360 research outputs found

    Management of food cold chains traceability amid the COVID-19 pandemic

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    The present article considers the functioning of food supply chains and their major component — a continuous cold chain of perishable food products, including meat products, under the conditions of COVID‑19 pandemic. The issues of the impact of the pandemic on production, processing and commercial supply of meat and meat products in Russia and worldwide are being considered. The traceability of temperature fluctuations in meat processing plants is relevant; it becomes an increasingly important factor for efficient logistics to provide the best supply and to keep the food safe in the current conditions. Research data is presented here. The results of the research show that frozen foods serve as carriers and distributors of SARS-CoV‑2 infection without any contact between people. This conclusion highlights additional challenges in controlling the spread of COVID‑19 worldwide, and reveals the mechanism of the disease transmission, taking into account the peculiarities of temperature modes during storage and transportation of perishable meat products. The risks of food cold chains functioning under the conditions of pandemic, the adaptive strategies for their mitigation and logistical systems of tracking are considered, in particular, the application of various data technologies

    Study of the process of the frozen raw beef defrosting with its simultaneous massaging in industrial conditions

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    Many meat processing enterprises use the frozen raw meat. Its defrosting and thawing is a crucial technological operation that fundamentally affects the quality of food products. The experience and knowledge obtained directly in the workshop in the process of thawing the raw materials and their using to obtain a specific finished product are of great importance. Defrosting and thawing of the frozen beef meat, as one of the stages of raw meat processing, still remains a challenging process in industrial food production. The importance of this process is constantly increasing due to the growing volumes of frozen raw materials processed in food enterprises. Scientific research shows that one of the most efficient methods of defrosting and thawing is the process of meat thawing with saturated water steam under vacuum. When applying the steam the raw materials is heated at its least and minimal losses are observed, while the duration of the process is significantly reduced. This work examines the process of beef meat defrosting and thawing with simultaneous shaking and crumpling the frozen mass, which can be called as massaging of raw materials. As studies have shown, this method of thawing makes it possible to reduce losses down to almost zero and obtain raw materials with good structural characteristics for the production of a finished product with a wide range of consumer properties. The obtained experimental curves of changes in the mass and temperature of raw materials make it possible to analyze the kinetics of heat transfer and mass transfer processes at the macro- and micro levels of the food system, which serve as the basis for modeling and controlling the technological process. This study presents the results of conventional defrosting and thawing of the raw meat but combined with massaging. Studies of the parameters of processing modes have shown that the proposed program makes it possible to use efficiently the design and technological features of the defroster-massager in order to obtain the raw beef for the production of high-quality food products. The results of experimental studies and their analysis allow making conclusion about the prospects of applying this process for the other types of raw meat materials before the main technological processing of raw materials

    AN EFFECT OF STORAGE AND TRANSPORTATION TEMPERATURE ON QUANTITATIVE AND QUALITATIVE COMPOSITION OF MICROFLORA OF PLANT PRODUCTS

