Variability in the acid adaptation of ten different O157:H7 and non-O157 Escherichia coli strains in orange juice and the impact on UV radiation resistance.

This study aimed to assess the impact of adaptation of ten strains of O157:H7 and non-O157 Escherichia coli to low pH (acid shock or slow acidification) and the effects of this exposure or not on the resistance of E. coli strains to UV radiation in orange juice (pH 3.5). The acid-shocked cells were obtained through culture in tryptic soy broth (TSB) with a final pH of 4.8, which was adjusted by hydrochloric, lactic, or citric acid and subsequently inoculated in orange juice at 4 °C for 30 days. No significant differences (p > 0.05) in survival in orange juice were observed between the serotypes O157:H7 and non-O157:H7 for acid-shocked experiments. After slow acidification, where the cells were cultured in TSB supplemented with glucose 1% (TSB + G), a significant increase (p < 0.05) in survival was observed for all strains evaluated. The D-values (radiation dose (J/cm2) necessary to decrease the microbial population by 90%) were determined as the inverse of the slopes of the regressions (k) obtained by plotting log (N/N0). The results show that among the strains tested, E. coli O157:H7 (303/00) and O26:H11 were the most resistant and sensitive strains, respectively. According to our results, the method of acid adaptation contributes to increasing the UV resistance for most of the strains tested.

Immunomodulatory effect of metabolites from digested and fermented fractions from irradiated pineapple (Annanas comosus L.) snack-bars.

Phenolic compounds (PC), can modulate the immune response. UV-C irradiation, commonly used as a minimal processing method in fresh-foods to reduce the microbial load, increase shelf-life, provide a minimal processing and facilitate the release of PC. This study aimed to evaluate the effect of intestinal (IF) and fermented (FF) fractions of non-irradiated (NIPB) and irradiated (IPB) pineapple snack-bars on the production of nitric oxide (NO), interleukin 6 (IL-6), cyclooxygenase 2 (COX-2), and tumor necrosis factor-alpha (TNF-α) in mice macrophages. IF of NIPB and IPB exerted an immunomodulatory effect by promoting the production of NO (26 pg/mL) in both treatments, COX-2 (438 and 399 pg/mL), and TNF-α (778 and 802 pg/mL) for NIPB and IPB respectively. The TNF-α increased in IF of NIPB and IPB approximately 371 %, and in FF, only increased 132 %. The NO production was not different between IF and FF. COX-2 production was higher in FF.

Identification of the gamma irradiation dose applied to ground beef that reduces Shiga toxin producing Escherichia coli but has no impact on consumer acceptance.

The aims of the present study were: a) to estimate the minimal dose of gamma irradiation required to reduce 5 log CFU/g of native O157 and non-O157 Shiga toxin-producing Escherichia coli population in ground beef samples inoculated with high inoculum; b) to assess its effectiveness in samples with low inoculum and 3) to evaluate consumer acceptance. Based on the results, 1 kGy was estimated as the minimal dose of gamma irradiation required to reduce 5 log CFU/g of STEC in ground beef. However, when samples with low inoculum level were subjected to 1 kGy, 3.9% of the samples were positive for stx and eae genes after an enrichment step. Consumer acceptance analysis was carried out with samples subjected to 2.5 kGy and no significant differences were found between irradiated and control samples. Therefore, 2.5 kGy was identified as the gama irradiation dose that reduces STEC but has no impact on consumer acceptance of ground beef.

Perfil hematológico e bioquímico de roedores de laboratório alimentados com rações contendo diferentes fontes lipídicas e métodos de esterilização / Hematological and biochemical profile of laboratory rodents feeded with rations containing different lipid sources and sterilization methods

Objetivou-se com esse estudo avaliar os efeitos de diferentes métodos de esterilização e fontes de óleo (salmão e linhaça) em formulação de rações sobre os parâmetros bioquímicos e hematológicos de ratos Wistar e camundongos NIH em diferentes idades. Foram avaliados 336 animais, sendo 168 de cada biomodelo. Houve efeito significativo das fontes de óleo sobre os parâmetros bioquímicos plasmáticos em camundongos NIH e ratos Wistar (P 0,05). Conclui-se que o óleo de salmão e linhaça podem ser utilizados nas rações para camundongos NIH e ratos Wistar, independente do método de esterilização adotado.(AU)

