EVALUATING THE POTENTIAL OF OZONE MICROBUBBLES FOR INACTIVATION OF TULANE VIRUS, A HUMAN NOROVIRUS SURROGATE

Microbubbles are small gas-filled bubbles with diameters ranging from 50 to 1 μm, and less than 200 nm are called nanobubbles. Their small sizes and large specific surface area result in a high gas dissolution rate and long lifetime in liquid. Ozone is a strong oxidant that destroys microorganisms and only produces oxygen as the final by-product in fresh water. However, due to the poor stability of aqueous ozone, critical gas waste happens during treatments which leads to a high economic loss. Microbubbles have shown promising enhancement of ozone treatment. In previous studies, ozone microbubbles exhibited excellent efficacy in the removal of organic contaminants and inactivation of microorganisms including bacteria, spores, and fungi, but few articles discuss the virus inactivation of ozone microbubbles treatment. Human noroviruses (NoVs) are the primary cause of foodborne illnesses in the US, and the development of effective inactivation methods is crucial. Because of the absence of suitable in vitro cultivation methods for NoVs and the constraints of the available infectivity models for these viruses, most of the studies about inactivation use surrogate viruses that are similar to NoVs in genetics and structure. Tulane virus is a NoV surrogate that can identify the same putative co-factor. This study focuses on the influence of treatment time, disinfectant air exposure, and the presence of organic contaminants on the inactivation efficacy of ozone microbubbles or millimeter bubbles. The results demonstrate that more than one log10 reduction was produced when the Tulane virus was exposed to ozone millimeter bubbles and ozone microbubbles for a short period of time, even in the presence of high organic load (FBS), and the protective effect of the organic load was shown when the disinfectant induced volume increased. The findings indicate that conducting further research on ozone microbubbles in aqueous applications in food-related applications is useful

Growth and ochratoxin a production by aspergillus species in coffee beans: impact of climate change and control using o3[Triatomic oxygen (ozone)]

Coffee is an important beverage product in many parts of the world. During the production and processing of coffee the prevailing environmental factors and rate of drying can have a profound influence on colonisation by mycotoxigenic fungi and contamination with ochratoxin A (OTA). In Kuwait, coffee beans are imported from various parts of the world. The objectives of this project were to (a) to examine the diversity of mycotoxigenic fungi found in green and roasted coffee beans bought in the Kuwaiti market from different source countries and identify the dominant fungal populations, (b) to examine the ecology and ochratoxin A production by the ochratoxigenic strains and species isolated, (c) determine the effect of caffeine concentrations in vitro on growth and OTA production by strains from the Aspergillus section Circumdati and Section Niger groups, (d) evaluate the impact of interacting climate change factors (water activity (aw) x temperature x elevated CO2) on growth and OTA production in vitro and in situ, (e) determine the effect of aw and temperature interactions on ecology of strains of two new species, A. aculeatinus and A. sclerotiicarbonarius, isolated from coffee beans and (f) evaluate the efficacy of gaseous ozone (O3) for controlling OTA producing fungi and control of contamination in coffee beans after treatment and after storage. Cont/d

Biodiversity of mycotoxigenic aspergillus species in Egyptian peanuts and strategies for minimizing aflatoxin contamination

Peanuts are an important crop grown in Egypt for either local consumption or export to European markets. The present study examined the importance of mycotoxigenic Aspergilli in Egyptian peanuts from five different regions (Alexandria, El-Beheira, El- Daqahliya, El-Sharqiya, Asyut) in two seasons (2007, 2008). This led to consideration of different potential strategies to control aflatoxigenic A. flavus strains and associated aflatoxin contamination of peanuts. The most common species in peanuts were from Aspergillus section Flavi, Aspergillus section Nigri and Aspergillus section Circumdati. Both qualitative (coconut cream agar) and quantitative analyses (HPLC) were used to analyse the potential mycotoxin production by strains isolated from peanuts. Of a total of 88 Aspergillus section Flavi strains examined, 90% were aflatoxigenic. Cont/d

Report from the 1st MYCOKEY international conference Global Mycotoxin Reduction in the Food and Feed Chain held in Ghent, Belgium, 11-14 September 2017

