Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Towards strategies to adapt to pressures on safety of fresh produce due to climate change
    Kirezieva, K.K. ; Jacxsens, L. ; Boekel, T. van; Luning, P.A. - \ 2015
    Food Research International 68 (2015). - ISSN 0963-9969 - p. 94 - 107.
    waterborne disease outbreaks - escherichia-coli o157-h7 - extreme weather events - food safety - pesticide-residues - aflatoxin contamination - mycotoxin contamination - sustainable development - foodborne illness - united-states
    This article outlines the findings from a Delphi study aimed to generate insights from a systems perspective about responding to climate change in terms of food safety of fresh produce. The study identified pressures to food safety of fresh produce at primary production, related to contamination of water sources and production environment with microorganisms, pesticide residues, mycotoxins and heavy metals due to heavy rainfalls and floods, droughts, increased temperature and change in seasonality, as results of climate change. First response to these pressures is realised by the core control activities implemented at farm, and depends on their current implementation and actual operation. The experts highlighted the need to strengthen activities, such as water control (including water treatment and quality monitoring), irrigation method, pesticide management (and pre-harvest intervals), personal hygiene requirements and (cold) storage control. Validating the effectiveness of control activities for the changed circumstances, guidance and training to the farmers was emphasized. Moreover, response strategies were proposed for farms to cope with the pressures immediately after occurring and to adapt long-term with support at the community level. The participating experts represented countries from the global north with industrialised food systems, and from the global south — with structured and traditional food systems. They assessed the likelihood of most pressures as higher for the countries from the global south, which was explained by existing response strategies in the global north. It was proposed that the adaptive and coping capacities of companies, regions and sectors are determined by the currently available adaptation and coping strategies. The pressures to food safety can differ per company, supply chain, region and sector due to variability of current climate vulnerabilities, control activities, and adaptive capacity. This paper argues that future adaptation actions should take into account the context of countries, sectors and companies, thus, focus on improving adaptive capacity from a systems perspective.
    Soil health indicators and Fusarium wilt suppression in organically managed greenhouse soils
    Bruggen, A.H.C. van; Sharma, K. ; Kaku, E. ; Karfopoulos, S. ; Zelenev, V.V. ; Blok, W.J. - \ 2015
    Applied Soil Ecology 86 (2015). - ISSN 0929-1393 - p. 192 - 201.
    gradient gel-electrophoresis - escherichia-coli o157-h7 - wave-like dynamics - 16s ribosomal-rna - bacterial-populations - microbial-populations - pythium-ultimum - nutrient input - wheat roots - corky root
    Soil health has been associated with internal cycling of nutrients, microbial activity and diversity as well as root disease suppression, which are frequently greater in organically than in conventionally managed soils. Resistance and resilience, measured as amplitude and frequency of oscillations in bacterial communities after a disturbance, were suggested as integral indicators of soil health, but until now there is little proof for this hypothesis. In this study, resistance and resilience of microbial communities and 24 soil chemical and biological parameters were analyzed and correlated to suppression of flax wilt (caused by Fusarium oxysporum f.sp. lini) in three experiments. Soil samples were collected on three different dates from a recently converted organic greenhouse and a similar, neighboring greenhouse under conventional management. The dynamics of copiotrophic and oligotrophic bacteria after a disturbance were monitored, and the resistance and resilience were calculated. The organic soil showed significantly higher water-holding capacity, organic matter content, total C and N contents, C: N ratio of the small particulate organic matter fraction, microbial biomass carbon, oxygen uptake rate, copiotrophic and oligotrophic bacterial communities and suppression of flax wilt incidence. After incorporation of a grass-clover mixture in both soils, the densities of copiotrophic and oligotrophic bacteria oscillated over time. The relative amplitudes of the oscillations (in grass-clover amended over non- amended soil) and the frequencies of the oscillations of both trophic groups were lower for the organic soil, indicating that the resistance and resilience of the microbial community were greater in this soil. These results support the hypothesis that the bacterial response to a disturbance can serve as an integral indicator for soil health, including disease suppressiveness. (C) 2014 Elsevier B.V. All rights reserved.