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    The results of the study on changes in the composition and quantity of epiphytic and endophytic microorganisms of plant products during storage and transportation are presented. For the investigation, the authors took apple fruits and leafy spicy green products that had biological peculiarities and allowed investigating processes of the long-term and short-term main stages (cold storage, transportation by refrigerated transport, presales storage) of the continuous cold chain on the way to a consumer. Apple fruits were placed in storage in cold chambers with the temperature regimes of plus (2–3)°C and minus (1–2)°C, where they were stored for 90 days. The vegetative organs of dill and parsley were transported during 8 hours by a refrigerated truck and placed in the commercial refrigeration equipment at two temperature regimes (4–5) C and (0–1) C for 72 hours for presales storage. The results of the microbiological analysis showed that the number of endophytic microorganisms (bacteria, yeasts and molds) was lower by 1–3 orders of magnitude in apple fruits and by 2–3 times in green vegetables compared to the number of epiphytic microorganisms. It was established that the regime of storage at negative temperatures completely inhibited the development of epiphytic bacteria on fruits, significantly delayed the multiplication of epiphytic yeasts and molds; while at a positive temperature the number of bacteria increased approximately by 10–17 times, yeasts by 180 times and molds by 3 times. The dynamics of changes in the number of endophytic microorganisms during storage showed the same trend that was observed for epiphytic microorganisms. Analysis of the microbial quantity after transportation of green products showed an increase in abundance of the revealed groups of epiphytes and endophytes by 1.5–3 times upon absolute prevalence of bacteria. After short-term storage, a significant growth of the revealed microbial groups was found; with that, their quantity was 1.5–6.5 times higher at (4–5) C than at (0–1) C. The authors experimentally confirmed the conclusion that with respect to reduction of losses due to microbiological spoilage and extension of shelf life, the cold storage regime of the studied plant products at near-zero temperatures is preferable compared to the regimes of storage at higher positive temperatures.The results of the study on changes in the composition and quantity of epiphytic and endophytic microorganisms of plant products during storage and transportation are presented. For the investigation, the authors took apple fruits and leafy spicy green products that had biological peculiarities and allowed investigating processes of the long-term and short-term main stages (cold storage, transportation by refrigerated transport, presales storage) of the continuous cold chain on the way to a consumer. Apple fruits were placed in storage in cold chambers with the temperature regimes of plus (2–3)°C and minus (1–2)°C, where they were stored for 90 days. The vegetative organs of dill and parsley were transported during 8 hours by a refrigerated truck and placed in the commercial refrigeration equipment at two temperature regimes (4–5) C and (0–1) C for 72 hours for presales storage. The results of the microbiological analysis showed that the number of endophytic microorganisms (bacteria, yeasts and molds) was lower by 1–3 orders of magnitude in apple fruits and by 2–3 times in green vegetables compared to the number of epiphytic microorganisms. It was established that the regime of storage at negative temperatures completely inhibited the development of epiphytic bacteria on fruits, significantly delayed the multiplication of epiphytic yeasts and molds; while at a positive temperature the number of bacteria increased approximately by 10–17 times, yeasts by 180 times and molds by 3 times. The dynamics of changes in the number of endophytic microorganisms during storage showed the same trend that was observed for epiphytic microorganisms. Analysis of the microbial quantity after transportation of green products showed an increase in abundance of the revealed groups of epiphytes and endophytes by 1.5–3 times upon absolute prevalence of bacteria. After short-term storage, a significant growth of the revealed microbial groups was found; with that, their quantity was 1.5–6.5 times higher at (4–5) C than at (0–1) C. The authors experimentally confirmed the conclusion that with respect to reduction of losses due to microbiological spoilage and extension of shelf life, the cold storage regime of the studied plant products at near-zero temperatures is preferable compared to the regimes of storage at higher positive temperatures

    Changes in the Qualitative Composition of the milk of Holstein Cows During Summer Chronic Heat Stress