Aflatoxins are cancer-promoting natural toxins that are produced by the fungus Aspergillus flavus and Aspergillus parasiticus. Aflatoxins have been regarded as one of the most fatal threat in food safety, due to their strong hepatotoxic, carcinogenic and teratogenic effects on human beings and animals. Among them, aflatoxin B1 (AFB1) is one of the common types which have received considerable attention. Thus, developing a rapid, simple and reliable method for determination of AFB1 in foods is very important. Herein, a preliminary study of Frster resonance energy transfer (FRET) immunoassay based on the cadmium-free quantum dots for determination of AFB1 was described. To avoid the use of hazardous heavy metals, core/shell InP/ZnS quantum dots (QDs) as an alternative for Cd-based QDs were synthesized. A silica shell with epoxy groups was used for water solubilization of the obtained nanoparticles. Then a specific anti-AFB1 monoclonal antibody (mAb) was labelled with the hydrophilic QDs via these highly reactive epoxy groups. Gel electrophoresis was used to control the binding. After that, the FRET system was developed using the Cd-free QDs conjugate as donor. Graphene oxide was selected as acceptor. In order to keep the distance between donor and acceptor close enough, the size of silica coated QDs should be controlled strictly. We found that 1-dodecantiol which was used for ligands change on the surface of InP/ZnS QDs was better than oleylamine and the optimum amount of tetraoxysilane was 5 mu L in the silylanization. Besides, only ethanol and hexane were used to wash silica coated QDs which could ensure good dispersion of QDs in water. The cut-off value for the determination of AFB1 in tube was 10 ng/mL with a preliminary study. Compared to reported FRET assays with Cd-based QDs, the developed FRET was easy-to-operate, visual and safe

The development of a putative microbial product for use in crop production

The challenges faced by the agricultural sector especially around improving production yields using environmentally friendly solutions have received market attention. Biological intervention can range from application of biological products to enhance the nutritional value of crops or to control plant pathogens. Biostart, a biological product that demonstrated growth enhancement when applied in lettuce crops is currently in the market. The product is comprised of a consortium of bacterial isolates (Bacillus licheniformis, Brevibacillus laterosporus and Bacillus laterosporus) but the contribution of the individual isolates to growth enhancement had not been elucidated. Green house experiments on lettuce seedlings with individual and mixed treatments were commissioned to determine such contribution. There was either no or marginal growth enhancement observed in the experiments. The results showed that the product was effective as a consortium and not as individual isolates. Further isolation and screening for potential Bacilli with antifungal properties was undertaken. An isolate identified as Bacillus subtilis that demonstrated inhibition against a wide spectrum of fungi, and especially the phytopathogenic Verticillium dahliae and Fusarium oxysporum, was successfully identified. The isolate was cryo-preserved and cultivated to significant levels at bench scale. A characterized comparison of different putative products with known systematic fungicide showed potential application even of heat treated products. The product showed control V. dahliae when tested in green houses with potatoes and tomatoes as test crops. This isolate has been targeted for further development as a biological control product

