Target specific post-harvest treatment by gamma radiation for the microbial safety of dried Melissa officinalis and Aloysia citrodora

This study aimed to assess a specific gamma radiation dose to be applied as a post-harvest process to guarantee the microbial safety of two medicinal plants, Melissa officinalis and Aloysia citrodora. Dried plants treated with gamma radiation indicated that a dose of 5 kGy could be applied as a post-harvest treatment process of M. officinalis and A. citrodora, assuring the microbial safety of dried medicinal plants and lowering the potentiality of deleterious effects on plants’ quality attributes. This will enhance the safety and quality of the dried plants to be used as raw materials in industrial applications.The authors are grateful to project PRODER nº 53515, AROMAP, for financial support of the work. The authors thank to “MaisErvas - Aromáticas e Medicinais” company for supplying the samples. C2TN/ IST authors gratefully acknowledge the FCT support through the RECI/AAG-TEC/0400/2012 and UID/Multi/04349/2013 projects.info:eu-repo/semantics/publishedVersio

Gamma irradiation in ochratoxin A control

ICFC 2017 - International Conference on Food Contaminants (Book of Abstracts)Ochratoxin A (OTA) is one of the main mycotoxins found in food. Gamma radiation is used for preserving foods since it inactivates pathogens. The effect of irradiation on mycotoxins has been studied but results are contradictory. The different matrices and conditions used by several authors may have influenced reported results. The aim of this work was to study the effects of gamma radiation in OTA in order to evaluate its applicability in foods. OTA was irradiated in its dry form, in aqueous and in methanolic solutions to evaluate the water role in OTA irradiation. Then, OTA contaminated food matrices, such as wheat flour, grape juice and wine, were irradiated.In aqueous solutions, high degradation of OTA (≥90%) was obtained with gamma radiation doses as low as 2.5kGy. However, in dried samples, OTA was found extremely resistant to radiation doses of up to 10kGy. In this case, water was a determinant factor for the effectiveness of irradiation process. In the assays with food matrices, radiation doses greater than 10kGy were needed to achieve higher reductions of OTA, being eliminated just 24%. It was also observed that OTA elimination was higher in wheat flour with higher moisture contents but the elimination of OTA in grape juice and wine were not higher than those observed in wheat flour. It is concluded that OTA is very sensitive to irradiation in water solutions but resistant in its dry form and in food matrices. Due to the low elimination percentage observed, it can be considered that gamma radiation is not a suitable technology for the elimination of OTA from foods.Thalita Calado and Luís Abrunhosa received support by grants SFRH/BD/79364/2011 and UMINHO/BPD/51/2015 from FCT, respectively. CEB gratefully acknowledge FCT support through projects UID/BIO/04469/2013, NORTE-01-0145-FEDER-000004, and RECI/BBB-EBI/0179/2012. The C2TN/IST authors gratefully acknowledge their FCT support through projects RECI/AAG-TEC/0400/2012 and UID/Multi/04349/2013.info:eu-repo/semantics/publishedVersio

Aflatoxins detoxification by gamma irradiation

[Excerpt] Mycotoxins are secondary toxic metabolites of filamentous fungi. Aflatoxins (AFs) are produced to Aspergillus species such as A. flavus and A. parasiticus. These fungi are ubiquitous in nature and usually found on agricultural commodities. Therefore, AFs are encountered in many important foodstuff, including wheat, rice, maize, peanuts, sorghum, pearl millet, spices, oilseeds, tree nuts and milk. Due to the high toxicity of AFs, many methods have been studied to reduce or eliminate these mycotoxins from food and feed. Gamma irradiation is one technology that has been investigated with promising results. The aims of this study were (I) to study the effect of gamma radiation on aflatoxin B1, aflatoxin B2, aflatoxin G1 and aflatoxin G2 (II) to evaluate the effect of the presence of water on AFs degradation during the irradiation process; and (IV) to evaluate the cytotoxicity of radiolytic products formed. (...

