiação , Viabilidade Microbiana/efeitos da radiação , Salmonella enteritidis/efeitos da radiação , Animais , Bovinos , Contagem de Colônia Microbiana , Escherichia coli O157/isolamento & purificação , Microbiologia de Alimentos/métodos , Embalagem de Alimentos/métodos , Conservação de Alimentos/métodos , Congelamento , Carne/microbiologia , Carne Vermelha/microbiologia , Carne Vermelha/efeitos da radiação , Salmonella enteritidis/isolamento & purificação , Temperatura , Vácuo
2.
J Toxicol Pathol ; 28(2): 99-107, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26028819

RESUMO

A 90-day oral toxicity test in rats was performed to evaluate the toxicity of 2-tetradecylcyclobutanone (2-tDCB), a unique radiolytic product of stearic acid. Six-week-old male and female F344 rats (n=15/group) were given 2-tDCB at concentrations of 0, 12, 60 and 300 ppm in a powder diet for 13 weeks. Slight dose-dependent increases in serum total protein and albumin in male rats were found, but these changes were not considered to be a toxic effect. The fasting, but not non-fasting, blood glucose levels of the male rats in the 300 ppm group and female rats in the 60 and 300 ppm groups were lower than those of the controls. Gas chromatography-mass spectrometry analysis showed dose-dependent accumulation of 2-tDCB in adipose tissue, notably in males. Next, we performed an azoxymethane (AOM)-induced two-stage carcinogenesis study. After injection of 6-week-old male F344 rats (n=30/group) once a week for 3 weeks, the animals received 2-tDCB at concentrations of 0, 10, 50 and 250 ppm in a powder diet for 25 weeks. The incidences of colon tumors for the 2-tDCB dosages were 34%, 45%, 40% and 37%, respectively, and were not statistically significant. These data suggest that 2-tDCB shows no toxic or tumor-modifying effects under the present conditions, and that the no-observed-adverse-effect level for 2-tDCB is 300 ppm in both sexes, equivalent to 15.5 mg/kg b.w./day in males and 16.5 mg/kg b.w./day in females.

3.
Biosci Biotechnol Biochem ; 77(9): 1984-7, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24018686

RESUMO

Gamma irradiation increased catalase activities at 0.1 kGy and decreased them at 10 kGy in Arabidopsis wild type and catalase-deficient mutants, cat3-1 and cat1 cat3. Irradiation induced DNA damage, H2O2 accumulation, and lipid peroxidation in both mutants as well as the wild type. Thus catalases might not be key enzymes protecting gamma irradiation-induced damage.


Assuntos
Arabidopsis/enzimologia , Arabidopsis/efeitos da radiação , Catalase/metabolismo , Dano ao DNA , Raios gama/efeitos adversos , Peróxido de Hidrogênio/metabolismo , Peroxidação de Lipídeos/efeitos da radiação , Arabidopsis/genética , Arabidopsis/metabolismo
4.
Biosci Biotechnol Biochem ; 77(12): 2371-7, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24317048

RESUMO

The levels of food allergens in gamma-irradiated soybean (0, 2.5, 5, 7.5, 10, 20, and 30 kGy) were investigated by immunoblotting and ELISA, using allergen-specific antibodies and patient serum. After 3 months of storage, Coomassie brilliant blue (CBB) staining indicated similar total protein profiles among the treatments, but that some proteins were degraded by irradiation at high doses. Immunoblotting with specific antibodies for major soybean allergens (ß-conglycinin, Gly m Bd 30 K, soybean trypsin inhibitor, and Gly m 4) resulted in apparent band profiles and intensities that were not significantly changed by irradiation. Competitive inhibition ELISA analyses suggested that there were no significant changes in the allergen contents, except for a decrease in the soybean trypsin inhibitor. The patient IgE binding allergenic protein patterns were not changed by irradiation up to 30 kGy. ELISA using patient serum also revealed that the IgE reactivity to the irradiated soybean extract did not increase from the level of the control, but that the reactivity to some patient serum IgE was significantly decreased by irradiation.