    Editorial : Special issue on the impacts of climate change on food safety
    Uyttendaele, M. ; Liu, C. ; Hofstra, N. - \ 2015
    Food Research International 68 (2015). - ISSN 0963-9969 - p. 1 - 6.
    escherichia-coli o157-h7 - waste-water reclamation - virus monitoring data - time-series analysis - manure-amended soil - north-west europe - infectious-diseases - ambient-temperature - seasonal-variation - potential impacts
    Food safety management systems performance in African food processing companies: a review of deficiencies and possible improvement strategies
    Kussaga, J.B. ; Jacxsens, L. ; Tiisekwa, B.P.M. ; Luning, P.A. - \ 2014
    Journal of the Science of Food and Agriculture 94 (2014)11. - ISSN 0022-5142 - p. 2154 - 2169.
    traditional dairy-products - escherichia-coli o157-h7 - small-scale fermentation - global commodity chain - south-west nigeria - microbiological quality - developing-countries - pesticide-residues - aflatoxin contamination - natural occurrence
    This study seeks to provide insight into current deficiencies in food safety management systems (FSMS) in African food-processing companies and to identify possible strategies for improvement so as to contribute to African countries’ efforts to provide safe food to both local and international markets. This study found that most African food products had high microbiological and chemical contamination levels exceeding the set (legal) limits. Relative to industrialized countries, the study identified various deficiencies at government, sector/branch, retail and company levels which affect performance of FSMS in Africa. For instance, very few companies (except exporting and large companies) have implemented HACCP and ISO 22000:2005. Various measures were proposed to be taken at government (e.g. construction of risk-based legislative frameworks, strengthening of food safety authorities, recommend use of ISO 22000:2005, and consumers’ food safety training), branch/sector (e.g. sector-specific guidelines and third-party certification), retail (develop stringent certification standards and impose product specifications) and company levels (improving hygiene, strict rawmaterial control, production process efficacy, and enhancing monitoring systems, assurance activities and supportive administrative structures). By working on those four levels, FSMS of African food-processing companies could be better designed and tailored towards their production processes and specific needs to ensure food safety.
    Enterobacteriaceae rsistant to third-generation cephalosporins and quinolones in fresh culinary herbs imported from Southeast Asia
    Veldman, K.T. ; Kant, A. ; Dierikx, C.M. ; Essen-Zandbergen, A. van; Wit, B. ; Mevius, D.J. - \ 2014
    International Journal of Food Microbiology 177 (2014). - ISSN 0168-1605 - p. 72 - 77.
    escherichia-coli o157-h7 - klebsiella-pneumoniae - molecular characterization - extended-spectrum - antimicrobial resistance - high prevalence - salmonella - lactamase - thailand - determinants
    Since multidrug resistant bacteria are frequently reported from Southeast Asia, our study focused on the occurrence of ESBL-producing Enterobacteriaceae in fresh imported herbs from Thailand, Vietnam and Malaysia. Samples were collected from fresh culinary herbs imported from Southeast Asia in which ESBL-suspected isolates were obtained by selective culturing. Analysis included identification by MALDI-TOF mass spectrometry, susceptibility testing, XbaI-PFGE, microarray, PCR and sequencing of specific ESBL genes, PCR based replicon typing (PBRT) of plasmids and Southern blot hybridization. In addition, the quinolone resistance genotype was characterized by screening for plasmid mediated quinolone resistance (PMQR) genes and mutations in the quinolone resistance determining region (QRDR) of gyrA and parC. The study encompassed fifty samples of ten batches of culinary herbs (5 samples per batch) comprising nine different herb variants. The herbs originated from Thailand (Water morning glory, Acacia and Betel leaf), Vietnam (Parsley, Asian pennywort, Houttuynia leaf and Mint) and Malaysia (Holy basil and Parsley). By selective culturing 21 cefotaxime resistant Enterobacteriaceae were retrieved. Array analysis revealed 18 isolates with ESBL genes and one isolate with solely non-ESBL beta-lactamase genes. Mutations in the ampC promoter region were determined in two isolates with PCR and sequencing. The isolates were identified as Klebsiella pneumoniae (n = 9), Escherichia coli (n = 6), Enterobacter cloacae complex (n = 5) and Enterobacter spp. (n = 1). All isolates tested were multidrug resistant. Variants of CTX-M enzymes were predominantly found followed by SHV enzymes. PMQR genes (including aac(6')-1b-cr, qnrB and qnrS) were also frequently detected. In almost all cases ESBL and quinolone resistance genes were located on the same plasmid. Imported fresh culinary herbs from Southeast Asia are a potential source for contamination of food with multidrug resistant bacteria. Because these herbs are consumed without appropriate heating, transfer to human bacteria cannot be excluded.
