Significance: The detrimental effects of ionizing radiation (IR) involve a highly orchestrated series of events that are amplified by endogenous signaling and culminating in oxidative damage to DNA, lipids, proteins, and many metabolites. Despite the global impact of IR, the molecular mechanisms underlying tissue damage reveal that many biomolecules are chemoselectively modified by IR. Recent Advances: The development of high-throughput “omics” technologies for mapping DNA and protein modifications have revolutionized the study of IR effects on biological systems. Studies in cells, tissues, and biological fluids are used to identify molecular features or biomarkers of IR exposure and response and the molecular mechanisms that regulate their expression or synthesis. Critical Issues: In this review, chemical mechanisms are described for IR-induced modifications of biomolecules along with methods for their detection. Included with the detection methods are crucial experimental considerations and cav...

/pdf/effects-of-ionizing-radiation-on-biological-molecules-mam0yv36pg.pdf

Effects of ionizing radiation on biological molecules--mechanisms of damage and emerging methods of detection.

Processed meats represent a large percentage of muscle foods consumed in the western world Various processing steps affect the physicochemical properties of the meat, compromise its nutritional components, or produce some compounds that are of health concern Hence, the impact of oxidation on human health and the aging process and the influence of diet on these harmful reactions are of growing interest Past decades have seen more focus on lipid oxidation, microbial deterioration, and pathogenicity, as well as production of carcinogenic compounds during meat processing The oxidation of protein, which is a major component in meat systems, has received less attention Protein oxidation has been defined as a covalent modification of protein induced either directly by reactive species or indirectly by reaction with secondary by-products of oxidative stress Not only are these modifications critical for technological and sensory properties of muscle foods, they may have implications on human health and safety when consumed Cooking, for example, has been observed to increase free radical generation while it also decreases the antioxidant protection systems in meat, both of which contribute to protein oxidation Many other meat processing techniques, as well as other emerging technologies, may significantly affect protein oxidation and protein overall quality This paper explores the current understanding of meat processing techniques and their possible effects on the status of protein oxidation and nutritional value, as well as their possible implications on human health

Protein Oxidation in Processed Meat: Mechanisms and Potential Implications on Human Health.

to the Microbiological Spoilage of Foods and Beverages.- Microbiological Spoilage of Dairy Products.- Microbiological Spoilage of Meat and Poultry Products.- Microbiological Spoilage of Fish and Seafood Products.- Microbiological Spoilage of Eggs and Egg Products.- Microbiological Spoilage of Fruits and Vegetables.- Microbiological Spoilage of Canned Foods.- Microbiological Spoilage of Cereal Products.- Microbiological Spoilage of Beverages.- Microbiological Spoilage of Acidified Specialty Products.- Microbiological Spoilage of High-Sugar Products.- Microbiological Spoilage of Spices, Nuts, Cocoa, and Coffee.

/pdf/compendium-of-the-microbiological-spoilage-of-foods-and-7s6wkk0blq.pdf

Compendium of the microbiological spoilage of foods and beverages

This review examines the role that oxidative stress, and protein oxidation in particular, plays in nutrition, metabolism and health of farm animals. The route by which redox homeostasis is involved in some important physiological functions and the implications of the impairment of oxidative status on animal health and diseases is also examined. Proteins have various and, at the same time, unique biological functions and their oxidation can result in structural changes and various functional modifications. Protein oxidation seems to be involved in pathological conditions such as respiratory diseases and parasitic infection; however some studies also suggest that protein oxidation plays a crucial role in the regulation of important physiological functions such as reproduction, nutrition, metabolism, lactation, gut health and neonatal physiology. As the characterization of the mechanisms by which oxidative stress may influence metabolism and health is attracting considerable scientific interest, the aim of this review is to present veterinary scientists and clinicians with various aspects of oxidative damage to proteins.

/pdf/oxidant-antioxidant-balance-in-animal-nutrition-and-health-26k0qnbez0.pdf

Oxidant/Antioxidant Balance in Animal Nutrition and Health: The Role of Protein Oxidation

The organic acids and phenolics compositions of nine wild edible mushrooms species (Suillus bellini, Tricholomopsis rutilans, Hygrophorus agathosmus, Amanita rubescens, Russula cyanoxantha, Boletus edulis, Tricholoma equestre, Suillus luteus, and Suillus granulatus) were determined by HPLC-UV and HPLC-DAD, respectively. The antioxidant potential of these species was also assessed by using the DPPH• scavenging assay. The results showed that all of the species presented a profile composed of at least five organic acids:  oxalic, citric, malic, quinic, and fumaric acids. In a general way, the pair of malic plus quinic acids were the major compounds. Only very small amounts of two phenolic compounds were found in some of the analyzed species:  p-hydroxybenzoic acid (in A. rubescens, R. cyanoxantha, and T. equestre) and quercetin (in S. luteus and S. granulatus). All of the species exhibited a concentration-dependent scavenging ability against DPPH•. T. rutilans revealed the highest antioxidant capacity. Keywo...