Assuntos
Alérgenos/metabolismo , Raios gama , Glycine max/imunologia , Glycine max/efeitos da radiação , Alérgenos/análise , Alérgenos/imunologia , Especificidade de Anticorpos , Relação Dose-Resposta à Radiação , Humanos , Imunoglobulina E/sangue , Imunoglobulina E/imunologia , Proteínas de Plantas/imunologia , Proteínas de Plantas/metabolismo , Glycine max/metabolismo
5.
Apoptosis ; 17(6): 636-45, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22311471

RESUMO

The irradiation of fat-containing food forms 2-dodecylcyclobutanone (2-DCB) from palmitic acid (PA). In this study, we investigated whether 2-DCB and PA induce apoptosis in human lymphoma U937 cells. We found that cell viability decreased by 2-DCB and apoptosis was induced by 2-DCB and PA. 2-DCB and PA significantly enhanced the formation of intracellular reactive oxygen species (ROS). Apoptosis induced by 2-DCB and PA was strongly prevented by an antioxidant, N-acetyl-L: -cysteine. The treatment with 2-DCB and PA resulted in the loss of mitochondrial membrane potential, and Fas, caspase-8 and caspase-3 activation. Pretreatment with a pan-caspase inhibitor (z-VAD) significantly inhibited apoptosis induced by 2-DCB and PA. Moreover, 2-DCB and PA also induced Bax up-regulation, the reduction in Bcl-2 expression level, Bid cleavage and the release of cytochrome c from the mitochondria to the cytosol. In addition, an increase in intracellular Ca(2+) concentration ([Ca(2+)](i)) was observed after the treatment with 2-DCB and PA. Our results indicated that intracellular ROS generation, the modulation of the Fas-mitochondrion-caspase-dependent pathway and the increase in [Ca(2+)](i) involved in apoptosis are induced by 2-DCB and PA in U937 cells.


Assuntos
Apoptose/efeitos dos fármacos , Ciclobutanos/toxicidade , Irradiação de Alimentos/efeitos adversos , Ácido Palmítico/química , Cálcio/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Citocromos c/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Mitocôndrias/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Células U937 , Proteína X Associada a bcl-2/genética , Proteína X Associada a bcl-2/metabolismo
6.
Mutat Res ; 741(1-2): 95-100, 2012 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-22142832

RESUMO

The gamma radiation-induced DNA damage in adult maize weevils, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), was assessed using single-cell electrophoresis (comet assay). Analysis of DNA damage following 0.5 and 1.0 kGy of gamma radiation was performed using cells from 1- and 15-day-old adults. Gamma-irradiated adults from both age groups showed typical DNA fragmentation, whereas cells from non-irradiated adults showed more intact DNA than young S. zeamais. Investigations using the comet assay showed that tail length, % tail DNA and % DNA damage all increased in adults of both age groups when compared to the control insects. A maximum comet length of 227.33 µm was recorded for 15-day-old adults at 24h after irradiation with 1.0 kGy and a minimum of 50.12 µm for 1-day-old adults at 0 h after irradiation with 0.5 kGy. The percentage of DNA damage increased up to 57.31% and 68.15% for 1- and 15-day-old adults, respectively, at 24h after irradiation with 1.0 kGy, whereas only 8.58% and 12.22% DNA damage were observed in the control batches. The results also showed that percentage of DNA damage increased at 24h after irradiation compared to that at 0 h. However, further studies are needed to confirm these results.


Assuntos
Dano ao DNA , Raios gama , Gorgulhos/efeitos da radiação , Zea mays/parasitologia , Animais , Ensaio Cometa , Relação Dose-Resposta à Radiação , Sensibilidade e Especificidade , Fatores de Tempo , Gorgulhos/genética
7.
Biosci Biotechnol Biochem ; 76(5): 900-5, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22738956

RESUMO

Food irradiation is a form of food processing to extend the shelf life and reduce spoilage of food. We examined the effects of γ radiation on the fatty acid composition, lipid peroxidation level, and antioxidative activity of soybean and soybean oil which both contain a large amount of unsaturated fatty acids. Irradiation at 10 to 80 kGy under aerobic conditions did not markedly change the fatty acid composition of soybean. While 10-kGy irradiation did not markedly affect the fatty acid composition of soybean oil under either aerobic or anaerobic conditions, 40-kGy irradiation considerably altered the fatty acid composition of soybean oil under aerobic conditions, but not under anaerobic conditions. Moreover, 40-kGy irradiation produced a significant amount of trans fatty acids under aerobic conditions, but not under anaerobic conditions. Irradiating soybean oil induced lipid peroxidation and reduced the radical scavenging activity under aerobic conditions, but had no effect under anaerobic conditions. These results indicate that the fatty acid composition of soybean was not markedly affected by radiation at 10 kGy, and that anaerobic conditions reduced the degradation of soybean oil that occurred with high doses of γ radiation.