    The arable ecosystem as battleground for emergence of new human pathogens
    Overbeek, L.S. van; Doorn, J. van; Wichers, J.H. ; Amerongen, A. van; Roermund, H.J.W. van; Willemsen, P.T.J. - \ 2014
    Frontiers in Microbiology 5 (2014). - ISSN 1664-302X - 17 p.
    escherichia-coli o157-h7 - enterica serovar typhimurium - manure-amended soil - horizontal gene-transfer - complete genome sequence - pseudomonas-aeruginosa strains - complete nucleotide-sequence - hemolytic-uremic syndrome - fresh-cut lettuce - salmonella-enteric
    Disease incidences related to Escherichia coli and Salmonella enterica infections by consumption of (fresh) vegetables, sprouts, and occasionally fruits made clear that these pathogens are not only transmitted to humans via the “classical” routes of meat, eggs, and dairy products, but also can be transmitted to humans via plants or products derived from plants. Nowadays, it is of major concern that these human pathogens, especially the ones belonging to the taxonomical family of Enterobacteriaceae, become adapted to environmental habitats without losing their virulence to humans. Adaptation to the plant environment would lead to longer persistence in plants, increasing their chances on transmission to humans via consumption of plant-derived food. One of the mechanisms of adaptation to the plant environment in human pathogens, proposed in this paper, is horizontal transfer of genes from different microbial communities present in the arable ecosystem, like the ones originating from soil, animal digestive track systems (manure), water and plants themselves. Genes that would confer better adaptation to the phytosphere might be genes involved in plant colonization, stress resistance and nutrient acquisition and utilization. Because human pathogenic enterics often were prone to genetic exchanges via phages and conjugative plasmids, it was postulated that these genetic elements may be hold key responsible for horizontal gene transfers between human pathogens and indigenous microbes in agroproduction systems. In analogy to zoonosis, we coin the term phytonosis for a human pathogen that is transmitted via plants and not exclusively via animals.
    Pulsed electric field processing of different fruit juices: impac of pH and temperature on inactivation of spoilage and pathogenic micro-organisms
    Timmermans, R.A.H. ; Nierop Groot, M.N. ; Nederhoff, A.L. ; Boekel, M.A.J.S. van; Matser, A.M. ; Mastwijk, H.C. - \ 2014
    International Journal of Food Microbiology 173 (2014). - ISSN 0168-1605 - p. 105 - 111.
    escherichia-coli o157-h7 - listeria-monocytogenes - orange juice - saccharomyces-cerevisiae - apple juice - lactobacillus-plantarum - salmonella-typhimurium - modeling inactivation - thermal inactivation - mild pasteurization
    Pulsed electrical field (PEF) technology can be used for the inactivation of micro-organisms and therefore for preservation of food products. It is a mild technology compared to thermal pasteurization because a lower temperature is used during processing, leading to a better retention of the quality. In this study, pathogenic and spoilage micro-organisms relevant in refrigerated fruit juices were studied to determine the impact of process parameters and juice composition on the effectiveness of the PEF process to inactivate the micro-organisms. Experiments were performed using a continuous-flow PEF system at an electrical field strength of 20kV/cm with variable frequencies to evaluate the inactivation of Salmonella Panama, Escherichia coli, Listeria monocytogenes and Saccharomyces cerevisiae in apple, orange and watermelon juices. Kinetic data showed that under the same conditions, S. cerevisiae was the most sensitive micro-organism, followed by S. Panama and E. coli, which displayed comparable inactivation kinetics. L. monocytogenes was the most resistant micro-organism towards the treatment conditions tested. A synergistic effect between temperature and electric pulses was observed at inlet temperatures above 35°C, hence less energy for inactivation was required at higher temperatures. Different juice matrices resulted in a different degree of inactivation, predominantly determined by pH. The survival curves were nonlinear and could satisfactorily be modeled with the Weibull model.