The objective of this study was to evaluate the effects of different methods of sterilization and oil sources (salmon and flaxseed) in the formulation of diets on the biochemical and hematological parameters of Wistar rats and NIH mice at different ages. 336 animals were evaluated, 168 from each biomodel. There was a significant effect of oil sources on plasma biochemical parameters in NIH mice and Wistar rats (P < 0.05). There were no significant effects of the sterilization methods on any evaluated parameter (P > 0.05). It was concluded that salmon and linseed oil can be used in diets for NIH mice and Wistar rats, regardless of the sterilization method adopted.(AU)

Perfil hematológico e bioquímico de roedores de laboratório alimentados com rações contendo diferentes fontes lipídicas e métodos de esterilização / Hematological and biochemical profile of laboratory rodents feeded with rations containing different lipid sources and sterilization methods

Objetivou-se com esse estudo avaliar os efeitos de diferentes métodos de esterilização e fontes de óleo (salmão e linhaça) em formulação de rações sobre os parâmetros bioquímicos e hematológicos de ratos Wistar e camundongos NIH em diferentes idades. Foram avaliados 336 animais, sendo 168 de cada biomodelo. Houve efeito significativo das fontes de óleo sobre os parâmetros bioquímicos plasmáticos em camundongos NIH e ratos Wistar (P 0,05). Conclui-se que o óleo de salmão e linhaça podem ser utilizados nas rações para camundongos NIH e ratos Wistar, independente do método de esterilização adotado.

The objective of this study was to evaluate the effects of different methods of sterilization and oil sources (salmon and flaxseed) in the formulation of diets on the biochemical and hematological parameters of Wistar rats and NIH mice at different ages. 336 animals were evaluated, 168 from each biomodel. There was a significant effect of oil sources on plasma biochemical parameters in NIH mice and Wistar rats (P 0.05). It was concluded that salmon and linseed oil can be used in diets for NIH mice and Wistar rats, regardless of the sterilization method adopted.

Cold plasma processing effect on cashew nuts composition and allergenicity.

The study investigated the influence of atmospheric plasma processing on cashew nut composition as well as on its allergenicity. The cashew nuts were processed by low-pressure plasma, using glow discharge plasma (80 W and 50 kHz power supply). Anacardic acids and allergens were quantified by HPLC and immunoassay, respectively. Additionally, the overall composition was evaluated by 1H qNMR. Increases in amounts of anacardic acids (15:1, 15:2, and 15:3) and fatty acids (oleic, linoleic, palmitic and stearic) were detected after all process conditions, with 70.92% of total variance captured using 2 LVs. The total amount of anacardic acids increased from 0.7 to 1.2 µg·mg-1 of nut. The major change was observed for anacardic acid (C15:3) with an increase from 0.2 to 0.55 µg/mg of nut for the samples treated with a flow of 10 mL·min-1 and 30 min of processing. On the other hand, the amount of sucrose decreased, from 33 to 18 mg·g-1 of nut, after all processing conditions. Plasma processing of cashew nuts did not affect binding of either the rabbit anti-cashew or human cashew allergic IgE binding. Among the treatments, 10 min of plasma processing at flow rate of 30 mL·min-1 of synthetic air followed by 20 min at flow rate 5.8 mL·min-1 had the least effect on nut composition as a whole.

Effect of ultraviolet (UV-C) radiation on spores and biofilms of Alicyclobacillus spp. in industrialized orange juice.

Bacteria of the genus Alicyclobacillus pose serious quality problems for the juice processing industries that have sought effective alternatives for its control. The present study evaluated the effect of UV-C radiation on the reduction of spores and biofilm formation of Alicyclobacillus spp. on stainless steel and rubber surfaces using industrialized orange juice as a culture medium. Four reference Alicyclobacillus spp. species and different UV-C dosages were investigated. After exposed for 20 min (16.8 kJ/m2) to UV-C, the spores of Alicyclobacillus acidoterrestris, Alicyclobacillus herbarius, and Alicyclobacillus cycloheptanicus decreased drastically more of 4 log CFU/mL, with counts below the detection limit of the method (<1.7 log CFU/mL), while the Alicyclobacillus acidocaldarius spores were more sensitive to UV-C, once this spore reduction was observed within 15 min (12.6 kJ/m2). Morphological changes in the Alicyclobacillus acidoterrestris spores were observed by scanning electron microscopy. A reduction of biofilm formation was observed for all UV-C treatments, and the higher reductions (approximately 2 log CFU/mL) were found for the Alicyclobacillus acidocaldarius species after 30 min (26.2 kJ/m2), on the stainless steel and rubber surfaces. The results suggest that UV-C can be used to reduce the biofilm formation and could be a promising alternative for controlling Alicyclobacillus spp. spores in industrialized orange juice.