/pdf/contents-of-carboxylic-acids-and-two-phenolics-and-3x47aud1oa.pdf

Contents of Carboxylic Acids and Two Phenolics and Antioxidant Activity of Dried Portuguese Wild Edible Mushrooms

Grolichova M., P. Dvofiak, H. Musilova : Employing Ionizing Radiation to Enhance Food Safety ‐ a Review . Acta Vet. Brno 2004, 73: 143-149. Food irradiation has been employed to ensure food safety or food sterility, extend its shelf-life and reduce the losses due to sprouting and ripening or pests. In the Czech Republic, mainly spices, mixed spices and dried vegetable are exposed to ionizing radiation. The greatest suppliers of irradiated foodstuffs in Europe are Belgium, France and the Netherlands. In the USA, food irradiation is more common and there are also attempts to enforce irradiation not only for food safety, but also for technological purposes. Even though irradiation is a prospective technology, its application causes physical-chemical and biochemical changes that may affect nutritional adequacy and sensory characteristics of irradiated food. In this paper, the chemical changes of basic food components (proteins, saccharides, fats) are reviewed. The chemical changes result in radiolytic products whose risks are still subject of scientific research. It is expected that the main use of gamma irradiation will be treatment of diets for patients suffering from different disorders of the immune system, allergic patients or for the army and space flights. In the production of raw or heat non-processed foodstuffs, irradiation may be a critical control point (CCP). Gamma irradiation, food, legislative bases, radiation effects, nutritional adequacy The Purpose of Food Irradiation

