Electron Beam Susceptibility of Enteric Viruses and Surrogate Organisms on Fruit, Seed and Spice Matrices.

The objective of this study was to use high-energy electron beam (HEEB) treatments to find surrogate microorganisms for enteric viruses and to use the selected surrogates as proof of concept to investigate low-energy electron beam (LEEB) treatments for enteric virus inactivation at industrial scale on frozen blueberries. Six food matrices inoculated with HAV (hepatitis A virus), MNV S99 (murine norovirus), bacteriophages MS2 and Qß, and Geobacillus stearothermophilus spores were treated with HEEB at 10 MeV using 4, 8 and 16 kGy doses. G. stearothermophilus spores showed the highest inactivation on all matrices except on raisins, with a dose-dependent effect. HAV reached the maximum measurable log10 reduction (> 3.2 log10) when treated at 16 kGy on raisins. MNV showed the highest resistance of all tested microorganisms, independent of the dose, except on frozen blueberries. On frozen blueberries, freeze-dried raspberries, sesame seeds and black peppercorns, HAV showed a mean inactivation level in between those of MS2 and G. stearothermophilus. Based on this, we selected both surrogate organisms as first approximation to estimate HAV inactivation on frozen blueberries during LEEB treatment at 250 keV using 16 kGy. Reductions of 3.1 and 1.3 log10 were measured for G. stearothermophilus spores and MS2, respectively, suggesting that a minimum reduction of 1.4 log10 can be expected for HAV under the same conditions.

Various approaches in EPR identification of gamma-irradiated plant foodstuffs: A review.

Irradiation of food in the world is becoming a preferred method for their sterilization and extending their shelf life. For the purpose of trade with regard to the rights of consumers is necessary marking of irradiated foodstuffs, and the use of appropriate methods for unambiguous identification of radiation treatment. One-third of the current standards of the European Union to identify irradiated foods use the method of the Electron Paramagnetic Resonance (EPR) spectroscopy. On the other hand the current standards for irradiated foods of plant origin have some weaknesses that led to the development of new methodologies for the identification of irradiated food. New approaches for EPR identification of radiation treatment of herbs and spices when the specific signal is absent or disappeared after irradiation are discussed. Direct EPR measurements of dried fruits and vegetables and different pretreatments for fresh samples are reviewed.

Identification of irradiated foodstuffs using ESR microwave saturation.

This study aims primarily to investigate the usage of differences in microwave (MW) saturation behaviour of food samples for identification of radiation treatment. Twenty different samples (dry plant, herbal, spice etc.) which do not have radiation specific satellite ESR signal were especially selected. It is not possible to detect radiation treatment on these samples by European standard (EN 1787, 2000). MW saturation studies were performed on all samples in the range of 0.01-160mW. Our experimental results demonstrate that radiation identification can be possible for ten samples and cannot be possible for the other ten samples by performing the MW saturation studies.

Pilot-scale radio frequency pasteurisation of chili powder: heating uniformity and heating model.

BACKGROUND: Microbial contamination is a vital obstacle needed to overcome for food safety of condiments. Radio frequency (RF) pasteurisation is a new technology to solve this obstacle. Temperature distribution and heating uniformity of sample, which are influenced by different factors, are the most important things affecting the nutritional ingredients and microbial safety of sample in the process of RF pasteurisation. This study demonstrated the location of cold spot in chili powder by analysing temperature distribution in horizontal and vertical direction. The related models were established and the accuracy was verified. RESULTS: Cold spot located on the centre of sample surface in the process of RF pasteurisation. The averaged temperature of sample increased linearly. The uniformity index decreased as the averaged temperature increased. Both the correlation coefficient of two equations were greater than 0.91. The error value of heating rate and heating uniformity index was 0.54% and 0.75% between the measured value and predicted value. CONCLUSION: Electric field was not uniformly distributed between RF parallel-plate electrodes in the RF pasteurisation of chili powder. The heating models were reliable to predict experiment results with high precision and accuracy. © 2015 Society of Chemical Industry.

Photostimulated luminescence detection and radiation effects on cinnamon (Cinnamomum zeylanicum) spice.

The increase of disease borne pathogens in foods has promoted the use of new technologies in order to eliminate these pathogen microorganisms and extend the shelf-life of the foodstuffs. In particular, Cinnamon (Cinnamomum zeylanicum) contains an important number of pathogen microorganisms and it is frequently sterilized by gamma radiation. However, it is important to develop the detection methods for irradiated food in order to keep the dose control and also to analyze the radiation effects in their chemical property. This work reports (i) the photostimulated luminescence (PSL) detection of irradiated cinnamon and thermoluminescence (TL) detection of the inorganic polymineral fraction separated from this spice, and (ii) the proximate chemical analysis carried out on fat, protein and dietetic fiber contents. The detection limits using the PSL and TL methods were 500 Gy and 10 Gy, respectively, and the fat content was increased significantly with the gamma dose that could be related to the lipid oxidation in the cinnamon.