Castanea sativa shells and fruits: Compositional analysis by proton induced X-ray emission

Chestnut fruits, from Castanea sativa Miller species, have been previously characterized mainly to study the nutritional and biochemical parameters, with mineral contents receiving less attention from the researchers, although these minerals are essential for several mechanisms in human body. In this study, a detailed elemental compositional analysis was performed using Proton Induced X-ray Emission (PIXE) to characterize two varieties of Castanea sativa Miller chestnuts (Longal and Judia). This study comprises the composition of the outer shells (pericarp), inner shells (episperm) and the edible fruits. From our knowledge, this is the first time that the presence of up to 20 elements on the shells and the fruits are reported. Furthermore, by PIXE it was possible to quantify them, allowing significant improvements in the assessment of chestnuts composition. Essential and nonessential elements were quantified on a food item that is used mainly for human consumption but it is also incorporated in animal feeding.Authors acknowledge R. Pinheiro for sample preparation. This work was developed within the Coordinated Research Project D61024 ‘‘Development of New Applications of Machine Generated Food Irradiation Technologies’’ financed by the International Atomic Energy Agency (IAEA). IST authors gratefully acknowledge the FCT (Fundação para a Ciência e a Tecnologia) support through the UID/Multi/04349/ 2013 and UID/FIS/50010/2013 projects.info:eu-repo/semantics/publishedVersio

Ionizing radiation for food preservation processing: less or in excess?

The industrial use of ionizing radiations, such as gamma and electron beam (e-beam) radiation, is regulated and authorized by international organizations (EU, EFSA, IAEA, FAO, WHO) for several purposes: medical devices sterilization, materials modification, heritage preservation and food decontamination. However, there is mistrust among the general public regarding food irradiation due to the wrong association with an induced radioactivity on the product. Therefore, several obstacles have to be overcome in order to promote food irradiation as a safe and useful application of ionizing radiations. The increasing demand for safe and healthy food is another issue that could help to promote the use of these technologies. In Europe, the preservation of food by irradiation is strongly regulated but is still not very popular, in spite of several food safety issues, such as pathogens contamination or insects’ infestation that could be easily solved by an environment friendly technology, without the use of chemical fumigants. We will present briefly the recent state-of-art of food irradiation research in Portugal, selecting the main results of three collaborative projects funded by national and international agencies, regarding the effects of gamma radiation on physical and chemical parameters of selected materials: fruits, vegetables and mushrooms, toward the objective to keep the focus on this valuable tool for food processing.To the Projects/Agencies that supported this research: Portuguese Government and E.U. funds: PRODER/FEADER/EU (AROMAP Project); Foundation for Science and Technology (FCT, Portugal) for financial support to CIMO (PEst-OE/AGR/UI0690/2014), and C2TN (RECI/AAG-TEC/0400/2012 and UID/Multi/04349/2013 projects); International Atomic Energy Agency (IAEA) Coordinated Research Project CRP-D6-RC-1163.2 and IAEA Research contract 19220.info:eu-repo/semantics/publishedVersio

Gamma irradiation effects on microbial inactivation and antioxidant activity of Melissa officinalis

Many herbal products are traditionally being used as medicines and nutraceuticals in different regions of the world (Kumar et al., 2010). This increased consumption of natural products has become a public health problem. The concern in the safety of these products is due, in part, to the possible presence of pathogenic bacteria and fungi producing mycotoxins (Prado et al., 2009). The medicinal plant, also known as lemon balm, analysed in the present study is used in traditional medicine to treat or to relieve nervous disturbance of sleep and functional gastrointestinal disorders although there are a great variety of phytopharmaceutical preparations containing this plant or its extracts (Kennedy et al., 2002; López et al., 2009). Consequently the evaluation of the hygienic quality of medicinal plants, as well the use of decontamination methods are significant steps towards the consumer safety and therapeutical efficiency (Soriani et al., 2005). The obtained results suggested that the gamma irradiation treatment could be advantageous in improving microbial safety of M. officinalis with the potential added-benefit of increasing its antioxidant content. The effect of higher irradiation doses on M. officinalis will be further investigated, in an attempt to augment the reduction of the microbial population."MaisErvas - Aromáticas e Medicinais" company for providing the samples

