Production of T-2 toxin and deoxynivalenol in the presence of different disinfectants

The aim of the work was to examine the effect of different disinfectants on production trichothecenes (especially of T-2 toxin and deoxynivalenol). Lipophilicity, chemical structure, the presence of bioactive groups and functional groups in their structure modifies biological activity and toxic potency of trichothecenes. For this reason, limits have been established designating maximum levels of mycotoxins in cereals while maintaining proper growing practices. Appropriate nutritive media were prepared with different concentration of tested disinfectants (Desanal A  plus, ProCura spray and Guaa-Pool) and were inoculated using  Fusarium strains. The density of  Fusarium was 105 spores per mililitre. Nutrient media was cultivated at 15 °C and 25 °C for seven days. The strains of Fusarium graminearum CCM F-683 and Fusarium species (isolated from barley) produced quantities of deoxynivalenol. Fusarium poae CCM F-584 and Fusarium species (isolated from malthouse air) produced quantities of T-2 toxin. Desanal A plus prevented Fusarium growth and production of T-2 toxin and deoxynivalenol at the concentration 10%. It is an alkaline disinfectant on the basis of active chlorine and the surfactant that contains ˂5% of NaClO. ProCura spray at the concentration 0.6% proved to be very effective. This disinfectant contains 35% of propan-1-ol and 25% of propan-2-ol.  Guaa-Pool at the concentration 0.004% proved to be very effective. It is a polymeric disinfectant with anion surface-acting agent and it contains ˂0.9% of polyhexamethylene guanidine hydrochloride and ˂0.2% of alkyl (C12-C16) dimethylbenzyl ammonium chloride. Lower contentration of  disinfectants that  not prevented growth of Fusarium caused higher production  of T-2 toxin and deoxynivalenol. The contents of T-2 toxin and deoxynivalenol were analyzed by enzyme-linked immunosorbent assay (ELISA) using commercially produced kits (Agra Quant® Deoxynivalenol Test kit and Agra Quant® T-2 toxin Test kit). The experiment showed that the variability in the production of T-2 toxin and deoxynivalenol depended on the Fusarium strain used, concentration of disinfectants and temperature of cultivation

The effect of processing temperature on microbial safety and antioxidant activity of minimally processed "raw food"

The assessment of the effect of dehydration temperatures (40 °C, 50 °C, and 60 °C) on the microbiological quality, antioxidant activity and oxidative stability of lipids of buckwheat-based minimally processed "raw food" (MPRF) was performed. Buckwheat flakes with various ingredients were soaked in sterile distilled water for 20 h, then MPRF samples were formed and dehydrated at constant temperature. Total viable counts, coliform, fungi, yeasts and aerobic spore-forming bacteria counts were evaluated in dehydrated products. While fungi were effectively reduced at all drying temperatures, higher total viable and coliform counts were found in MPRF samples after drying at 40 °C and 50 °C. Generally, antioxidant activity of MPRF samples did not significantly differ, and superoxide dismutase activity remained constant with the increase of drying temperature. The inhibition of lipid peroxidation was significantly higher in MPRF samples dehydrated at 40 °C than in those dehydrated at higher temperatures. Lipid oxidation stability measured by peroxide value, conjugated dienes content and thiobarbituric acid-reactive substances assay was not substantially affected during the dehydration process. Preparing MPRF by dehydration at 40 °C and 50 °C was considered as representing a microbial hazard whereas overall antioxidant activity was found to be minimally influenced by the dehydration temperatures. © 2016 National Agricultural and Food Centre (Slovakia).University of Pardubice, Pardubice, Czech Republic [SGS_2016_001

Influence of chosen microbes and some chemical substances on the production of aflatoxins