Alcoholic extraction enables EPR analysis to characterize radiation-induced cellulosic signals in spices.

Different spices such as turmeric, oregano, and cinnamon were γ-irradiated at 1 and 10 kGy. The electron paramagnetic resonance (EPR) spectra of the nonirradiated samples were characterized by a single central signal (g = 2.006), the intensity of which was significantly enhanced upon irradiation. The EPR spectra of the irradiated spice samples were characterized by an additional triplet signal at g = 2.006 with a hyperfine coupling constant of 3 mT, associated with the cellulose radical. EPR analysis on various sample pretreatments in the irradiated spice samples demonstrated that the spectral features of the cellulose radical varied on the basis of the pretreatment protocol. Alcoholic extraction pretreatment produced considerable improvements of the EPR signals of the irradiated spice samples relative to the conventional oven and freeze-drying techniques. The alcoholic extraction process is therefore proposed as the most suitable sample pretreatment for unambiguous detection of irradiated spices by EPR spectroscopy.

Combined effects of gamma-irradiation and modified atmosphere packaging on quality of some spices.

Thyme (Thymus vidgaris L.), rosemary (Rosmarinus officinalis L.), black pepper (Piper nigrum L.) and cumin (Cuminum cyminum L.) in ground form were packaged in either air or 100% N2 and γ-irradiated at 3 different irradiation levels (7kGy, 12kGy, 17kGy). Total viable bacterial count, yeast and mould count, colour, essential oil yield and essential oil composition were determined. Microbial load was not detectable after 12kGy irradiation of all samples. Irradiation resulted in significant changes in colour values of rosemary and black pepper. The discolouration of the irradiated black pepper was lower in modified atmosphere packaging (MAP) compared to air packaging. Essential oil yield of irradiated black pepper and cumin was lower in air packaging compared to MAP. Gamma-irradiation generally decreased monoterpenes and increased oxygenated compounds, but the effect was lower in MAP. Overall, spices should be irradiated under an O2-free atmosphere to minimise quality deterioration.

Thermoluminescence study of polyminerals extracted from clove and marjoram for detection purposes.

Food irradiation is a widely employed technology for food treatment. Since in several countries no regulations prevail, it is difficult to detect whether food has been irradiated or not. Among different analytical methods the study of the thermoluminescent (TL) emission of polymineral extracted from food is one of the most useful physical identification method. The aim of this work is to analyze the TL properties of inorganic polyminerals extracted from commercial clove (Syzygium aromaticum L.) and marjoram (Origanum majorana L.) spices exposed to (60)Co gamma radiation for detection purposes. The feasibility of using the TL method for irradiated food detection and absorbed dose determination is assessed.

Identification of a gamma-irradiated ingredient (garlic powder) in Korean barbeque sauce by thermoluminescence analysis.

UNLABELLED: Thermoluminescence (TL) analysis was applied to identify gamma-irradiated garlic powder in Korean barbeque sauce before and after pasteurization (85 °C, 30 min), when blended in different ratios (1%, 3%, and 5%). The sauce sample with nonirradiated garlic powder gave a background glow curve. However, the sample blended with irradiated ingredient (1 and 10 kGy) showed typical TL glow curves at temperatures of 150 to 200 °C. The identification properties of sauce samples were more influenced by blending ratios than by irradiation doses, showing that 3% and 5% added samples produced glow curves at 150 to 250 °C. After pasteurization of the samples containing the irradiated ingredient, TL glow intensity decreased but did not change its shape or temperature range. As a result, the pasteurization of Barbeque sauces containing irradiated ingredients had reduced TL glow intensity, but the shape and temperature range of glow curve were still able to provide information required for confirming irradiation treatment. PRACTICAL APPLICATION: To monitor the irradiated food in international market, thermoluminescence (TL) analysis is considered most promising identification technique because of its sensitivity and long-term stability. In this study the applicability of TL analysis to detect an irradiated ingredient (garlic powder) added in low quantity to a food matrix (sauce) was investigated. The effect of processing (pasteurization) on TL results was also evaluated.

Post-irradiation changes of the volatile oil constituents of Monodora myristica (Gaertn) Dunal.

Volatile oil rich spices cannot be sterilised by pasteurisation because of the presence of thermal-sensitive components. In this article, we report the effect of irradiation on the volatile constituents of Monodora myristica. The samples were irradiated at ambient conditions at dose levels of 0 and 15 kGy using a linear accelerator at a dose rate of approximately 10(7) Gy s(-1). The volatile oil was extracted via headspace analysis and the quantification carried out with a HP-5MS fused silica column. Twenty-three constituents were identified with alpha-phellandrene as the major constituent (53%). Electron-beam irradiation of M. myristica did not significantly affect the volatile constituent profile at 15 kGy. Except alpha-thujene, which was increased from 7.18% to 16.76%, the most affected constituents were those that constitute less than 0.10% of the oil. Irradiation could be an effective way for decontamination of M. myristica.