Food irradiation as a key to reduce food waste and guarantee food safety

Food waste is being in the focus of recent global policies, to tackle food scarcity and to overcome “nutritional poverty” in several countries. Otherwise, a global food market is being the key to make available several products to different populations. These vectors for food policy must be supported by several orientations, to attain their final objective: better and enough food for the world population. For that, different post-harvest processing technologies are making their fundamental contribute. Among that, the preservation of food by irradiation, a physical process that does not use chemicals, is making its way in several countries, to accept imported or exported products without pests (insects), without foodborne pathogens, and also to extend the shelf life of processed products, stopping enzymatic degradation and reducing microorganisms that contribute for food spoilage. We have been studying the effects of gamma and e-beam radiation for food preservation of several Mediterranean products, including chestnuts, mushrooms and aromatic plants, berries and tomatoes, using an experimental gamma chamber with 60Co sources and an electron accelerator with the maximum energy of 10 MeV. And here we present these technologies, their limitations and advantages, the effects on relevant properties of food (e.g. color, texture, nutritional parameters), and question why food preservation by irradiation is underused, since its first use has more than 100 years and its first industrial application has more than 50 years.FCT (Portugal), FEDER PT2020 (UID/AGR/00690/2019), C2TN (UID/Multi/04349/2013), IAEA CRP D61024.info:eu-repo/semantics/publishedVersio

Descontaminação e conservação de plantas aromáticas e medicinais por irradiação

Devido às contaminações a que as plantas são expostas e tendo em conta as exigências de segurança e qualidade por parte das indústrias alimentar e farmacêutica, é indispensável o uso de processos que garantam a segurança microbiológica do material processado, sem por em causa as suas principais características.ProDer nº 5315 - AROMA

Gamma radiation effects on microbial inactivation of two medicinal plants

The consumption of natural products has become a public health problem, since these medicinal teas are prepared using natural plants without an effective hygienic and sanitary control. The aim of this study was to assess the effects of gamma radiation, on the microbial burden of two medicinal plants: Melissa officinalis and Lippia citriodora. Dried samples of the two plants were irradiated at a Co-60 experimental equipment. The applied gamma radiation doses were 1, 3, and 5 kGy at a dose rate of 1.34 kGy/h. Non-irradiated samples followed all the experiments. Bacterial and fungal counts were assessed before and after irradiation by membrane filtration method. Challenging tests with Escherichia coli were performed in order to evaluate the disinfection efficiency of gamma radiation treatment. Characterization of M. officinalis and L. citriadora microbiota indicated an average bioburden value of 102 CFU/g. The inactivation studies of the bacterial mesophilic population of both dried plants pointed out to a one log reduction of microbial load after irradiation at 5 kGy. Regarding the fungal population, the initial load of 30 CFU/g was only reduced by 0.5 log by an irradiation dose of 5 kGy. The dynamics with radiation doses of plants microbial population’s phenotypes indicated the prevalence of gram-positive rods for M. officinalis before and after irradiation, and the increase of the frequency of gram-negative rods with irradiation for L. citriadora. Among fungal population of both plants, Mucor, Neoscytalidium, Aspergillus and Alternaria were the most isolated genera. The results obtained in the challenging tests with E. coli on plants pointed out to an inactivation efficiency of 99.5% and 99.9% to a dose of 2 kGy, for M.officinalis and L. citriadora, respectively. The gamma radiation treatment can be a significant tool for the microbial control in medicinal plants.The authors are grateful to project PRODER nº 53515, AROMAP, for financial support of the work. The authors thank to "MaisErvas - Aromáticas e Medicinais" company for supplying the samples. The authors are grateful to FCT (RECI/AAGTEC/ 0400/2012) for financial support

Oxidation of clofibric acid in aqueous solution using a non-thermal plasma discharge or gamma radiation

In this work, we study degradation of clofibric acid (CFA) in aqueous solution using either ionizing radiation from a $^{60}$Co source or a non-thermal plasma produced by discharges in the air above the solution. The results obtained with the two technologies are compared in terms of effectiveness of CFA degradation and its by-products. In both cases the CFA degradation follows a quasi-exponential decay in time well modelled by a kinetic scheme which considers the competition between CFA and all reaction intermediates for the reactive species generated in solution as well as the amount of the end product formed. A new degradation law is deduced to explain the results. Although the end-product CO$_2$ was detected and the CFA conversion found to be very high under the studied conditions, HPLC analysis reveals several degradation intermediates still bearing the aromatic ring with the chlorine substituent. The extent of mineralization is rather limited. The energy yield is found to be higher in the gamma radiation experiments.Comment: 25 pages, 7 figure