Assuntos
Irradiação de Alimentos , Glycine max/efeitos da radiação , Óleo de Soja/efeitos da radiação , Ácidos Graxos trans/análise , Aerobiose , Anaerobiose , Cromatografia Gasosa , Relação Dose-Resposta à Radiação , Raios gama , Humanos , Peroxidação de Lipídeos/efeitos da radiação , Oxigênio/química , Óleo de Soja/química , Glycine max/química
8.
Foodborne Pathog Dis ; 7(10): 1217-23, 2010 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-20618086

RESUMO

The effect of low-dose irradiation (0.75 and 1.5 kGy) in combination with acidified sodium chlorite (ASC) on the reduction of Escherichia coli O157:H7 on mung bean seeds was examined. Washing with ASC (0.2, 0.5, 0.8, and 1.2 g/L sodium chlorite and 1.0 g/L citric acid) for 2 h reduced the E. coli O157:H7 population from 5.2 to 2.3-3.3 log CFU/g, depending on the concentrations of sodium chlorite. Gamma ray irradiation at 0.75 and 1.5 kGy resulted in reductions of about 1.8 and 2.8 log CFU/g, respectively. Therefore, a single treatment with ASC washing or gamma ray irradiation at 0.75 or 1.5 kGy could not achieve the complete elimination of E. coli O157:H7 on mung bean seeds. Conversely, low-dose irradiation (0.75 and 1.5 kGy) followed by washing with ASC (0.5-1.2 g/L) reduced the population of E. coli O157:H7 to below the detection limit (<1 log CFU/g). However, E. coli O157:H7 was detected in most samples in the enrichment and germination studies. When the treatment order was reversed (ASC washing followed by low-dose irradiation), the E. coli O157:H7 population was also observed to be below the detection limit. Under this treatment, fewer samples (16.7%) were shown to be positive in the enrichment and germination studies, and complete elimination was not achieved. The germination rates of mung bean seeds were not affected by ASC washing and gamma irradiation; however, the yield and length of sprouts were decreased by gamma irradiation.


Assuntos
Cloretos/farmacologia , Escherichia coli O157/efeitos dos fármacos , Escherichia coli O157/efeitos da radiação , Fabaceae/microbiologia , Sementes/microbiologia , Contagem de Colônia Microbiana , Escherichia coli O157/isolamento & purificação , Irradiação de Alimentos/métodos , Microbiologia de Alimentos , Raios gama , Germinação/efeitos dos fármacos , Germinação/efeitos da radiação , Concentração de Íons de Hidrogênio , Phaseolus
9.
Int J Radiat Biol ; 84(10): 815-20, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18979316

RESUMO

PURPOSE: The Deoxyribonucleic Acid (DNA) Comet assay, being a quick, simple, sensitive, reliable and fairly inexpensive method for measuring DNA strand breaks, has been used to assess DNA damage caused by gamma radiation in developmental stages of maize weevil Sitophilus zeamais Motschulsky. MATERIALS AND METHODS: An analysis of DNA damage following gamma radiation ((60)Cobalt) treatments at a dose of 0.5 and 1.0 kGy (Kilo Gray) has been carried out with cells obtained from the larvae, pupae and adults of S. zeamais. RESULTS: Gamma radiation induced significant damage at DNA level in the experimental larvae, pupae and adults as manifested by increased strand breaks compared to intact cells from non-irradiated ones. Comet assay revealed that tail length and % tail DNA varied significantly for all developmental stages of S. zeamais. CONCLUSIONS: This study suggests that the comet assay would be a potentially useful tool for detecting DNA damage in insect pest control strategies due to its advantages in the requirement of small numbers of cells per sample and sensitivity in detecting low levels of DNA damage.