    Airborne Microorganisms from Livestock Production Systems and Their Relation to Dust
    Zhao, Y. ; Aarnink, A.J.A. ; Jong, M.C.M. de; Groot Koerkamp, P.W.G. - \ 2014
    Critical Reviews in Environmental Science and Technology 44 (2014)10. - ISSN 1064-3389 - p. 1071 - 1128.
    mouth-disease virus - swine confinement buildings - respiratory-syndrome virus - escherichia-coli o157-h7 - bacterial aerosol samplers - space-charge system - particle deposition rates - negative air ionization - ozone-olefin mixtures - environmental-factors
    Large amounts of airborne microorganisms are emitted from livestock production. These emitted microorganisms may associate with dust, and are suspected to pose a risk of airborne infection to humans in vicinity and to animals on other farms. However, the extent to which airborne transmission may play a role in the epidemic, and how dust acts as a carrier of microorganisms in the transmission processes is unknown. This paper presents the current knowledge of the entire process of airborne transmission of microorganisms - from suspension, transportation until deposition and infection - and their relation to dust. The sampling and the mitigation techniques of airborne microorganisms and dust in livestock production systems are introduced as well.
    The Antimicrobial Activity of the Essential Oil of Pistacia lentiscus var. Chia
    Gkogka, E. ; Hazeleger, W.C. ; Posthumus, M.A. ; Beumer, R.R. - \ 2013
    Journal of Essential Oil Bearing Plants 16 (2013)6. - ISSN 0972-060X - p. 714 - 729.
    plant essential oils - tea tree oil - escherichia-coli o157-h7 - helicobacter-pylori - mastic gum - listeria-monocytogenes - chemical-composition - in-vitro - antibacterial activity - staphylococcus-aureus
    The essential oil of the resin of Pistacia lentiscus var. Chia (mastic oil) was studied in vitro against a wide range of foodborne pathogenic and spoilage microorganisms with a diffusion and a dilution method. Furthermore its chemical composition was analyzed by means of Gas Chromatography-Mass Spectrometry (GC-MS) and the possibility of using the essential oil in food preservation was discussed. The Minimal Inhibitory Concentrations (MICs) of mastic oil were estimated for 6 species of bacteria (Bacillus cereus, Campylobacter jejuni, Clostridium perfringens, Escherichia coli, Salmonella Typhimurium, Staphylococcus aureus), 2 species of yeasts (Saccharomyces cerevisiae and Zygosaccharomyces bailii) and 3 species of fungi (Penicillium roquefortii, Aspergillus flavus and Eurotium amstelodami). GC-MS analysis revealed a chemotype dominated by monoterpenes, principally alpha-pinene and beta-myrcene comprising more than 90 % of the mastic oil. Both methods showed Cl. perfringens as the most susceptible microorganism followed by S. cerevisiae and Z. bailii. With the exception of C. jejuni, Gram-positive were found to be more susceptible to the essential oil than Gram-negative microorganisms and all fungi appeared very resistant to mastic oil. Based on the observed MICs, the contribution of mastic oil to the preservation of bakery/confectionary products at the amounts currently used for flavoring purposes is likely to be negligible.