Aflatoxins are produced as secondary metabolites by A. flavus, A. parasiticus, A. nomius and A. tamarii. The aflatoxin biosynthetic pathway involves several enzymatic steps and genes (apa-2, ver-1) that appear to be regulated by the aflR gene in these fungi. The aim of this work was the detection of aflatoxins by the HPLC method and the ascertainment of factors influencing their production. A. parasiticus CCM F-108, A. parasiticus CCF 141, A. parasiticus CCF 3137 and two isolates A. flavus were used. These toxigenic isolates were recovered from spice (strain 1) and wraps (strain 2). The gene for the production of aflatoxin B1 for each species of fungi was detected using an optimized PCR method. Rhodotorula spp.*, Lactococcus lactis subsp. lactis CCM 1881, Flavobacterium spp. and fungal strain Pythium oligandrum* were tested for inhibition of aflatoxins production and fungal growth. Having used the HPLC detection, various preservatives (propionic acid, citric acid, potassium sorbate) were tested from the viewpoint of their influence on the growth of aflatoxigenic fungi followed by the production of aflatoxins. The growth of A. flavus and A. parasiticus and aflatoxin production in Potato Dextrose Agar supplemented with propionic acid (1000-2000-3000 mg/kg), citric acid (2000-3000-4000 mg/kg) and potassium sorbate (500-800-1000 mg/kg) was tested by Agar Dilution Method. After 72 h of incubation was evaluated growth of fungi, all samples were frozen for later extraction and aflatoxins quantification by HPLC. Effect of peptone and sucrose additions were studied in yeast extract (2%) supplemented with peptone (5-10-15%) or sucrose (15%). Growth inhibition of Aspergillus by Pythium oligandrum was tested on wood surface. As shown, the highest inhibition effect on the aflatoxins production was obtained when propionic acid was applied in concentrations since 1000 mg/kg. A total inhibition of the fungi growth and aflatoxins production was observed in all samples containing peptone in the concentration range tested. Significant limitation of the growth and production of aflatoxins was also observed in the presence of other microorganisms such like Pythium oligandrum and Rhodotorula spp

Detection of toxigenic fungi and aflatoxins production in food and feed

Práce se zabývá detekcí toxinogenních půísní pomocí molekulárně biologických metod, produkcí aflatoxinů v potravinách a krmivech a jejich stanovení metodou HPLC.Katedra analytické chemi

The impact of health on the participation of people of pre-retirement age in the labor market in the Czech Republic in the years 2011 to 2021

Tato bakalářská práce analyzuje vliv zdraví na účast osob v předdůchodovém věku na trhu práce v ČR v letech 2011 až 2021. Cílem práce je zhodnotit, jakou roli hraje zdravotní stav osob ve věku 55-64 let na jejich zapojení na pracovním trhu a navrhnout hospodářsko-politická doporučení. Stárnutí populace a nízká porodnost představují jedny z největších problémů vyspělých zemí. Vyšší zapojení osob v předdůchodovém věku na trhu práce může snížit negativní sociální a finanční dopady. Teoretická část práce je věnována ekonomickým aspektům trhu práce, faktorům, které ovlivňují nabídkovou a poptávkovou stranu pracovního trhu a vlivu zdraví. Praktická část zkoumá vliv zdraví na účast osob ve věku 55-64 let na trhu práce na základě získaných statistických dat a provedené komparativní analýzy, která vyhodnocuje stanovené hypotézy. Výsledky analýzy nepotvrzují přímou závislost mezi stavem zdraví a účastí osob ve věku 55-64 let na trhu práce.The bachelor’s thesis analyses the impact of health on the participation of people of pre-retirement age in the labor market in the Czech Republic in the years 2011 to 2021. The goal of this work is to evaluate the role of health conditions of people in age between 55-64 on their involment in labor market and to suggest economic policy recommendations. Population aging and low birth rates are one of the biggest problems in developed countries. Higher participation of people of pre-retirement age in the labor market can reduce the negative social and financial impacts. The theoretical part of the work is devoted to economic aspects of the labor market, factors that affect the supply and demand side of the labor market and the impact of health. The practical part examines the impact of health on the participation of people aged 55-64 in the labor market based on statistical data and a comparative analysis, which evaluates the established hypotheses. The results of the analysis do not confirm a direct relationship between the state of health and the participation of people aged 55-64 in the labor market