/pdf/employing-ionizing-radiation-to-enhance-food-safety-a-review-loff3krw9d.pdf

Employing Ionizing Radiation to Enhance Food Safety - a Review

The aim of the study was to find the sources of 137Cs in wild boar food in the natural ecosystem. The main emphasis is focused on the analyses of wild boar muscles and the content of wild boar stomach. Boars weighing 20 to 100 kg were killed at two locations. The highest specific activities of muscles were measured in boars originated from the Dvorce location; the average specific activity in boars killed on 14 April 2007 and 9 March 2008 achieved 132 Bq·kg-1. Due to high fluctuation the differences between the mean values of 31 Bq·kg-1 in males and 43 Bq·kg-1 in females were not significant. Earthworms from grass fields with a specific activity of 16 Bq·kg-1, rootlets from the Sabrava location with 200 Bq·kg-1 and Elaphomyces granulatus fruiting bodies with 4,743 Bq·kg-1 and 2,858 Bq·kg-1 are the components of boar food with the 137Cs specific activities higher than that of the detection limit. Consequently, underground mushrooms probably represent the main source of radiocesium in the food chain of boars. A remarkable reduction of 137Cs specific activities in boar muscles is not expected at the post-Chernobyl radiocesium contaminated locations with the occurrence of Elaphomyces granulatus within next two decades. Sus scrofa, 137Cs, Elaphomyces granulatus, radioecology, Chernobyl, radionuclide migration, ingestion, foot The consequences of nuclear accidents can have a long-term effect on some biocenoses. It is caused by the transfer capability of some radionuclides that move from the abiotic environmental components to the biotic component and accumulate in it. One of them is the 137Cs radionuclide, i.e. the primary post-Chernobyl nuclide (with its physical half-life of about 30 years), that was shortly accompanied by 134Cs (with its physical half-life of about 2 years) after the disaster, both with the chemical behaviour similar to that of potassium (Garger et al. 2006; Rajec et al. 2009). After successive reduction of the radiocesium activity in muscles of fair game, an unexpected reversal occurred in the 1990s. After floods in the North-Eastern Moravia in June 1997, the radiocesium activity increased in the muscles of fair game (in 183 specimens examined by the State Veterinary Administration). This mainly pertained to boars and ungulate game with the exception of mountain goats. According to the State Veterinary Administration of the Czech Republic, the average activities were 61 Bq·kg-1 from 1992 to June 1997, 588 Bq·kg-1 from July 1997 to 2000, followed by reduction to the average of 101 Bq·kg-1 observed during the years 2001 and 2002. Specific activities that exceeded 1,250 Bq·kg-1 were randomly detected in boars after the flood in North-Eastern Moravia, i.e. values that exceeded the maximum permissible activity (Decree of SUJB 2002). Such values were detected in four specimens (from 1,649 to 7,510 Bq·kg-1). Resorption of radiocesium (137Cs) in the digestive tract of vertebrates is relatively high (50% and more). Resorption can reach up to 80% in ruminants whereas 100% can be reached in monogastric animals (especially carnivores). The wild boar belongs to animals whose origins of 137Cs have not been exactly explained yet. ACTA VET. BRNO 2010, 79: S85–S91; doi:10.2754/avb201079S9S085 Address for correspondence: Prof. MVDr. Petr Dvořak, CSc. Department of Biochemistry, Chemistry and Biophysics, Faculty of Veterinary Hygiene and Ecology University of Veterinary and Pharmaceutical Sciences Brno Palackeho 1-3, 612 42 Brno, Czech Republic Phone: +420 541 562 608 E-mail: dvorakp@vfu.cz http://www.vfu.cz/acta-vet/actavet.htm The importance of radiocesium exposure of human beings by ingestion of boar meat seems to be negligible due to low consumption of wild boar meat in the Czech and Slovak Republics (about 0.5 kg a year). However, the radiological risk of a critical group should not be underestimated. For example, the consumption of wild boar meat by members of hunting associations is higher by nearly two orders than that of the rest of the population, exceeding sometimes more than a half of other yearly meat consumption. Ecological halflife models (Lettner et al. 2009) can be used as valuable and effective tools to specify the countermeasures for contamination reduction or meat consumption regulation. Cooking or salting, including meat brining can take part in such countermeasures (Dvořak at al. 2008). The explanation of radiocesium transfer into the digestive tract and consequently the transfer of radiocesium into the wild boar muscles is of great importance as the knowledge of this process might contribute to the development of countermeasures against possible muscle contamination. Therefore, the aim of this study was to explain the source of 137Cs in wild boar food in the natural ecosystem with the main emphasis on analyses of muscles and the content of stomach, and to find possible dependence of 137Cs activity in muscles on the sex of animals. Materials and Methods Wild boars weighing 20 to 100 kg originated from two adjacent locations (Sabrava and Dvorce) situated in the Odry Highlands and partly in the Nizký Jesenik mountains. The landscape is a typical upland (600 m above sea level on the average) with rich spruce forests, at lower altitudes with mixed forests and isolated beech and birch forests, and willows and alders near watercourses. There are large meadowlands and grasslands situated among individual forests. Arable land is quite rare; small-scale watercourses that formed deep valleys by erosion activity have strongly affected the landscape. Twenty two muscle samples and eleven samples of the stomach content were taken from wild boars of the weight ranging from 20 to 100 kg from 8 November 2006 to 4 April 2008 to determine the 137Cs specific activities. Twenty surface land samples were collected from the places rooted by animals and up to a distance of 2 m from them. All typical food items were collected, i.e. soil, needles, earthworms, beechnuts, rootlets, and mushroom Elaphomyces granulatus). Some additional foods (maize silage, sugar slices and oat) were also included. Stomach content sample with the specific activity of 100 Bq·kg-1 was rinsed by water and sorted according to the grain size on the 1 mm screen. The samples were not dried; all were measured in their native state or cooled to a temperature of –15 oC, and then measured. The 137Cs specific activities were measured using gamma-spectrometry with the semiconductor HPGe GC2020 detector (efficiency of 20%, resolution at 1.3 MeV of 1.8 keV) and the Inspector multichannel analyser. Three measurement geometries (i.e. methods of measurements) were used in this study: muscles were measured in the Marinelli beaker (450 ml), the contents of stomach and other potential radiocesium sources in 200 ml PE bottles (200 ml) and separated parts of stomach in Petri dishes (10 ml). All geometries including the gammaspectrometric system were certified in the Czech Metrological Institute. The following minimum detectable activities (MDA) for the measuring time of 3 h were determined: 0.9 Bq·kg-1 in the Marinelli beaker, 5.2 Bq·kg-1 in PE bottles and 83 Bq·kg-1 in Petri dishes. However, the measuring time was extended for some samples to 18 h with the following MDA: 0.4 Bq·kg-1 in the Marinelli beaker, 2.2 Bq·kg-1 in PE bottles and 10 Bq·kg-1 in Petri dishes. The combined relative standard uncertainties were calculated according to the Guide (1993). Details of the system were described by Dvořak et al. (2006). Statistics were evaluated by means of the basic parameters (modus, mean, and median) and by the polynomial curves describing the time trends. The effect of sex on the muscle activity concentrations was assessed by means of paired t-test with non-homogeneous variation.