    Characterization by culture-dependent and culture-1 independent methods of the 2 bacterial population of suckling-lamb packaged in different atmospheres
    Oses, S.M. ; Diez, A.M. ; Melero, B. ; Luning, P.A. ; Jaime, I. ; Rovira, J. - \ 2013
    Food Microbiology 36 (2013)2. - ISSN 0740-0020 - p. 216 - 222.
    spoilage-related microbiota - escherichia-coli o157-h7 - korean fermented seafood - european quality label - sp-nov. - shelf-life - molecular characterization - processing plants - virulence genes - healthy sheep
    This study offers insight into the dynamics of bacterial populations in fresh cuts of suckling lamb under four different atmospheric conditions: air (A), and three Modified Atmosphere Packaging (MAP) environments, 15%O2/30%CO2/55%N2 (C, commercial), 70%O2/30%CO2 (O), and 15%O2/85%CO2 (H) for 18 days. Microbial analyses by both conventional methods and PCR-DGGE were performed. Controversial and surprising results emerged from comparing both methods in relation to the genus Pseudomonas. Thus, conventional methods detected the presence of high numbers of Pseudomonas colonies, although PCR-DGGE only detected this genus in air-packaged samples. PCR-DGGE detected higher microbial diversity in the control samples (A) than in the modified atmospheres (C, O, H), having atmosphere H the fewest number of species. Brochothrix thermosphacta, LAB (Carnobacterium divergens and Lactobacillus sakei), and Escherichia spp. were detected in all the atmospheres throughout storage. Moreover, previously undescribed bacteria from lamb meat such as Enterobacter hormaechei, Staphylococcus equorum and Jeotgalicoccus spp. were also isolated in this study by DGGE. Additionally, qPCR analysis was used to detect and characterize strains of Escherichia coli. Virulence genes (stx1, stx2 and eae) were detected throughout storage in 97% of the samples. A high CO2 atmosphere was the most effective packaging combination doubling storage time in comparison with commercial atmosphere.
    Context factors affecting design and operation of Food Safety Management Systems in the fresh produce chain
    Kirezieva, K.K. ; Nanyunja, J. ; Jacxsens, L. ; Vorst, J.G.A.J. van der; Uyttendaele, M. ; Luning, P.A. - \ 2013
    Trends in Food Science and Technology 32 (2013)2. - ISSN 0924-2244 - p. 108 - 127.
    escherichia-coli o157-h7 - techno-managerial approach - critical control point - pesticide-residues - microbiological quality - salmonella-enterica - modified atmosphere - agricultural soils - irrigation water - fruit juices
    Recent food-borne outbreaks and cases of non-compliances to maximum residue limits of pesticides, indicated that food safety management systems (FSMS) in fresh produce chain are not yet performing in a satisfactory manner. However, the system output is not only dependent on the system design and operation but also on the context wherein it operates. The major context factors that create risk to decision-making in FSMS in the fresh produce chain have been defined in this study, and a tool was developed for their systematic analysis. The tool supports a differentiated assessment of context riskiness, enabling actors in fresh produce chains to take measures in their FSMS or reduce riskiness in the context. The tool can be used at primary production, processing, and trade, and can thus provide insights in the changes of context riskiness over the supply chain. It enables systematic analysis of the context in a product group, sector, or country.
    Modeling the impact of the indigenous microbial population on the maximum population density of Salmonella on alfalfa
    Rijgersberg, H. ; Nierop Groot, M.N. ; Tromp, S.O. ; Franz, E. - \ 2013
    World Journal of Microbiology and Biotechnology 29 (2013)7. - ISSN 0959-3993 - p. 1301 - 1305.
    escherichia-coli o157-h7 - listeria-monocytogenes - predictive microbiology - ground-beef - growth - temperature - survival - sprouts - storage - microflora
    Within a microbial risk assessment framework, modeling the maximum population density (MPD) of a pathogenic microorganism is important but often not considered. This paper describes a model predicting the MPD of Salmonella on alfalfa as a function of the initial contamination level, the total count of the indigenous microbial population, the maximum pathogen growth rate and the maximum population density of the indigenous microbial population. The model is parameterized by experimental data describing growth of Salmonella on sprouting alfalfa seeds at inoculum size, native microbial load and Pseudomonas fluorescens 2–79. The obtained model fits well to the experimental data, with standard errors less than ten percent of the fitted average values. The results show that the MPD of Salmonella is not only dictated by performance characteristics of Salmonella but depends on the characteristics of the indigenous microbial population like total number of cells and its growth rate. The model can improve the predictions of microbiological growth in quantitative microbial risk assessments. Using this model, the effects of preventive measures to reduce pathogenic load and a concurrent effect on the background population can be better evaluated. If competing microorganisms are more sensitive to a particular decontamination method, a pathogenic microorganism may grow faster and reach a higher level. More knowledge regarding the effect of the indigenous microbial population (size, diversity, composition) of food products on pathogen dynamics is needed in order to make adequate predictions of pathogen dynamics on various food products.