Synergistic effect of ultraviolet radiation and high hydrostatic pressure on texture, color, and oxidative stability of refrigerated tilapia fillets.

BACKGROUND: The isolated application of high hydrostatic pressure (HHP) and ultraviolet-C (UV-C) radiation may induce physicochemical changes, thus jeopardizing fish quality attributes during refrigerated storage, which could be minimized by the use of synergistic treatments. Therefore, this study investigated the combined effect of UV-C at 0.103 ± 0.002 J cm−2 and HHP at 220 MPa for 10 min on quality parameters of tilapia fillets stored at 4 °C for 15 days. RESULTS: HHP and UV-C+HHP showed higher myoglobin concentration, higher metmyoglobin-reducing activity, and lower a* than control and the UV-C treatment (P < 0.05), reaching 2.49, 2.58, 1.62, 1.54 mg myoglobin g−1 , 13.30, 13.81, 2.29, 2.29%, and 2.32, 2.58, 4.29, 3.98 respectively on the last day of storage. UV-C, HHP, and UV-C+HHP increased water-holding capacity and decreased the pH levels, hardness, and chewiness (P < 0.05). HHP retarded lipid oxidation and UV-C increased protein oxidation compared with control (P < 0.05), achieving 0.81 and 2.80 mg malondialdehyde per kilogram of fish tissue, and 5.50 and 4.15 nmol carbonyl per milligram of protein respectively on 15th day of the storage. CONCLUSION: Both technologies (alone or together) enhanced texture parameters and water-holding capacity. UV-C did not induce color changes and lipid oxidation, whereas HHP showed high potential to prevent meat discoloration, lipid oxidation, and protein oxidation. In addition, this combination of methods could be an alternative to prevent protein oxidation induced by UV-C.

Irradiation of reduced-sodium uncooked lamb sausage: antimicrobial efficacy and physicochemical impact.

Excess sodium in food is associated with an increased risk of noncommunicable diseases. Faced with this reality, consumers are becoming aware of the importance of eating foods with reduced sodium content. This work assesses the effects of partial replacement of NaCl by KCl on the microbiological and physicochemical characteristics of uncooked lamb sausage treated with different doses of gamma radiation. Analyses of thermotolerant coliforms, sulfite-reducing Clostridium, Salmonella sp., protein, moisture, ash, lipids, pH, water activity, and color were performed. The results showed that the formulations with reduced sodium content did not differ significantly concerning microbial growth and met the identity and quality standards considering its physicochemical characteristics. Also, irradiation is efficient as a microbiological control method, and the ± 3-kGy dose was the most effective to eliminate pathogenic bacteria present in the sausage formulation prepared with reduced sodium content, inducing less intense changes in physicochemical parameters.

The Dissipative Potential of Gamma Irradiation in Residues of Imidacloprid and Thiamethoxam in the Postharvest of Common Beans.