A practical and transferable methodology for dose estimation in irradiated spices, based on thermoluminescence dosimetry.

The thermoluminescence technique is recommended by the European Committee for Standardization for the detection of irradiated food containing silicates as contaminants. In this work, the applicability of the thermoluminescence technique as a quantitative method to assess the original dose in irradiated oregano was studied; the additive-dose method was used, with reirradiation doses up to 600 Gy. The proposed new procedure allows to clearly discriminate irradiated from unirradiated samples, even after one year storage, and it gives an acceptable estimation of the original dose; the overall modified procedure requires only one day to be completed.

Impact of gamma-irradiation on the antioxidative properties of sage, thyme, and oregano.

Ionizing radiation is known to stimulate the generation of oxygen radicals which destabilize organic molecules resulting in a decrease of the system's antioxidant potential. The Salmonella typhimurium (TA102) reverse mutation assay, co-incubated with t-BOOH and H(2)O(2), was used to assess the effects of gamma-irradiation (dose: 10kGy) on the antioxidant properties of sage, thyme, and oregano in chloroform and methanol extracts as well as in their mixture. In addition, measurements of the trolox equivalent antioxidative capacity (TEAC), total polyphenol content (TPC), and tocopherol equivalent (TE) were performed. For the methanol and mixed extracts, antioxidative properties in the S. typhimurium reverse mutation assay were only found when using an exogenous metabolic activation system. Generally, the greatest inhibition of mutagenicity was observed in the chloroform fractions of irradiated and of non-irradiated herbs. The relative antioxidant activities for the different herbs were as follows: TA102/t-BOOH, TEAC, TPC: thyme approximately oregano>sage. TA102/H(2)O(2): thyme approximately oregano approximately sage. TE: sage>thyme>oregano. For the majority of the investigated samples the impact of irradiation was insignificant. Therefore, gamma-irradiation at the doses tested seems to have little, if any, effect on the antioxidative capacity of the tested herbs.

Solvent-free microwave extraction : an innovative tool for rapid extraction of essential oil from aromatic herbs and spices.

A relatively simple apparatus is described for extracting essential oils from aromatic plant material by atmospheric solvent-free microwave extraction (SFME) without the addition of any solvent or water. Isolation and concentration of volatile compounds were performed by a single stage. The product solutions of volatile compounds were directly analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The essential oils fiom aromatic herbs (basil, crispate mint, thyme) and spices (ajowan, cumin, star anise) extracted by SFME for 30 minutes and I hour, were similar to those obtained by conventional hydro-distillation (HD)for (respectively) 4 and 8 hours. Substantially higher amounts of oxygenated compounds and lower amounts of monoterpenes hydrocarbons are present in the essential oils of the aromatic plants extracted by SFME in comparison with HD. Solvent-free microwave extraction is clearly advantageous to conventional distillation in terms of rapidity, efficiency, cleanliness, substantial saving of energy, and is environmentally friendly.

Effects of gamma-irradiation on the free radical and antioxidant contents in nine aromatic herbs and spices.

Nine spice and aromatic herb samples (i.e., basil, bird pepper, black pepper, cinnamon, nutmeg, oregano, parsley, rosemary, and sage) were gamma-irradiated at a dose of 10 kGy according to commercial practices. The effects of the disinfection treatment on the content of organic radicals and some nutrients (namely, vitamin C and carotenoids) in the samples were investigated by chromatographic and spectroscopic techniques. Irradiation resulted in a general increase of quinone radical content in all of the investigated samples, as revealed by electron paramagnetic resonance spectroscopy. The fate of these radicals after storage for 3 months was also investigated. The cellulose radical was clearly observed in a few samples. Significant losses of total ascorbate were found for black pepper, cinnamon, nutmeg, oregano, and sage, whereas a significant decrease of carotenoids content was observed for cinnamon, oregano, parsley, rosemary, bird pepper, and sage.

Chemical investigation of gamma-irradiated saffron (Crocus sativus L.).

Changes in aroma and coloring properties of saffron (Crocus sativus) after gamma-irradiation at doses of 2.5 and 5 kGy (necessary for microbial decontamination) were investigated. The volatile essential oil constituents responsible for aroma of the spice were isolated by steam distillation and then subsequently analyzed by gas chromatography/mass spectrometry (GC/MS). No significant qualitative changes were observed in these constituents upon irradiation, although a trained sensory panel could detect slight quality deterioration at a dose of 5 kGy. Carotene glucosides that impart color to the spice were isolated by solvent extraction and then subjected to thin-layer chromatography and high-performance liquid chromatography (HPLC). Fractionation of the above pigments into aglycon and glucosides was achieved by using ethyl acetate and n-butanol, respectively. Analysis of these fractions by HPLC revealed a decrease in glucosides and an increase in aglycon content in irradiated samples. The possibility of degradation of pigments during gamma irradiation is discussed.