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    Seasonal summer heat stress leads to significant economic losses, resulting in a drop in milk yield in dairy cows and a deterioration in milk quality. The purpose of this study was to determine the changes in some qualitative parameters of milk in Holstein cows during chronic heat stress on one of the largest commercial dairy farms Ukraine (50°49′14″ N, 31°49′23″ E). Five multiparous cows of medium lactation with a milk yield of about 30 kg per day were randomly selected into the reference (in the spring, at the end of May) and the experimental group (in the summer, at the end of August). Milk samples were taken from cows during the morning milking. Qualitative analysis of milk included the identification of milk solids-not-fat, density, mass fraction of lactose, fat, protein and minerals, as well as the freezing point, electrical conductivity and active acidity using ultrasonic method. Animals were kept in naturally ventilated barns. The total mixed single-type balanced diet consisting of corn silage and concentrates that the cows received remained unchanged. The sampling of milk from cows of the experimental group was preceded by a continuous 26-day hot period, during which the maximum daily values of the temperature and humidity index did not fall below 72 units. The results showed that in the milk of the animals of the experimental group there was a significant decrease in the content of milk solids-not-fat, the mass fraction of fat and protein (P0.05). The mass fraction of lactose and minerals tended to increase. It should be noted that the average daily milk yield of dairy cows in the herd in spring and summer was almost at the same level. In conclusion, the results of the study showed that high summer temperatures lead to a deterioration in the quality of milk in Holstein cows. Despite the decrease in milk density and freezing point, these figures met the requirements of the standard. Organoleptic indicators of milk, electrical conductivity and active acidity of milk did not change in hot weather, their value indicated the naturalness of milk. The mass fraction of milk fat, which undergoes the greatest change under the influence of seasonal heat stress, is one of the most valuable components of milk, which has a direct effect on nutritional value and purchase price of raw milk. Therefore, a further deeper study of the fatty acid composition of milk using the method of chromato-mass spectrometry will provide valuable data necessary to search for possible herd management strategies to maintain high milk quality under conditions of seasonal heat stress

    Maser Oscillation in a Whispering-Gallery-Mode Microwave Resonator

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    We report the first observation of above-threshold maser oscillation in a whispering-gallery(WG)-mode resonator, whose quasi-transverse-magnetic, 17th azimuthal-order WG mode, at a frequency of approx. 12.038 GHz, with a loaded Q of several hundred million, is supported on a cylinder of mono-crystalline sapphire. An electron spin resonance (ESR) associated with Fe3+ ions, that are substitutively included within the sapphire at a concentration of a few parts per billion, coincides in frequency with that of the (considerably narrower) WG mode. By applying a c.w. `pump' to the resonator at a frequency of approx. 31.34 GHz, with no applied d.c. magnetic field, the WG (`signal') mode is energized through a three-level maser scheme. Preliminary measurements demonstrate a frequency stability (Allan deviation) of a few times 1e-14 for sampling intervals up to 100 s.Comment: REVTeX v.4, 3 pages, with a separate .bbl file and 3 .eps figure

    Computer prediction of biological activity spectra of substituted and fused methylxanthines

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    Based on the chemical structure and mathematical algorithm of the Prediction of Activity Spectra for Substances software, computer prediction of possible types of biological activity of 121 substances substituted and fused derivatives of methylxanthine, has been done. The structure of compounds synthesized has been confirmed by modern physical and chemical methods: elemental analysis, UV-, IR-, HNMR- and mass-spectrometry, counter synthesis. The purity of the synthesized compounds has been controlled by thin layer chromatography. These substances are white crystalline powders, odorless, of a bitter taste, insoluble in water, soluble in dimethylformamide and dimethylsulfoxide and practically insoluble in alcohol, ether, chloroform, glacial acetic acid. Chemical structures of tested compounds have been introduced by a computer program “Java 6 Standart Edition” and posted on the official site of biological spectra prediction (http://195.178.207.233/PASSNew/predsct.php) in the form of the original multi-atomic orbital descriptors (Multilevel Neighborhoods of Atoms). The results of the computer prediction of the diuretic activity have been considered positive if the predicted activity probability of the substance Pa has been > 0.5. It has been specified that the newly synthesized derivatives of methylxanthine are able to demonstrate the following pharmacological activities: diuretic, neurotropic, antihypoxic, analgesic, anti-inflammatory and metabolic. By the method of computer prediction for substituted and fused methylxanthine derivatives it has been found that the highest diuretic activity is characteristic of the compound g-6713 - pyrrolidine 1,7-dimethylimidazo[1,2-f]xanthinyl acetate. The substituted and fused derivatives of methylxanthine present a promising group of compounds for further synthesis and screening of new pharmacological substances with diuretic properties