Gamma irradiation (60 Co) in postharvest of common beans (Phaseolus vulgaris L.), has already proven beneficial, regarding the prolongation of shelf life and physical, chemical, and organoleptic aspects of grains. However, few prior studies have investigated the effect of gamma irradiation on the dissipation of pesticides in foods, especially insecticides in beans. This study aimed to evaluate the waste dissipation of two insecticides, imidacloprid and thiamethoxam, used in the cultivation of common bean, a variety of Carioca, using gamma irradiation. Ground bean samples were spiked each insecticide in the laboratory at 3, 4, and 5 mg/kg, and were then irradiated at 0, 1, and 2 kGy per irradiator with a 60 Co source. Liquid chromatography-tandem mass spectrometry was used to quantify the insecticides. The irradiation promoted dissipation of thiamethoxam at 1 and 2 kGy doses, with the highest dissipation verified at 2 kGy. In general, at this higher dose of irradiation the reduction dissipation of thiamethoxam was 66% of the mean value found in the treatment without irradiation and ∼44% relative to the 1 kGy dose. Conversely, imidacloprid showed no effect of irradiation on waste dissipation, except in the treatment of 5 mg/kg at 2 kGy dose. From the results, it was concluded that the gamma irradiation might have applicability in dissipating thiamethoxam in real bean samples. PRACTICAL APPLICATION: Pesticide residues remaining from bean cultivation, sensitive to optimal doses of gamma irradiation, can be transformed into other less harmful or nonharmful substances, increasing the quality of the beans before the food arrives at the consumer's table. Irradiation of the grains after harvest also eliminates the need for application of other pesticides to preserve the grains during storage, as the technique is capable of eradicating deteriorating agents, such as microorganisms and insects.

Use of microbial models to evaluate the effect of UV-C light and trans-cinnamaldehyde on the native microbial load of grapefruit (Citrus × paradisi) juice.

The aim of this research was to evaluate the storage stability (5 °C), and microbial modeling, of Rubi red grapefruit (Citrus × paradisi) juice treated with ultraviolet-C (UV-C) light (0, 10 and 20 min), alone or in combination with trans-cinnamaldehyde (trans-CAH) (0, 25 and 50 µg/mL). A 32 factorial design was used and data modeled with the Weibull, Modified Gompertz and Logistic models. A response surface model was used to evaluate the effect of modeling parameters for suggesting the optimum treatment conditions. Treated and some untreated juice lasted up to 9 days without physicochemical and microbial changes. At the higher combination of UV-C light and trans-CAH, the microbial load of grapefruit juice was maintained below 100 CFU/mL up to 15 days. For mesophiles, the three predictive models indicated that the parameters n and Nmax decreased and the parameters λ and tc increased as the combination of UV-C light and trans-CAH increased. The response surface modeling of the parameters obtained by the predictive models showed acceptable correlation for mesophiles (R2 = 0.815-0.977) but not for yeasts (R2 = 0.618-0.815). The three predictive models showed that, the concentration of trans-CAH had more effect on stopping the microbial growth than the UV-C light treatment.

Construction and validation of a psychometric scale to measure awareness on consumption of irradiated foods.

Although food irradiation has been used to ensure food safety, most consumers are unaware of the basic concepts of irradiation, misinterpreting information and demonstrating a negative attitude toward food items treated with ionizing radiation. This research is aimed at developing a tool to assess the awareness on the consumption of irradiated food. The sample was composed by employees from different social classes and school levels of Brazilian universities, who reflect the end-users of the irradiated foods, representative of the views of lay consumers. The total number of respondents was 614. In order to assess the Awareness Scale on Consumption of Irradiated Foods (ASCIF), an instrument has been developed and submitted to semantic tests and judge's validation. The instrument, that included 32 items, contemplated four construct factors: concepts (6 items), awareness (10 items), labeling (7 items) and safety of Irradiated foods (9 items). The data were collected by electronic means, through the site . By using exploratory factorial analysis (EFA) 4 factors have been found. They summarize the 31 items included. These factors account for 64.32% of the variance of the items and the internal consistency of the factors has been deemed good. An Exploratory Structural Equation Modeling (ESEM) was conducted to evaluate the factor structure of the instrument. The proposed instrument has been found to meet consistency criteria as an efficient tool for indicating assessing potential challenges and opportunities for the irradiated food markets.

Avaliação físico-química e sensorial de vinho de jabuticaba submetido a tratamento de radiação gama / Physical-chemical and sensorial evaluation of jaboticaba wine subjected to gamma radiation treatment

A jabuticaba é uma fruta tropical, tipicamente brasileira, sendo originária da região centro-sul. Popularmente apreciada por suas características sensoriais in natura, mas também pela utilização em produtos processados como geleias, licores e bebidas fermentadas (SASSO; CITADIN; DANNER, 2010). Apesar da designação vinho referir- -se segundo a Lei nº 7.678, de 08 de novembro de 1988 (BRASIL, 1988) como "bebida proveniente da fermentação alcoólica de mosto de uva sã, fresca e madura", é permitido pela Portaria Nº 64, de 23 de abril de 2008 a produção de vinhos de outras frutas (BRASIL, 2008), desde que se indique o nome da fruta no rótulo após a palavra vinho, como por exemplo vinho de jabuticaba.(AU)