    Low-water activity foods: increased concern as vehicles of foodborne pathogens
    Beuchat, L.R. ; Komitopoulou, E. ; Beckers, H. ; Betts, R.P. ; Bourdichon, F. ; Fanning, S. ; Joosten, H.M.L.J. ; Kuile, B.H. ter - \ 2013
    Journal of Food Protection 76 (2013)1. - ISSN 0362-028X - p. 150 - 172.
    escherichia-coli o157-h7 - powdered infant formula - salmonella-agona infection - eat savoury snack - enterobacter-sakazakii - cronobacter spp. - peanut butter - international outbreak - heat-resistance - milk powder
    Foods and food ingredients with low water activity (aw) have been implicated with increased frequency in recent years as vehicles for pathogens that have caused outbreaks of illnesses. Some of these foodborne pathogens can survive for several months, even years, in low-aw foods and in dry food processing and preparation environments. Foodborne pathogens in low-aw foods often exhibit an increased tolerance to heat and other treatments that are lethal to cells in high-aw environments. It is virtually impossible to eliminate these pathogens in many dry foods or dry food ingredients without impairing organoleptic quality. Control measures should therefore focus on preventing contamination, which is often a much greater challenge than designing efficient control measures for high-aw foods. The most efficient approaches to prevent contamination are based on hygienic design, zoning, and implementation of efficient cleaning and sanitation procedures in the food processing environment. Methodologies to improve the sensitivity and speed of assays to resuscitate desiccated cells of foodborne pathogens and to detect them when present in dry foods in very low numbers should be developed. The goal should be to advance our knowledge of the behavior of foodborne pathogens in low-aw foods and food ingredients, with the ultimate aim of developing and implementing interventions that will reduce foodborne illness associated with this food category. Presented here are some observations on survival and persistence of foodborne pathogens in low-aw foods, selected outbreaks of illnesses associated with consumption of these foods, and approaches to minimize safety risks
    Multiple regression model for thermal inactivation of Listeria monocytogenes in liquid food products
    Lieverloo, J.H.M. ; Roode, M. de; Fox, M.B. ; Zwietering, M.H. ; Wells-Bennik, M.H.J. - \ 2013
    Food Control 29 (2013)2. - ISSN 0956-7135 - p. 394 - 400.
    sublethal heat-shock - escherichia-coli o157-h7 - growth temperature - scott-a - pseudomonas-aeruginosa - salmonella-typhimurium - resistance - milk - ph - thermotolerance
    A multiple regression model was constructed for thermal inactivation of Listeria monocytogenes in liquid food products, based on 802 sets of data with 51 different strains and 6 cocktails of strains published from 1984 to 2010. Significant variables, other than inactivation temperature, were pH, sodium chloride content, sugar content, the temperature of growth or storage before inactivation, in addition to a heat shock before inactivation. The constructed model for thermal inactivation of L. monocytogenes has a reduced variability as these variables are known to influence the thermal resistance (and these are known or controllable in practice). Mean simulation results of inactivation of L. monocytogenes during pasteurisation (20 s, 76 °C) of raw milk (calculated mean level after growth 14 cfu/l) were comparable with results of a single regression model constructed from inactivation data found in experiments in milk only (175 data sets, 18 strains/cocktails). Both models predicted a probability of survival of less than 1 in a billion litres. The study shows that multiple regression modelling can be used to obtain a model from all data available, with a limited and realistic uncertainty level, while retaining the variability of heat resistance due to the 51 strains and 6 cocktails of strains (unknown and not controllable in practice).