Estudio de la reducción química y biológica de hongos y micotoxinas en pan

El deterioro de los alimentos causado por los hongos que producen micotoxinas representa un problema importante en seguridad alimentaria. Los cereales en grano y sus productos derivados, como el pan, frecuentemente están contaminados con hongos micotoxigénicos. Es por ello que en la presente Tesis Doctoral se han estudiado la presencia de 17 micotoxinas en 80 muestras de pan de molde y el riesgo de exposición de la población a estos compuestos. Aflatoxinas (AFs), zearalenona (ZEA) y eniatinas (ENs) han sido detectadas respectivamente en el 20%, 65% y 96% de las muestras de pan analizadas. La presencia de dichas micotoxinas y, sobre todo, de las muestras en las que las AFs y la ZEA superan el límite máximo legislado, planteó la necesidad de buscar metodologías que permitieran reducir estos compuestos. En concreto, se han estudiado dos alternativas naturales a los conservantes convencionales: los isotiocianatos (ITCs) en envases activos y las bacterias ácido lácticas (BALs) como cultivos starters. Los ITCs se originan de la hidrólisis de los glucosinolatos (GLSs), que se encuentran en mostaza, brócoli, coliflor, repollo, etc. Se han evaluado diferentes envases con ITCs y harina de mostaza por sus capacidad para extender la vida útil y reducir la presencia de micotoxinas en los cereales contaminados con Aspergillus parasiticus o Penicillium expansum. Además, se ha determinado el potencial del AITC para reaccionar con ZEA y α-zearalenol (α-ZOL); se han identificado los productos de reacción y se han estudiado la bioaccesibilidad y la biodisponibilidad de las micotoxinas y de los aductos con el AITC. Las BALs se han añadido durante el proceso de cocción para prolongar la vida útil y reducir la producción de AFs en pan contaminado con A. parasiticus. Finalmente, se ha estudiado la capacidad de diferentes BALs para reducir la bioaccesibilidad de las aflatoxinas B1 (AFB1) y B2 (AFB2), a través de un modelo de digestión dinámica in vitro. De los ITCs, únicamente el AITC ha alargado la vida útil y reducido las AFs en pan contaminado con A. parasiticus y la patulina (PAT) producida por P. expansum. Entre las dos harinas de mostaza estudiadas, la harina de mostaza oriental ha sido más eficaz en la reducción de las AFs mientras la harina amarilla en la reducción de la PAT. El AITC puede reaccionar y reducir α-ZOL y ZEA in vitro a niveles de hasta el 97%, formando aductos ZEA/α-ZOL-AITC. Una reducción de las micotoxinas y de sus productos de reacción se ha observado tras el tratamiento de la digestión. Los productos de reacción de las micotoxinas con AITC fueron más biodisponibles durante el estudio de biodisponibilidad comparado con las micotoxinas aisladas. El uso de BALs en la fermentación del pan ha aumentado la vida útil del pan y ha reducido la formación de las AFs. Por último, algunas de las bacterias estudiadas fueron capaces de reducir la bioaccesibilidad de las AFB1 y AFB2 contenidas en pan contaminado hasta un 99%.Food spoilage caused by molds that produce mycotoxins is of primary concern and represents an important food safety problem. Cereal grains and their processed food products, such as bread, are frequently contaminated with mycotoxigenic fungi. Therefore, in this PhD Thesis, the occurrence of 17 mycotoxins in 80 samples of bread loaf and the risk exposure of the population to these toxic compounds were determined. Aflatoxins (AFs), zearalenone (ZEA) and enniatins (ENs) were detected respectively in 20%, 65% and 96% of bread samples analyzed. The presence of these mycotoxins and, above all, the samples in which AFs and ZEA, exceeded the maximum limits established, raised the interest of reducing these compounds. In particular, two natural alternatives to the conventional preservatives were studied: isothiocyanates (ITCs) in active packaging and lactic acid bacteria (LABs) as starter cultures. ITCs are originated from the hydrolysis of glucosinolates (GLSs), which are found in mustard, broccoli, cauliflower, cabbage, etc. Different packaging with ITCs and mustard flour were evaluated for their ability to extend the shelf life and reduce the presence of mycotoxins in cereals contaminated by Aspergillus parasiticus or Penicillium expansum. Furthermore, the potential of AITC to react with ZEA and α-zearalenol (α-ZOL) was determined; reaction products were characterized and bioaccessibility and bioavailability of the mycotoxins and adducts with AITC were studied. LABs were added during the baking process to extend the shelf life and reduce the production of AFs in bread contaminated with A. parasiticus. Finally, the ability of different LABs to reduce the bioaccessibility of aflatoxins B1 (AFB1) and B2 (AFB2), through a model of in vitro dynamic, digestion was studied. Among the ITCs, only AITC extended the shelf life and reduced AFs in bread contaminated with A. parasiticus and patulin (PAT) produced by P. expansum. Among the two mustard flours studied, the oriental mustard flour was more effective in reducing AFs while the yellow flour in the reduction of PAT. AITC can react directly and reduce α-ZOL and ZEA in vitro at levels up to 97%, forming adducts ZEA/α-ZOL-AITC. A reduction of mycotoxins and their reaction products was observed after simulated digestion. Reaction products of mycotoxins with AITC were more bioavailable compared to the isolated mycotoxins. The use of LABs in bread fermentation increased the shelf life of bread and reduced the formation of AFs. Finally, some of the bacteria studied were able to reduce the bioaccessibility of AFB1 and AFB2 contained in contaminated bread up to 99%

Biodiversity of mycotoxigenic aspergillus species in Egyptian peanuts and strategies for minimizing aflatoxin contamination

Peanuts are an important crop grown in Egypt for either local consumption or export to European markets. The present study examined the importance of mycotoxigenic Aspergilli in Egyptian peanuts from five different regions (Alexandria, El-Beheira, El- Daqahliya, El-Sharqiya, Asyut) in two seasons (2007, 2008). This led to consideration of different potential strategies to control aflatoxigenic A. flavus strains and associated aflatoxin contamination of peanuts. The most common species in peanuts were from Aspergillus section Flavi, Aspergillus section Nigri and Aspergillus section Circumdati. Both qualitative (coconut cream agar) and quantitative analyses (HPLC) were used to analyse the potential mycotoxin production by strains isolated from peanuts. Of a total of 88 Aspergillus section Flavi strains examined, 90% were aflatoxigenic. Cont/d.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Biodiversity of mycotoxigenic aspergillus species in Egyptian peanuts and strategies for minimizing aflatoxin contamination

Peanuts are an important crop grown in Egypt for either local consumption or export to European markets. The present study examined the importance of mycotoxigenic Aspergilli in Egyptian peanuts from five different regions (Alexandria, El-Beheira, El- Daqahliya, El-Sharqiya, Asyut) in two seasons (2007, 2008). This led to consideration of different potential strategies to control aflatoxigenic A. flavus strains and associated aflatoxin contamination of peanuts. The most common species in peanuts were from Aspergillus section Flavi, Aspergillus section Nigri and Aspergillus section Circumdati. Both qualitative (coconut cream agar) and quantitative analyses (HPLC) were used to analyse the potential mycotoxin production by strains isolated from peanuts. Of a total of 88 Aspergillus section Flavi strains examined, 90% were aflatoxigenic. Cont/d.EThOS - Electronic Theses Online ServiceGBUnited Kingdo