The quality of fruit bars and crackers designated for the raw food vegan diet

Fruit bars and crackers designated for the raw vegan diet were evaluated with regard to the microbial quality, the presence of antioxidants (phenolics, flavonoids, and condensed tannins), and antioxidant properties. Since these products had been subjected to air drying up at 42 °C, the oxidation state of the fat (peroxide and thiobarbituric values) and the activity of superoxide dismutase and catalase was determined. In general, the samples were considered to be of good microbial quality, high antioxidant content, and capacity. As found out, the drying process did not alter the lipid oxidation and kept the activity of catalase constant in finished products

Kvalita ovocných tyčinek a krekrů určených pro výživu veganů

Fruit bars and crackers designated for raw vegan diet were evaluated with regard to the microbial quality, the presence of antioxidants (phenolics, flavonoids and condensed tannins), and antioxidant properties. Since these products were subjected to air drying up to 42 °C, the oxidation state of the fat (peroxide and thiobarbituric values) and the activity of superoxide dismutase and catalase was determined. In general, the samples were considered to be in good microbial quality, high antioxidant content and capacity. The drying process did not alter the lipid oxidation and kept the activity of catalase in finished products.Ovocné tyčinky a krekry určené pro výživu veganů byly hodnoceny s ohledem na mikrobiální kvalitu, obsah fenolických látek, flavonoidů a kondenzovaných taninů a jejich antioxidační aktivitu. Vzhledem k použité tehchnologii výroby (sušení při 42 °C) byla také zjišťována oxidační stabilita lipidů (peroxidové a thiobarbiturové číslo) a aktivita superoxid dismustásy a katalázy. Obecně řečeno, výrobky vykazovaly dobrou mikrobiologickou kvalitu a vysoký obsah látek s antioxidačním účinkem. Technologie výroby neovlivnila zásadním způsobem kvalitu lipidů a aktivitu katalázy

Vitariánská strava: vliv teploty sušení na antioxidační vlastnosti a mikrobiální kontaminaci

A raw food vegan (RFV) diet is one that consists of only uncooked plant-derived products. Since the fresh food products can deteriorate during storage, the moderate temperature treatment is allowed up to 46°C according to the popular literature. RFV adherents believ that plant-derived food prepared in such a way keep the nutrients almost untouched. The effect of moderate drying temperature (40°C–80°C) on the antioxidant properties of various fruits and vegetables was assessed using meta-analytical approach. While ascorbic acid content has decreased with the increase in drying temperature, total phenolic and flavonoid content did not reduce with the increase of drying temperature. In order to elucidate the effect of moderaty drying temperature on the quality of RVF diet, buckwheat-based cookies we prepared according to the popular recipe including soaking of ingredients in tap water, formation of cookies followed by their drying at various temperatures. Antioxidant properties measured in terms of DPPH and ABTS radical scavenging activity were significantly reduced when compared with raw matter (after soaking). However, drying at 40°C, 50°C or 60°C for 20 h gave similar values for all the parameters indicating that increasing drying temperature did not affect antioxidant properties. In addition, the same trends were obtained for inhibition of lipid peroxidation and superoxid dismutase activity in buckwheat-based samples. Drying buckwheats or other ingredients at 40°C may exhibit serious microbial hazard. In our experiments, significant reduction of coliforms has occured after drying at 50°C and total bacterial count decreased after drying at 60°C. Aerobic-spore forming bacteria count remained constant at each temperature level. Soaking process was identified as the critical point regarding the proliferation of coliform bacteria, particuarly when soaked at ambient temperature. Drying at 40°C resulted in sharp increase in Escherichia coli count. Although buckwheat-based products dried at 40°C have retained high antioxidant properties than those dried at higher temperatures, serious health implication may occure due to the high content of bacteria, particluarly E. coli.Práce popisuje vlivy různých teplot sušení (40°C–70°C) na mikrobiální kvalitu výrobků z pohanky seté současně se stanovením vybraných parametrů antioxidační kapaicty, stability tuků a obsahu vybraných flavonoidních látek. Nejvyšší riziko při přípravě bylo zjištěno v procesu namáčení ingrediencí po dobu 20 h bez ohledu na teplotu prostředí (5°C vs. 20°C). Po namáčení došlo k výraznému nárůstu sledovaných skupin mikroorganismů. Sušení při 40 °C mělo za následek další zvýšení počtu, během sušení při teplotách 50°C–70°C došlo postupně k jejich redukci. Antioxidační kapacita, stejně jako obsah fenolických látek, flavonoidů a kondenzovaných taninů byla nejvyšší u nesušených výrobků. Sušením došlo ke snížení obsahu, nicméně již nezáleželo na teplotě sušení