    Food safety management systems performance in the lamb production chain
    Oses, S.M. ; Luning, P.A. ; Jacxsens, L. ; Jaime, I. ; Rovira, J. - \ 2012
    Food Control 25 (2012)2. - ISSN 0956-7135 - p. 493 - 500.
    escherichia-coli o157-h7 - beef processing plants - haccp-based approach - lactic-acid - steam pasteurization - pathogenic bacteria - bovine carcasses - spray washes - supply chain - hot-water
    This study describes a performance measurement of implemented food safety management system (FSMS) along the lamb chain using an FSMS-diagnostic instrument (FSMS-DI) and a Microbiological Assessment Scheme (MAS). Three slaughterhouses, 1 processing plant and 5 butcher shops were evaluated. All the actors along the lamb chain achieved a moderate risky contextual situation, operating in a basic-average FSMS, which was not enough to obtain a good food safety output. Different suggestions are advised for each actor along the lamb chain for improvements towards higher FSMS activity levels or lower risk levels in context characteristics. The combined assessment is a useful tool to identify the possible causes of poor food safety performance in the lamb chain using few sampling locations, saving time and money.
    Multiplex bioanalytical methods for food and environmental monitoreing
    Rebe, S. ; Haasnoot, W. - \ 2011
    TrAC : Trends in Analytical Chemistry 30 (2011)9. - ISSN 0165-9936 - p. 1526 - 1537.
    surface-plasmon resonance - escherichia-coli o157-h7 - beta-lactam antibiotics - salmonella-typhimurium - suspension array - rapid detection - quantum dots - biosensor - bacteria - milk
    Recent advances in miniaturization of analytical systems and newly emerging technologies offer platforms with greater automation and multiplexing capabilities than traditional biological binding assays. Multiplexed bioanalytical techniques provide control agencies and food industries with new possibilities for improved, more efficient monitoring of food and environmental contaminants. This review deals with recent developments in planar-array and suspension-array technologies, and their applications in detecting pathogens, food allergens and adulterants, toxins, antibiotics and environmental contaminants.
    Comparing equivalent thermal, high pressure and pulsed electric field processes for mild pasteurization of orange juice. Part I: Impact on overall quality attributes
    Timmermans, R.A.H. ; Mastwijk, H.C. ; Knol, J.J. ; Quataert, M.C.J. ; Vervoort, L. ; Plancken, I. van der; Hendrickx, M.E. ; Matser, A.M. - \ 2011
    Innovative Food Science and Emerging Technologies 12 (2011)3. - ISSN 1466-8564 - p. 235 - 245.
    escherichia-coli o157-h7 - pectin methyl esterase - citrus juices - shelf-life - food preservation - inactivation - pectinesterase - storage - microorganisms - vegetables
    Mild heat pasteurization, high pressure processing (HP) and pulsed electric field (PEF) processing of freshly squeezed orange juice were comparatively evaluated examining their impact on microbial load and quality parameters immediately after processing and during two months of storage. Microbial counts for treated juices were reduced beyond detectable levels immediately after processing and up to 2 months of refrigerated storage. Quality parameters such as pH, dry matter content and brix were not significantly different when comparing juices immediately after treatment and were, for all treatments, constant during storage time. Quality parameters related to pectinmethylesterase (PME) inactivation, like cloud stability and viscosity, were dependent on the specific treatments that were applied. Mild heat pasteurization was found to result in the most stable orange juice. Results for HP are nearly comparable to PEF except on cloud degradation, where a lower degradation rate was found for HP. For PEF, residual enzyme activity was clearly responsible for changes in viscosity and cloud stability during storage.