    Structural features of Ni-Cr-Si-B materials obtained by different technologies

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    This study considers the structural features of Ni-Cr-Si-B (Ni - base; 15.1 % Cr; 2 % Si; 2 % B; 0.4 % C) materials obtained by different methods. The self-fluxing coatings were deposited by plasma spraying on the tubes from low carbon steel. Bulk cylinder specimens of 20 mm diameter and 15 mm height were obtained by spark plasma sintering (SPS). The structure and phase composition of these materials were investigated by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The major phases of coatings and sintered materials are [gamma]-Ni, Ni[3]B, CrB and Cr[7]C[3]. We demonstrate that the particle unmelted in the process of plasma spraying or SPS consist of [gamma]-Ni-NEB eutectic and also CrB and Cr[7]C[3] inclusions. The prolonged exposure of powder to high temperatures as well as slow cooling rates by SPS provide for the growth of the structural components as compared to those of plasma coatings materials. High cooling rates at the plasma spraying by melted particles contribute to the formation of supersaturated solid solution of Cr, Si and Fe in [gamma]-Ni. The structure of the melted particles in sintering material has gradient composition: the core constituted of Ni grains of 10 μm with [gamma]-Ni-Ni[3]B eutectic on the edges. The results of the experiment demonstrate that the sintering material has a smaller microhardness in comparison with plasma coatings (650 and 850 MPa, respectively), but at the same time the material has higher density (porosity less than 1 %) than plasma coatings (porosity about 2.. .3 %)

    Metal-free transannulation reaction of indoles with nitrostyrenes: a simple practical synthesis of 3-substituted 2-quinolones

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    3-Substituted 2-quinolones are obtained via a novel, metal-free transannulation reaction of 2-substituted indoles with 2-nitroalkenes in polyphosphoric acid. The reaction can be used in conjunction with the Fisher indole synthesis offering a practical three-component heteroannulation methodology to produce 2-quinolones from arylhydrazines, 2-nitroalkenes and acetophenone

    Prevalence of cardiac arrhythmias among patients undergoing chronic hemodialysis

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    Aim. To evaluate the prevalence of arrhythmias in patients undergoing chronic hemodialysis, to characterize the arrhythmia types in relation to the dialysis procedure and to determine their relationship with clinical findings and echocardiographic characteristics.Material and methods. The study involved 152 patients with kidney failure undergoing chronic hemodialysis. All patients underwent an assessment of dialysis parameters, collection of clinical data, and 48-hour Holter monitoring. In addition, 93 patients underwent an echocardiography with an assessment of left ventricular (LV) mass index, LV ejection fraction, left atrial (LA) volume index, E/e’, cardiac output and preload, which was defined as increased LV filling pressure (E/e’ >12) and LA enlargement (LA volume index >30 ml/m2).Results. Among the 152 examined patients, premature supraventricular and ventricular contractions (PVCs) were observed in almost all patients, while 41% had paroxysmal supraventricular tachycardia. Clinically significant arrhythmias included persistent atrial fibrillation (AF) in 8,6% of patients, paroxysmal AF in 3,9%, nonsustained ventricular tachycardia in 19,7%, bradycardia in 4,6%, second-degree atrioventricular block in 1,3% and third-degree atrioventricular block among 2,6%. PVCs were more common on dialysis days, while tachyarrhythmias were more common during dialysis and in the immediate post- dialysis period. Older age (odds ratio (OR) 10 years older, 1,53; 95% confidence interval (CI): 1,15-2,03; P=0,003), lower cardiac output (OR 1 L/min more, 0,66; 95% CI: 0,44-1,00; P=0,05) were independently associated with clinically relevant arrhythmias.Conclusion. In patients on chronic hemodialysis, older age, increased preload and lower cardiac output are independently associated with clinically relevant arrhythmias. In addition, a positive association between increased LV mass index and AF episodes has been demonstrated. Lower cardiac output had positive correlation with AF and ventricular arrhythmias
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