How baking temperature affects the quality of raw food vegan diet?

V práci byly stanoveny mikrobiologická kvalita, obsah antioxidačních látek, antioxidační kapacita, kvalita tuků a aktivita enzymu katalázy u vzorků ovocná tyčinka a mrkvové krekry určených pro vitariány před a po vystavení teplotě 220 °C (5 min). Výsledky ukazují na dobrou kvalitu jak po stránce mikrobiologické, tak v parametrech určujících kvalitu tuků. Výrobky se vyznačují vysokou antioxidační kapacitou související s poměrně vysokým obsahem fenolových látek, flavonoidů a kondenzovaných taninů. U obou vzorků byla také zaznamenána aktivita enzymu katalázy. Po vystavení teplotě pečení bylo zaznamenáno snížení počtu některých skupin mikroorganismů (kvasinky, plísně, koliformní bakterie), dále zvýšení obsahu antioxidačních látek a antioxidační kapacity. Kvalita tuků byla i po zahřátí vzorků vyhovující, enzymová aktivita nebyla zaznamenána.Microbiological loads, antioxidant content, antioxidant capacity, fat quality, and activity of catalase of fruit bar and carrot cracker samples for raw food vegans were determinated before and after baking temperature treatment at 220 °C for 5 min. Good quality of samples was described by the low microbiological counts, and by the low values describing the fat quality. High antioxidant capacity was determinated correlating with higher content of phenolics, flavonoids, and condensed tannins. The catalase activity was also detected. After the high temperature treatment, the decrease of yeasts, fungi and coliform bacterial counts was observed together with the increase of antioxidant content and capacity. While the quality of fat did not alter with temperature treatment, the enzyme activity has diminished

Kvalita ovocných tyčinek a krekrů určených pro výživu veganů

Fruit bars and crackers designated for raw vegan diet were evaluated with regard to the microbial quality, the presence of antioxidants (phenolics, flavonoids and condensed tannins), and antioxidant properties. Since these products were subjected to air drying up to 42 °C, the oxidation state of the fat (peroxide and thiobarbituric values) and the activity of superoxide dismutase and catalase was determined. In general, the samples were considered to be in good microbial quality, high antioxidant content and capacity. The drying process did not alter the lipid oxidation and kept the activity of catalase in finished products.Ovocné tyčinky a krekry určené pro výživu veganů byly hodnoceny s ohledem na mikrobiální kvalitu, obsah fenolických látek, flavonoidů a kondenzovaných taninů a jejich antioxidační aktivitu. Vzhledem k použité tehchnologii výroby (sušení při 42 °C) byla také zjišťována oxidační stabilita lipidů (peroxidové a thiobarbiturové číslo) a aktivita superoxid dismustásy a katalázy. Obecně řečeno, výrobky vykazovaly dobrou mikrobiologickou kvalitu a vysoký obsah látek s antioxidačním účinkem. Technologie výroby neovlivnila zásadním způsobem kvalitu lipidů a aktivitu katalázy