Assuntos
Dano ao DNA , Raios gama , Gorgulhos/genética , Gorgulhos/efeitos da radiação , Zea mays/parasitologia , Animais , Ensaio Cometa , Larva/genética , Larva/efeitos da radiação , Pupa/genética , Pupa/efeitos da radiação , Gorgulhos/crescimento & desenvolvimento
10.
J Econ Entomol ; 99(5): 1912-9, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17066830

RESUMO

The soft-electron beam (low-energy electrons) and gamma-radiation sensitivities of phosphine-resistant (PHR) and -susceptible (PHS) strains of adults lesser grain borer Rhyzopertha dominica (F.) were studied, with particular reference to DNA damage assessed using single-cell electrophoresis (comet assay). Results showed that mortality in adult R. dominica varied significantly between both PHR and PHS strains. Adults of the PHR strain were found to be more tolerant toward soft-electron and gamma radiation than adults of the PHS strain. Studies on the longevity of strains showed that mean survival time and dose rate were highly correlated with both strains and treatments. Results also showed that adults of the PHR strain lived longer than adults of PHS strain for both treatments. Radiation sensitivity indices, however, decreased as radiation dose increased in both strains. Analysis of DNA damage, after 40- and 160-Gy gamma radiation, was carried out using cells obtained from both strains. Gamma-irradiated adults of both strains showed typical DNA fragmentation, compared with cells from nonirradiated adults, which showed more intact DNA. Investigations using the comet assay showed that tail length, moment, olive-tail moment, percentage of tail DNA, and percentage of DNA damage were all greater in the PHS strain compared with the PHR strain and the control insects. Results also showed that DNA damage remained at a constant level for up to 24 h after irradiation. The results have been discussed in relation to the observed strain differences in radiation sensitivity and resistance to phosphine.


Assuntos
Besouros/efeitos da radiação , Animais , Ensaio Cometa , Dano ao DNA , Relação Dose-Resposta à Radiação , Parasitologia de Alimentos , Raios gama , Resistência a Inseticidas , Inseticidas , Fosfinas
11.
J Agric Food Chem ; 53(4): 1022-30, 2005 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-15713015

RESUMO

To reveal the signal transduction mechanism of the response to stress in the form of active oxygen species, we used a microarray system to analyze gene expression patterns 2 or 24 h after gamma-irradiation of Arabidopsis. gamma-Irradiation induces several signal transduction and metabolite genes. By analysis of cis-elements located on the promoter region of the gamma-responsive genes, we have also found several cis-elements related to various signal transduction systems. We also analyzed the pleiotropic mutant ttg1-1, which has a dramatically altered physiological response to gamma-irradiation. By comparing the gene expression patterns of wild-type (Ler) and ttg1-1 mutant plants after gamma-irradiation, we identified various TTG1-regulated gamma-response genes. Analysis of the cis-elements in the promoter region of the gamma-responsive genes also revealed that the many transcription factors interacting with TTG1 protein (WD40 protein) are related to the gamma-responsive gene expression.


Assuntos
Arabidopsis/genética , Raios gama , Expressão Gênica/efeitos da radiação , Genes de Plantas/efeitos da radiação , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas de Arabidopsis/genética , Mutação , RNA de Plantas/análise
12.
J Food Prot ; 78(3): 561-6, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25719881

RESUMO

We investigated the distribution of cesium-134 ((134)Cs) and cesium-137 ((137)Cs) during polishing and cooking of rice to obtain their processing factors (Pf) and food processing retention factors (Fr) to make the information available for an adequate understanding of radioactive Cs dynamics. Polishing brown rice resulted in a decreased radioactive Cs concentration of the polished rice, but the bran and germ (outer layers) exhibited higher concentrations than brown rice. The Pf values for 100% polished rice and outer layers ranged from 0.47 to 0.48 and 6.5 to 7.8, respectively. The Fr values for 100% polished rice and outer layers were 0.43 and 0.58 to 0.60, respectively. The distribution of radioactive Cs in polished rice and outer layers was estimated at approximately 40 and 60%, respectively. On the other hand, cooked rice showed significantly lower levels of radioactive Cs than polished rice, and transfer of radioactive Cs into wash water was observed. The Pf and Fr values for cooked rice were 0.28 and 0.65 to 0.66, respectively. From these results, we can calculate that if the radioactive Cs concentration in brown rice is 100 Bq/kg, the concentrations of Cs in polished rice and cooked rice will be 47 to 48 Bq/kg and 13 Bq/kg, respectively.