Detection of irradiated spices by different physical techniques.

We used thermoluminescence, electron spin resonance, and viscosimetric measurements to establish whether or not a spice had been irradiated. Thermoluminescence, using the 1788 EN official protocol with an alternative method for the extraction of mineral impurities, led to proof of irradiation or proof of no treatment. Electron spin resonance led to different spectrum shapes depending on the chemical composition of the spices; ESR could only be used as proof of irradiation up to several weeks after irradiation, and only for some spices. Viscosimetric measurements carried out on spice suspensions led to a presumption of treatment (or of no treatment) and possibly to proof of irradiation.

Identification of irradiation treatment of aromatic herbs, spices and fruits by electron paramagnetic resonance and thermoluminescence.

Electron paramagnetic resonance and thermoluminescence signals induced by gamma irradiation in some herbs, spices and fruits were systematically studied in order to detect the treatment. Using European protocols the validity and effectiveness of these two techniques are compared in regard to time of storage after irradiation.

Irradiation as a method for decontaminating food. A review.

Despite substantial efforts in avoidance of contamination, an upward trend in the number of outbreaks of foodborne illnesses caused by nonsporeforming pathogenic bacteria are reported in many countries. Good hygienic practices can reduce the level of contamination but the most important pathogens cannot presently be eliminated from most farms nor is it possible to eliminate them by primary processing, particularly from those foods which are sold raw. Several decontamination methods exist but the most versatile treatment among them is the processing with ionizing radiation. Decontamination of food by ionizing radiation is a safe, efficient, environmentally clean and energy efficient process. Irradiation is particularly valuable as an endproduct decontamination procedure. Radiation treatment at doses of 2-7 kGy--depending on condition of irradiation and the food--can effectively eliminate potentially pathogenic nonsporeforming bacteria including both long-time recognized pathogens such as Salmonella and Staphylococcus aureus as well as emerging or "new" pathogens such as Campylobacter, Listeria monocytogenes or Escherichia coli O157:H7 from suspected food products without affecting sensory, nutritional and technical qualities. Candidates of radiation decontamination are mainly poultry and red meat, egg products, and fishery products. It is a unique feature of radiation decontamination that it can also be performed when the food is in a frozen state. With today's demand for high-quality convenience foods, irradiation in combination with other processes holds a promise for enhancing the safety of many minimally processed foods. Radiation decontamination of dry ingredients, herbs and enzyme preparations with doses of 3-10 kGy proved to be a viable alternative to fumigation with microbicidal gases. Radiation treatment at doses of 0.15-0.7 kGy under specific conditions appears to be feasible also for control of many foodborne parasites, thereby making infested foods safe for human consumption. Microorganisms surviving low- and medium-dose radiation treatment are more sensitive to environmental stresses or subsequent food processing treatments than the microflora of unirradiated products. Radiation treatment is an emerging technology in an increasing number of countries and more-and-more clearances on radiation decontaminated foods are issued or expected to be granted in the near future.

Degradation of the natural mutagenic compound safrole in spices by cooking and irradiation.

Safrole was determined using gas-liquid chromatography in some common spices as star anise, cumin, black pepper and ginger. Safrole concentration in these spices was 9,325, 3,432, 955 and 500 mg.kg-1, respectively. Black pepper was chosen to use in the following experiments. Using Ames-test with Salmonella TA 98 and TA 100 proved high cytotoxic effects due to pure safrole and black pepper volatile oil in both of them. The degradation of safrole was obvious after drying of the washed seeds of black pepper especially at 70 degrees C for 30 min or with sun-drying. Also, high irradiation doses (20 and 30 kGy) caused high degradation of more than 90% of the initial toxic concentration in black pepper. Whereas, microwave caused same effects at 75 s, but unfortunately, the powder was burned due to moisture absence. Boiling whole seeds or powder of black pepper during cooking for few minutes (1-5 min) were more efficient in decreasing safrole content. Finally, these results proved that the mutagenicity of some spices due to presence of safrole can be destructed during drying of the washed seeds or during cooking either with or without any additional treatment as irradiation. But irradiation of these species became more necessary for using in some food industries as milk products to get more safe for human consumption.

Current status of the EPR method to detect irradiated food.

This review gives a brief outline of the principles of the EPR detection method for irradiated foods by food type. For each food type, the scope, limitations and status of the method are given. The extensive reference list aims to include all which define the method, as well as some rarely cited works of historical importance.