Detection of differentially methylated regions of irradiated fig tree selections

Fig tree (Ficus carica L.) breeding programs using conventional methods, such as directed crosses, to obtain new cultivars, are unworkable in many countries, including Brazil. Consequently, genetic breeding through mutagenesis has emerged as an important line of research that can improve this crop, and be a significant source of information about this species and assist in the implementation of propagation projects and appropriate management. The aim of this study was to verify the existence of epigenetic variability attributable to DNA methylation in irradiated fig selections when compared both to each other and to the main commercial cultivar, Roxo-de-Valinhos, which had previously used methylation-sensitive amplified polymorphism (MSAP) and DNA sequencing to detect the position of polymorphic regions, analyzable by bioinformatic tools. The sequencing of DNA, isolated from the differentially methylated sites, makes it possible to observe different patterns of methylation by sequencing the treated DNA with sodium bisulfite in the coding regions of regulatory genes active in the development, and fruit ripening stages. Furthermore, they have been found in the mitochondrial DNA of treatments which regulate the supply of energy in Adenosine triphosphate (ATP) form in plants. Closely related to their development, they justify the different phenotypes found in both fruit and plant growth that have suffered stress due to exposure to gamma radiation. Thus, future studies on gene expression in treatments have emerged as an extremely important strategy for understanding these complex regulatory systems, which may lead to the identification of genes of agricultural interest for the fig tree crop, and allow for manipulation and subsequent propagation of improved crops for commercial purposes.

Detection of differentially methylated regions of irradiated fig tree selections

Fig tree (Ficus carica L.) breeding programs using conventional methods, such as directed crosses, to obtain new cultivars, are unworkable in many countries, including Brazil. Consequently, genetic breeding through mutagenesis has emerged as an important line of research that can improve this crop, and be a significant source of information about this species and assist in the implementation of propagation projects and appropriate management. The aim of this study was to verify the existence of epigenetic variability attributable to DNA methylation in irradiated fig selections when compared both to each other and to the main commercial cultivar, Roxo-de-Valinhos, which had previously used methylation-sensitive amplified polymorphism (MSAP) and DNA sequencing to detect the position of polymorphic regions, analyzable by bioinformatic tools. The sequencing of DNA, isolated from the differentially methylated sites, makes it possible to observe different patterns of methylation by sequencing the treated DNA with sodium bisulfite in the coding regions of regulatory genes active in the development, and fruit ripening stages. Furthermore, they have been found in the mitochondrial DNA of treatments which regulate the supply of energy in Adenosine triphosphate (ATP) form in plants. Closely related to their development, they justify the different phenotypes found in both fruit and plant growth that have suffered stress due to exposure to gamma radiation. Thus, future studies on gene expression in treatments have emerged as an extremely important strategy for understanding these complex regulatory systems, which may lead to the identification of genes of agricultural interest for the fig tree crop, and allow for manipulation and subsequent propagation of improved crops for commercial purposes.(AU)

Ames Test to Detect Mutagenicity of 2-Alkylcyclobutanones: A Review.

Food irradiation is an effective and safe method for preservation and long-term storage, and it is approved for use in over 60 countries for various applications in a wide variety of food products. This process is performed by use of accelerated electron beams, X-rays, or gamma radiation (60 Co or 137 Cs). 2-Alkylcyclobutanones (2-ACBs) are the only known radiolytic products generated from foods that have fatty acids (triglycerides) and are subjected to irradiation. Since the 1990s toxicological safety studies of 2-ACBs have been conducted extensively through synthetic compounds, then and tests to determine if the compounds have any mutagenic activity are strictly necessary. The Ames test was chosen by many researchers to assess the mutagenicity of 2-ACBs. The test uses distinct bacterial cell lines Salmonella typhimurium to detect point mutations at sites guanine-cytosine (G-C) and Escherichia coli to detect point mutations at sites adenine-thymine (A-T). This bibliographic research aims to bring together all the results obtained and a comparison and cell lines used, type of plates, and solvents. This research showed that no mutagenic activity was observed in any of the cell lines and concentrations evaluated by the works of authors, so the 2-ACBs compounds showed no mutagenic substance in concentrations detectable by the Ames test.