Assuntos
Radioisótopos de Césio/análise , Culinária/métodos , Manipulação de Alimentos/métodos , Oryza/química , Poluentes Radioativos do Solo/análise , Contaminação de Alimentos/prevenção & controle
13.
J Agric Food Chem ; 51(10): 2992-9, 2003 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-12720382

RESUMO

Stabilization of the levels of active oxygen species (AOS) is important to the survival of organisms. To clarify the system controlling levels of AOS in plants, this study used an electron spin resonance (ESR) method to directly measure superoxide radical (O(2)(.-)) scavenging activities in the wild-type Arabidopsis thaliana (Col and Ler ecotypes), two anthocyanin mutants (tt3 and ttg1), and an ascorbic acid mutant (vtc1). Under ordinary growth conditions, Arabidopsis contained superoxide-scavenging activity (SOSA) of approximately 300-500 SOD units/g of fresh weight. The ESR pattern indicated that most (40-50%) of this activity was due to ascorbic acid. For the analysis of SOSA under conditions of oxidative stress, synthesis of AOS was induced by gamma-irradiation. The radical scavenging activity in irradiated plants increased approximately 10-fold following an associated increase in the accumulation of ascorbic acid and anthocyanin. The accumulation of ascorbic acid and anthocyanin was suppressed by treatment with an antioxidant before irradiation and was induced by treatment with a radical-generating reagent. The contributions of ascorbic acid and anthocyanin to the total superoxide radical scavenging activity differed among ecotypes. In the Ler ecotype, ascorbic acid accumulated at twice the level of that in the Col ecotype, and induction of anthocyanin was half that in Col. To confirm the activity of ascorbic acid and anthocyanin against AOS stress, the viability of the wild type and mutants (tt2, tt3,tt5, ttg1, and vtc1) was examined after gamma-irradiation. Only the plants in which ascorbic acid and anthocyanin were induced had the ability to grow and flower.


Assuntos
Antocianinas/análise , Arabidopsis/química , Ácido Ascórbico/análise , Espécies Reativas de Oxigênio/análise , Antocianinas/metabolismo , Antioxidantes/análise , Antioxidantes/farmacologia , Arabidopsis/genética , Arabidopsis/metabolismo , Ácido Ascórbico/metabolismo , Espectroscopia de Ressonância de Spin Eletrônica , Sequestradores de Radicais Livres/análise , Raios gama , Mutação , Oxirredução , Estresse Oxidativo , Espécies Reativas de Oxigênio/metabolismo , Superóxidos/análise
14.
Food Chem ; 145: 866-73, 2014 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-24128558

RESUMO

Reactive oxygen species (ROS) are considered to be causative agents of many health problems. In spite of this, the radical-specific scavenging capacities of food samples have not been well studied. In the present work, we have developed an electron paramagnetic resonance (EPR) spin trapping method for analysis of the scavenging capacities of food samples for multiple ROS, utilising the same photolysis procedure for generating each type of radical. The optimal conditions for effective evaluation of hydroxyl, superoxide, and alkoxyl radical scavenging capacity were determined. Quantification of radical adducts was found to be highly reproducible, with variations of less than 4%. The optimised EPR spin trapping method was used to analyse the scavenging capacities of 54 different vegetable extracts for multiple radicals, and the results were compared with oxygen radical absorption capacity values. Good correlations between the two methods were observed for superoxide and alkoxyl radicals, but not for hydroxyl.


Assuntos
Sequestradores de Radicais Livres/análise , Alimento Funcional/análise , Espécies Reativas de Oxigênio/antagonistas & inibidores , Verduras/química , Álcoois/antagonistas & inibidores , Óxidos N-Cíclicos/química , Dieta/etnologia , Espectroscopia de Ressonância de Spin Eletrônica , Sequestradores de Radicais Livres/química , Frutas/química , Radical Hidroxila/antagonistas & inibidores , Indicadores e Reagentes/química , Japão , Cinética , Fotólise , Extratos Vegetais/química , Folhas de Planta/química , Raízes de Plantas/química , Reprodutibilidade dos Testes , Detecção de Spin , Superóxidos/antagonistas & inibidores
15.
Shokuhin Eiseigaku Zasshi ; 55(5): 193-204, 2014.
Artigo em Japonês | MEDLINE | ID: mdl-25743382

RESUMO

Prawn, shrimp and crabs sold in Japan are mostly imported from overseas. Detection of irradiated crustaceans is very important for quality assurance. In this study, we used ESR to detect radiation-induced radicals after irradiation of prawn, shrimp and crabs of major species. No radiation-induced radicals were detected in prawn (black tiger prawn) or shrimp (white leg shrimp). Radiation-induced radicals due to hydroxyapatite were detected in the claws of snow crab, red king crab, and swimming crab. Our results indicate that ESR measurement on the claw parts of these three species of crab can be used to determine their irradiation history.