    Transition of enteropathogenic and saprotrophic bacteria in the cycle: Animals-excrement-soil-plants-animals
    Kupriyanov, A.A. ; Semenov, A.M. ; Bruggen, A.H.C. van - \ 2010
    Biology Bulletin / Russian Academy of Sciences 37 (2010)3. - ISSN 1062-3590 - p. 263 - 267.
    escherichia-coli o157-h7 - cattle - manure - typhimurium
    The possibility of transition of saprotrophic and enteropathohenic bacterial populations following the chain of naturally related habitats-fodder-animal gastrointestinal tract (GIT)-animals excrement-soil-plants and again animals with a cyclic formation-has been investigated quantitatively. All bacteria used in the experiments have been shown to successfully overcome all the mechanical, physical-chemical, and biological barriers in the food chain and to come out into the environment with a quite high number. It has been demonstrated that the same bacterial population can pass the whole cycle without additional introduction of similar populations from the outside
    Transfer of enteric pathogens to successive habitats as part of microbial cycles
    Semenov, A.M. ; Kupriyanov, A.A. ; Bruggen, A.H.C. van - \ 2010
    Microbial Ecology 60 (2010)1. - ISSN 0095-3628 - p. 239 - 249.
    escherichia-coli o157-h7 - manure-amended soil - salmonella-enterica - serovar typhimurium - indigenous microflora - foodborne illness - dairy farms - survival - contamination - lettuce
    Escherichia coli O157:H7 gfp and Salmonella enterica Typhimurium gfp passed through six successive habitats within a microbial cycle. Pathogen cultures were introduced into cow dung or fodder. Microscopically observed cells and CFUs were monitored in fodder, dung, dung-soil mix, rhizosphere and phyllosphere of cress or oat plants grown in infested dung–soil mix, and in excrements of snails or mice fed with contaminated cress or oat shoots. Both methods were sensitive enough to monitor cells and CFUs throughout the chain. There was a positive correlation between cells and CFUs. Both pathogens declined through the successive habitats, but with unexpected increased densities on plants compared to dung–soil mix. Pathogen densities were higher in the phyllosphere than the rhizosphere of cress, but for oat plants this was reverse. Survival in dung was better after passage through the digestive tract of cows than after introduction of cultures into dung. Positive correlations between pathogens and copiotrophic bacteria (CB) and dissolved organic carbon (DOC) were observed in dung and dung-soil mixtures, but at low DOC contents CB densities were higher than pathogen densities. Thus, the pathogens are able to cycle through different habitats, surviving or growing better at high DOC concentrations, but maintaining population densities that are sufficiently high to cause disease in humans
    Simulation modelling and risk assessment as tools to identify the impact of climate change on microbiological food safety – The case study of fresh produce supply chain
    Jacxsens, L. ; Luning, P.A. ; Vorst, J.G.A.J. van der; Devlieghere, F. ; Leemans, R. ; Uyttendaele, M. - \ 2010
    Food Research International 43 (2010)7. - ISSN 0963-9969 - p. 1925 - 1935.
    minimally processed vegetables - escherichia-coli o157-h7 - agricultural land-use - time rt-pcr - ambient-temperature - iceberg lettuce - cryptosporidium oocysts - foodborne pathogens - contaminated water - future scenarios
    The current quality assurance and control tools and methods to prevent and/or to control microbiological risks associated with fresh produce are challenged due to the following pressures upon the food supply chain, i.e. changing consumption patterns, globalization and climate change. It demonstrates the need for scientific research and development of new and/or improved tools, techniques and practices to adapt the current risk management systems. In this paper, a conceptual research approach is presented to analyse the complexity of the climate change and globalization challenge on the fresh produce supply chain taken as a case study. The factors which affect the vulnerability of the fresh produce chain demand a multidisciplinary research approach. The proposed knowledge-based modelling system is believed to be a most appropriate way to identify problems and to offer solutions to monitor and prevent microbiological food safety risks during all phases of food production and supply. To explore the potential impact of climate change and globalization, baseline information can be obtained by surveillance and performance measurement of implemented food safety management systems. Simulation of climate change scenarios and the logistic chain of fresh produce, along with mathematical models to optimize packaging technology to maintain quality and safety of fresh produce are tools to provide insights in the complex dynamic ecosystem. They are the basis for elaboration of risk assessment studies to scientifically support management options and decisions to new microbiological threats related to globalization and climate change in the fresh produce supply chain. This research concept as such will contribute to develop strategies in order to guarantee the (microbiological) food safety of fresh produce on the long term
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