Impact of UV-C Light on the Fatty Acid Profile and Oxidative Stability of Nile Tilapia (Oreochromis niloticus) Fillets.

The influence of different ultraviolet (UV-C) doses (0.103 and 0.305 J/cm2 ) was investigated by instrumental color parameters, pH, lipid, and protein oxidations, fatty acids (FA) composition and biogenic amines (BAs) in Nile tilapia fillets during 11 d at 4 ± 1 °C. The UV-C treatment increased (P < 0.05) a* values and protein oxidation in a dose-dependent manner, and delayed (P < 0.05) the formation of BAs over the course of the storage period. L* values and lipid oxidation were not influenced (P > 0.05) by UV-C light. Fillets treated with a low UV-C dose exhibited greater (P < 0.05) total polyunsaturated fatty acid (PUFA) than their untreated counterparts. Therefore, a low UV-C dose can be recommended in tilapia fillets as an alternative processing method to control pH and BAs, as well as improve the total PUFA amount and overall nutritional quality.

A new approach to mineralization of flaxseed (Linum usitatissimum L.) for trace element analysis by flame atomic absorption spectrometry.

A new approach to the analysis of Cu, Fe, Mn and Zn in flaxseed was developed based on infrared-assisted acid digestion. Quantitation by flame atomic absorption spectrometry yields results in agreement with those arising from aggressive total decomposition using conventional microwave-assisted (MW) digestions. A full factorial design in two levels was applied to evaluate the impact of significant variables for all elements to determine optimal experimental conditions. A desirability function revealed these to be: 2.0g sample mass, 8mL of HNO3 and 8min of heating time in the IR system. Precision better than 10% (RSD) was obtained, superior to that of a combined IR-MW approach. Sample preparation based on IR-assisted digestion provides a rapid and inexpensive alternative to other conventional techniques for the analysis of complex samples and is able to accommodate relatively large masses of sample, alleviating potential homogeneity issues as well as enhancing detection power.

Efeitos da irradiação gama sobre a estabilidade físico-química de anéis de lula congelados / Effects of gamma irradiation on the physico-chemical stability of frozen squid rings

O principal objetivo deste trabalho foi avaliar os efeitos do processo de exposição à radiação gama (césio- 137) na estabilidade físico-química de anéis de lula, Dorytheutis plei, congelados. Foram investigadas 30 amostras, separadas em três grupos, de acordo com a dose de radiação absorvida: 0 kGy (controle), 1,5 kGy e 3,0 kGy. Análises físico-químicas, de Base Voláteis Totais e pH, relevantes na determinação da qualidade do pescado, foram realizadas durante o período de seis semanas. Durante a estocagem, observou-se uma relativa estabilidade físico-química nas amostras estudadas, caracterizando um produto viável para a comercialização. Dentre as doses investigadas, 1,5 kGy mostrou-se a mais apropriada para tratamento do produto. Não houve alteração significativa da composição centesimal das amostras.

Evaluation of the effectiveness of non-irradiated and chlorine-free packaging for fresh beef preservation.

This study evaluates the potential of using non-irradiated barrier-shrink bags containing ethylene-vinyl alcohol copolymer (EVOH), polyamide (PA) and ethylene ionomer in their structures to preserve vacuum-packaged fresh beef as an alternative to traditional gamma-ray cross-linked bags containing polyvinylidene chloride (PVDC). Boneless beef rib eye roll cuts were vacuum-packed in an industrial processing plant using EVOH 44% mol, EVOH 32% mol and a control PVDC barrier shrink bags. The cuts were evaluated during storage at 0.5°C. The EVOH films presented similar performance compared to control PVDC barrier shrink bags related to bacteria growth and purge loss. Packages with EVOH 32% mol film presented better performance than control bag with respect to the meat sensorial attributes, including fewer bubbles and better adhesion. EVOH 44% mol bags presented the highest rate of colour loss. The EVOH 32% mol non-irradiated and chlorine-free film is as effective for the preservation of fresh beef as traditional PVDC-irradiated shrink bags.