Assuntos
Crustáceos/química , Espectroscopia de Ressonância de Spin Eletrônica/métodos , Análise de Alimentos/métodos , Irradiação de Alimentos , Radicais Livres/análise , Animais , Durapatita
16.
Appl Radiat Isot ; 87: 485-8, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24342561

RESUMO

We developed a certified reference material of brown rice to measure radioactivity from the Fukushima Daiichi Nuclear Power Plant accident. The rice was planted in the spring of 2011, just after the Fukushima accident occurred, and it was harvested in the autumn of 2011. The certified value of radioactivity concentration in the rice was 33.6 Bq kg(-1) of Cs-134 and 51.8 Bq kg(-1) of Cs-137 on August 1, 2012. The reference material is being widely distributed by the National Metrology Institute of Japan. To determine the radioactivity and its uncertainties in the brown rice, we employed gamma-ray spectrometry with a high-purity germanium detector and Monte Carlo simulation.


Assuntos
Acidente Nuclear de Fukushima , Oryza , Monitoramento de Radiação/métodos , Poluentes Radioativos/análise , Japão , Padrões de Referência
17.
Artigo em Inglês | MEDLINE | ID: mdl-25344170

RESUMO

The DNA-damaging and tumour-promoting effects of two 2-alkylcyclobutanones (2-ACBs), which are found in irradiated fat-containing foods, were investigated by use of the comet assay and in an azoxymethane (AOM)-induced colon-carcinogenesis study in rats, respectively. We conducted genotoxicity tests of 2-dodecylcyclobutanone (2-dDCB) and 2-tetradecylcyclobutanone (2-tDCB) according to the test guidelines for chemicals or drugs. In addition, a cell-transformation assay with Bhas 42 cells was performed to investigate their promoting potential in vitro. The Salmonella typhimurium mutagenicity assay (Ames test), conducted with five tester strains, revealed that neither 2-dDCB nor 2-tDCB possessed mutagenic activity. Moreover, both in the in vitro chromosomal aberration test on CHL/IU cells and the in vivo bone-marrow micronucleus test where mice were given 2-dDCB and 2-tDCB (orally, up to 2000 mg/kg bw/day), we did not detect any clastogenic effects. Furthermore, DNA strand-breaks were not detected in the in vitro comet assay with CHL/IU cells, and DNA adducts derived from 2-dDCB and 2-tDCB were not detected in the colon tissues of the mice used for the micronucleus tests, in rats from a repeated dose 90-day oral toxicity test (0.03% 2-tDCB in the diet), or in rats from the AOM-induced carcinogenesis study (0.025% 2-tDCB in the diet). An in vitro tumour-promotion assay with Bhas 42 cells revealed that the number of transformed foci increased significantly following treatment of cells in the stationary phase with 2-dDCB or 2-tDCB for 10 days. Our results indicate that neither 2-dDCB nor 2-tDCB were genotoxic chemicals. However, they exhibited promoting activity, at least in vitro, when Bhas 42 cells were continuously exposed to these chemicals at toxic doses.


Assuntos
Ciclobutanos/toxicidade , Dano ao DNA/efeitos dos fármacos , Ácidos Graxos/química , Animais , Azoximetano/toxicidade , Carcinógenos/toxicidade , Linhagem Celular , Aberrações Cromossômicas/efeitos dos fármacos , Colo/efeitos dos fármacos , Colo/patologia , Ensaio Cometa , Cricetinae , Relação Dose-Resposta a Droga , Feminino , Irradiação de Alimentos , Masculino , Camundongos , Camundongos Endogâmicos ICR , Testes para Micronúcleos , Testes de Mutagenicidade , Mutagênicos/toxicidade , Neoplasias/induzido quimicamente , Ratos , Ratos Sprague-Dawley , Salmonella typhimurium/efeitos dos fármacos
18.
J Food Prot ; 76(6): 1021-6, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23726198