/pdf/transfer-of-radiocesium-into-wild-boar-meat-ntz39lmiek.pdf

Transfer of Radiocesium into Wild Boar Meat

Eggs from laying hens were irradiated using radioactive Co-60 at a dose of 1 kGy, 2.5 kGy, and 5 kGy, with a dose input of 3.21 kGy h−1. Parameters describing the colour of egg yolk such as L*, a*, and b*, were determined spectrophotometrically using the CIELAB system with the help of the portable spectrophotometer Superchroma S-Spex without gloss. The levels of all three parameters dropped upon ionizing radiation. While at a dose of 1 kGy the difference in the parameters was not statistically conclusive, after irradiation using doses of 2.5 kGy and 5 kGy, the levels of the parameters L*, a*, and b* showed a statistically conclusive decrease which was also accompanied with changes in sensorial properties such as decolouration and decreased colour. The colour of the yolk was evaluated according to the Roche scale, showing that more significant changes occurred upon irradiation at doses of 2.5 and 5 kGy (the value decreased from 6 to 5). The number of acidity estimated in egg yolk (mg KOH/g of fat) increased with the increasing dose, being conclusively higher only for doses of 2.5 kGy and 5 kGy.

Changes in the colour and the acidity number of egg yolk upon irradiation

Dvofiak P., E. Strakova, J. Kunova, V. Kunova: Egg Yolk Colour Dependis upon the Composition of the Feeding Mixture for Laying Hens. Acta Vet Brno 2007, 76: 121-127. The aim of this study was to verify the possibility of replacement of fish meal by specially treated meal made of yellow lupin seed in relation to the yolk colour. The experiment was performed with 72 laying hens divided into two groups. The experimental group including 36 laying hens received a feeding mixture containing meal made of yellow lupin seed (the JUNO variety) which replaced fish meal used as an animal protein component in feeding mixtures in the control group. Samples of eggs were collected monthly in the course of seven months to determine the colour of egg yolk. Yolk colour was determined by the spectrophotometric method using the CIELAB system. Measurement with the exclusion of gloss was carried out using a portable spectrophotometer. The average values of parameter L* decreased significantly (α = 0.05), which confirmed the darkening of eggs. Parameters a* showed a significant increase (ANOVA α = 0.01), whereas the differences in the individual months ranged from 1.1 to 3.9. Yolk had distinct red-orange colour. Parameters b* did not show significant differences, however, the yolk tended to have an intensive yellow colour. The presence of yellow lupin seed meal in the feeding mixture resulted in a more distinct yellowred colour of egg yolk. CIELAB, lupin seeds, pigments, food colour, spectrophotometer, fish meal

/pdf/egg-yolk-colour-depending-upon-the-composition-of-the-4x1bw306oy.pdf

Egg Yolk Colour Depending upon the Composition of the Feeding Mixture for Laying Hens

BACKGROUND: This study attempts to compare two possibilities of enhancing the colour of egg yolk. One of them is based on the ecological rearing of laying hens on natural green grass whereas the other uses a feeding dose supplemented with natural pigments in laying hens reared in individual cages. Is it possible to distinguish these two technologies using yolk colour determination in the CIELAB system?

RESULTS: Yolk colour parameters such as L*, a*, and b* in the group of grazed hens are significantly different (α = 0.001) from those observed in hens reared in cages. The yolk colour shows a darker, redder and more yellow colour. The greatest difference was seen in the red colour parameter, a*, that increased more than twice. Visually, this means a shift towards a more orange colour. Compared to grazing in the meadow (ΔE* = 13.257), the addition of artificial pigments in the feed resulted in a more significant increase in the parameter ΔE* (CIE total colour difference), with the greatest value of ΔE* being observed with the use of both pigments (ΔE* = 24.265).

CONCLUSION: Grazing increases the parameter a* whereas the values of the parameter C*ab remain relatively low. The parameter ΔE* is significantly lower in the case of grazing as compared to the supplementation of the feed with pigments. However, colourity parameters cannot be used as a specific standard to identify a particular grazing technology as their values vary during the laying period. Copyright © 2011 Society of Chemical Industry

Petr Dvořák

Papers

Employing Ionizing Radiation to Enhance Food Safety - a Review

Transfer of Radiocesium into Wild Boar Meat

Changes in the colour and the acidity number of egg yolk upon irradiation

Egg Yolk Colour Depending upon the Composition of the Feeding Mixture for Laying Hens

Possibilities of enhancing the colour of egg yolk.