RESUMO

We investigated the fate of radioactive cesium ((134)Cs plus (137)Cs) during the production of tofu, natto, and nimame (boiled soybean) from a contaminated Japanese soybean cultivar harvested in FY2011. Tofu, natto, and nimame were made from soybean grains containing radioactive cesium (240 to 340 Bq/kg [dry weight]), and the radioactive cesium in the processed soybean foods and in by-product fractions such as okara, broth, and waste water was measured with a germanium semiconductor detector. The processing factor is the ratio of radioactive cesium concentration of a product before and after processing. For tofu, natto, nimame, and for the by-product okara, processing factors were 0.12, 0.40, 0.20, and 0.18, respectively; this suggested that these three soybean foods and okara, used mainly as an animal feed, can be considered safe for human and animal consumption according to the standard limit for radioactive cesium of soybean grains. Furthermore, the ratio of radioactive cesium concentrations in the cotyledon, hypocotyl, and seed coat portions of the soybean grain was found to be approximately 1:1:0.4.


Assuntos
Radioisótopos de Césio/análise , Qualidade de Produtos para o Consumidor , Contaminação Radioativa de Alimentos/análise , Glycine max/química , Alimentos de Soja/análise , Ração Animal , Animais , Humanos
19.
J Food Prot ; 75(10): 1823-8, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23043831

RESUMO

The fate of radioactive cesium ((134)Cs plus (137)Cs) during the milling of contaminated Japanese wheat cultivars harvested in FY2011, and during the cooking of Japanese udon noodles made from the wheat flour, was investigated. Grain samples containing various radioactive cesium concentrations (36.6 to 772 Bq/kg [dry weight]) were milled using a laboratory-scale test mill to produce eight fractions: three break flours (1B, 2B, and 3B), three reduction flours (1M, 2M, and 3M), bran, and shorts. The concentrations of radioactive cesium were found to be highest in the bran fractions of all the samples tested, with 2.3- to 2.5-fold higher values than that of the whole grain. Shorts contained radioactive cesium levels similar to that of the whole grain. In contrast, radioactive cesium concentrations in other fractions were found to be less than half the concentration in whole grain. The average processing factor (PF) value calculated for patent flour (0.401 ± 0.048), made from the mixture of 1B, 2B, 1M, and 2M for human consumption, or for low-grade flour (0.467 ± 0.045), made from the mixture of 3B and 3M, was found to be less than 0.5; whereas the average PF value (2.07 ± 0.232) for feed bran (mixture of bran and shorts), which has been used mainly as livestock feed in Japan, was over 2.0. Boiling udon noodles (made from patent flour) resulted in a substantial reduction (>70 % of initial amount) of radioactive cesium. Moreover, radioactive cesium was reduced further (<10 % of the initial amount) in the subsequent rinsing process, and the PF value of boiled noodles was recorded as 0.194. These results demonstrated that patent flour containing radioactive cesium can be made safe for human consumption by adopting the standard limit for radioactive cesium in wheat grain and that radioactive cesium in udon noodles is substantially reduced by cooking.


Assuntos
Radioisótopos de Césio/análise , Contaminação de Alimentos/análise , Manipulação de Alimentos/métodos , Triticum/química , Qualidade de Produtos para o Consumidor , Culinária/métodos , Terremotos , Farinha/análise , Humanos , Japão , Reatores Nucleares , Liberação Nociva de Radioativos , Poluentes Radioativos do Solo/análise , Poluentes Radioativos do Solo/metabolismo
20.
Shokuhin Eiseigaku Zasshi ; 52(1): 18-23, 2011.
Artigo em Japonês | MEDLINE | ID: mdl-21383529

RESUMO

The thermoluminescence (TL) method using X-rays was investigated for the purpose of detection of irradiated food, and the method was validated at a single laboratory level. A small X-ray irradiator was developed as an alternative radiation source for normalization, and X-ray irradiation conditions equivalent to gamma-ray irradiation from (60)Co were established. Gamma-ray irradiated spices were used for the method validation. The detection limits (MDL) and lower limit of integrated TL intensities (MDL×10) for the spices were checked and the separation of silicate minerals from the spices was confirmed to be sufficient for TL analysis. There was no significant difference in TL glow ratio obtained using two sets of X-ray irradiation equipment including the newly developed equipment. Repeatability and intermediate precision showed no influence of analysts, X-ray irradiation equipments, or measurement days on the TL ratios. From these results, this detection method was validated in a single laboratory.


Assuntos
Irradiação de Alimentos , Medições Luminescentes/métodos , Raios gama , Medições Luminescentes/instrumentação , Especiarias , Raios X
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA