Home About us Contact
|
Home About us Contact | ||
|
|
||
Microbial Reduction (microbial + reduction)
Selected AbstractsWhole-Leaf Wash Improves Chlorine Efficacy for Microbial Reduction and Prevents Pathogen Cross-Contamination during Fresh-Cut Lettuce ProcessingJOURNAL OF FOOD SCIENCE, Issue 5 2010Xiangwu Nou Abstract:, Currently, most fresh-cut processing facilities in the United States use chlorinated water or other sanitizer solutions for microbial reduction after lettuce is cut. Freshly cut lettuce releases significant amounts of organic matter that negatively impacts the effectiveness of chlorine or other sanitizers for microbial reduction. The objective of this study is to evaluate whether a sanitizer wash before cutting improves microbial reduction efficacy compared to a traditional postcutting sanitizer wash. Romaine lettuce leaves were quantitatively inoculated with,E. coli,O157:H7 strains and washed in chlorinated water before or after cutting, and,E. coli,O157:H7 cells that survived the washing process were enumerated to determine the effectiveness of microbial reduction for the 2 cutting and washing sequences. Whole-leaf washing in chlorinated water improved pathogen reduction by approximately 1 log unit over traditional cut-leaf sanitization. Similar improvement in the reduction of background microflora was also observed. Inoculated "Lollo Rossa" red lettuce leaves were mixed with noninoculated Green-Leaf lettuce leaves to evaluate pathogen cross-contamination during processing. High level (96.7% subsamples, average MPN 0.6 log CFU/g) of cross-contamination of noninoculated green leaves by inoculated red leaves was observed when mixed lettuce leaves were cut prior to washing in chlorinated water. In contrast, cross-contamination of noninoculated green leaves was significantly reduced (3.3% of subsamples, average MPN ,,0.3 log CFU/g) when the mixed leaves were washed in chlorinated water before cutting. This result suggests that whole-leaf sanitizing washes could be a practical strategy for enhancing the efficacy of chlorine washes for pathogen reduction and cross-contamination prevention. Practical Application:, Freshly cut leafy greens release large amount of organic matter that negatively impact the chlorine washing efficacy. Implementing the primary antimicrobial intervention step of chlorine washing prior to cutting can significantly improve the efficacy of microbial reduction and minimize pathogen cross-contamination. [source] A Continuous High Pressure Carbon Dioxide System for Microbial Reduction in Orange JuiceJOURNAL OF FOOD SCIENCE, Issue 5 2005Dilek Kincal ABSTRACT: A continuous high-pressure carbon dioxide system, run at ambient conditions, was tested on its performance in reducing both natural and inoculated microbial loads. The prototype system continuously processes orange juice with carbon dioxide (CO2) at high pressures. A central composite design was originally used to examine the variables of pressure, residence time, and CO2/juice ratio. For microbial reduction, residence time was the major factor followed by pressure. The CO2/juice ratio showed no influence on microbial load, and in this equipment, was difficult to control. The unit was able to cause a 5-log reduction of the natural flora in spoiled juice, and could attain a 5-log decrease in numbers of pathogenic Escherichia coli O157:H7, Salmonella typhimurium, and Listeriamonocytogenes. No viable cells of E. coli O157:H7 orS. typhimurium were cultured after the treated juices were stored at room temperature (22 °C) for 14 d. Thus, non-thermal pathogen reduction is possible with this system. [source] Bioreductive deposition of palladium (0) nanoparticles on Shewanella oneidensis with catalytic activity towards reductive dechlorination of polychlorinated biphenylsENVIRONMENTAL MICROBIOLOGY, Issue 3 2005Wim De Windt Summary Microbial reduction of soluble Pd(II) by cells of Shewanella oneidensis MR-1 and of an autoaggregating mutant (COAG) resulted in precipitation of palladium Pd(0) nanoparticles on the cell wall and inside the periplasmic space (bioPd). As a result of biosorption and subsequent bioreduction of Pd(II) with H2, formate, lactate, pyruvate or ethanol as electron donors, recoveries higher than 90% of Pd associated with biomass could be obtained. The bioPd(0) nanoparticles thus obtained had the ability to reductively dehalogenate polychlorinated biphenyl (PCB) congeners in aqueous and sediment matrices. Bioreduction was observed in assays with concentrations up to 1000 mg Pd(II) l,1 with depletion of soluble Pd(II) of 77.4% and higher. More than 90% decrease of PCB 21 (2,3,4-chloro biphenyl) coupled to formation of its dechlorination products PCB 5 (2,3-chloro biphenyl) and PCB 1 (2-chloro biphenyl) was obtained at a concentration of 1 mg l,1 within 5 h at 28°C. Bioreductive precipitation of bioPd by S. oneidensis cells mixed with sediment samples contaminated with a mixture of PCB congeners, resulted in dechlorination of both highly and lightly chlorinated PCB congeners adsorbed to the contaminated sediment matrix within 48 h at 28°C. Fifty milligrams per litre of bioPd resulted in a catalytic activity that was comparable to 500 mg l,1 commercial Pd(0) powder. The high reactivity of 50 mg l,1 bioPd in the soil suspension was reflected in the reduction of the sum of seven most toxic PCBs to 27% of their initial concentration. [source] Significance of processes in the near-stream zone on stream water acidity in a small acidified forested catchmentHYDROLOGICAL PROCESSES, Issue 2 2001Jens Fölster Abstract The near-stream zone has received increasing attention owing to its influence on stream water chemistry in general and acidity in particular. Possible processes in this zone include cation exchange, leaching of organic matter and redox reactions of sulphur compounds. In this study the influences of processes in the near-stream zone on the acidity in runoff from a small, acidified catchment in central southern Sweden were investigated. The study included sampling of groundwater, soil water and stream water along with hydrological measurements. An input,output budget for the catchment was established based on data from the International Co-operative Programme on Integrated Monitoring at this site. The catchment was heavily acidified by deposition of anthropogenic sulphur, with pH in stream water between 4·4 and 4·6. There was also no relationship between stream flow and pH, which is indicative of chronic acidification. Indications of microbial reduction of sulphate were found in some places near the stream, but the near-stream zone did not have a general impact on the sulphate concentration in discharging groundwater. The near-stream zone was a source of dissolved organic carbon (DOC) in the stream, which had a median DOC of 6·8 mg L1. The influence on stream acidity from organic anions was overshadowed by the effect of sulphate, however, except during a spring flow episode, when additional organic matter was flushed out and the sulphate-rich ground water was mixed with more diluted event water. Ion exchange was not an important process in the near-stream zone of the Kindla catchment. Different functions of the near-stream zone relating to discharge acidity are reported in the literature. In this study there was even a variation within the site. There is therefore a need for more case studies to provide a more detailed understanding of the net effects that the near-stream zone can have on stream chemistry under different circumstances. Copyright © 2001 John Wiley & Sons, Ltd. [source] Continuous dense-phase CO2 processing of a coconut water beverageINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 4 2009Sibel Damar Summary Effects of dense-phase CO2 (DPCD) on microbial, physical, chemical and sensorial quality of coconut water (CW) beverage were evaluated. Pressure during DPCD treatment was not significant in microbial reduction whereas temperature and % CO2 levels were significant. DPCD-treated (34.5 MPa, 25 °C, 13% CO2, 6 min), heat-pasteurised (74 °C, 15 s) and untreated CW beverages were evaluated during 9 weeks of refrigerated storage (4 °C). Total aerobic bacteria of DPCD and heat-treated samples decreased whereas that of untreated samples increased to >105 CFU mL,1 after 9 weeks. DPCD increased titratable acidity but did not change pH (4.20) and °Brix (6.0). Likeability of DPCD-treated CW was similar to untreated. Heat-treated samples were less liked (, = 0.05) at the beginning of storage. Off flavour and taste-difference-from-control scores of heated samples were higher than DPCD during the first two weeks. DPCD extended shelf life of acidified, sweetened and carbonated CW over 9 weeks at 4 °C. [source] Antimicrobial finishing of regular and modified nylon-6 fabricsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2008S. E. Shalaby Abstract A simple, efficient, and practically applicable functional approach for improvement antimicrobial properties of nylon-6 fabrics and increase the washing durability of biofunctions was developed. This finishing approach is based on grafting of the fabrics with methacrylic acid (MAA) to create additional carboxylic groups in nylon-6 macromolecules, followed by subsequent reaction with dimethylalklbenzyl ammonium chloride (DMABAC) solution under alkaline conditions. The carboxylic groups react with cationic agent through ionic interaction, which led to the immobilization of QAS on nylon-6 fabrics. This immobilization was proofed through determination of nitrogen content, applying scanning electron microscopy (SEM), and FTIR microscopy. The effect of treatment conditions on salt uptake (SUT) on nylon-6 fabrics and reaction efficiency (RE) was investigated. The antimicrobial assessment of regular and grafted with PMAA nylon-6 fabrics treated with DMABAC revealed that both types of fabrics are characterized before washing, by quite strong biocide effect on Bacillus mycoides, Escherichia coli and Candida albicans. The role of grafting nylon-6 fabrics before treatment with salt on durability of antimicrobial functions seems to be more significant as the samples were repeatedly washed. Even after Laundring 10 times the grafted samples could still provide 80%, 100%, and 87.5% microbial reduction against B. mycoides, E. coli and C. albicans, respectively, in contrast with 42.6%, 65.6%, and 42.5% in case of regular nylon-6 fabrics. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008. [source] Changes in subgingival microflora and humoral immune response following periodontal therapyJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 8 2001I. B. Darby Abstract Objectives: To investigate the effect of scaling and root planing (SRP) on the microflora and humoral immune response in adult periodontitis. Materials & Methods: Clinical measurements, subgingival plaque samples, gingival crevicular fluid and sera were taken from 4 sites in 28 adult periodontitis patients before and after SRP. Polymerase chain reaction was used to determine the presence of A. actinomycetemcomitans, P. gingivalis,B. forsythus, P. intermedia, and T. denticola. ELISA was used to investigate the systemic and local antibody titres to these organisms, and thiocyanate dissociation for the determination of serum antibody avidity. Results: SRP produced a good clinical improvement. On a subject basis there was little significant change in the microflora. However, on a site basis, there were significant reductions in P. intermedia, B. forsythus and T. denticola. There was little change in systemic and local antibody titres following SRP, although there was a significant reduction in antibody avidity to P. gingivalis and P. intermedia Conclusion: Post-therapy clinical improvement was associated with a reduction in bacterial prevalence, but statistical significance was only reached at a site level and this microbial reduction was not significant for all organisms. No significant post-therapy effects on the humoral immune response were noted other than a reduced antibody avidity to P. gingivalis and P. intermedia. The lack of a clear pattern in the humoral immune response may reflect a failure of the host response to produce adequate levels of biologically functional antibodies, and complex interactions between the subgingival flora and the host response. Zusammenfassung Ziele: Untersuchung des Effektes von Scaling und Wurzelglättung (SRP) auf die Mikroflora und menschliche Immunantwort bei der Erwachsenen-Parodontitis. Material und Methoden: Klinische Messungen, subgingivale Plaqueproben, gingivale Sulkusflüssigkeit und Serum wurden von 4 Flächen bei 28 Patienten mit Erwachsenen-Parodontitis vor und nach SRP aufgenommen. Die Polymerase-Ketten-Reaktion wurde genutzt, um die Präsenz von A. actinomycetemcomitans, P. gingivalis, B. forsythus, P. intermedia und T. denticola zu bestimmen. ELISA wurde für die Bestimmung der systemischen und lokalen Antikörpertiter gegen diese Organismen genutzt. Die Thiocyanat-Dissoziation wurde für die Bestimmung der Serumantikörperaktivitart genutzt. Ergebnisse: SRP erbrachte eine gute klinische Verbesserung. Auf der Basis der Person gab es eine geringe signifikante Veränderung der Mikroflora. Jedoch gab es auf der Basis der Fläche eine signifikante Reduktion von P. intermedia, B. forsythus und T. denticola. Geringe Veränderungen in den systemischen und lokalen Antikörpertitern in der Folge von SRP waren zu beobachten, obwohl eine signifkante Reduktion der Antikörperaktivität zu P. gingivalis und P. intermedia vorhanden war. Schlußfolgerung: Die posttherapeutischen klinischen Verbesserungen waren mit einer Reduktion der bakteriellen Prävalenz verbunden, die statistische Signifikanz wurde aber nur auf der Basis der Fläche erreicht, und diese mikrobielle Reduktion war nicht signifikant für alle Organismen. Keine signifikanten posttherapeutischen Effekte auf die menschliche Immunantwort wurden außer einer reduzierten Antikörperaktivität zu P. gingivalis und P. intermedia beobachtet. Der Mangel in einem klaren Muster in der menschlichen Immunantwort könnte einen Fehler in der Wirtsantwort zur Produktion adäquater Level von biologisch funktionellen Antikörpern und komplexen Interaktionen zwischen der subgingivalen Flora und der Wirtsantwort reflektieren. Résumé But: L'objectif de cette étude est de rechercher les effets du détartrage et du surfaçage radiculaire (SRP) sur la microflore et la réponse immunitaire humorale chez des patients atteints de parodontite de l'adulte. Méthodes: Les mesures cliniques, les échantillons de plaque sous-gingivale, le fluide gingivale et le serum ont été prélevés sur 4 sites chez 28 patients atteints de parodontite de l'adulte avant et après SRP. La réaction de polymérase en chaine a été utilisé pour déterminer la présence de Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Bacteroides forsythus, Prevotella intermedia et Treponema denticola. Le test ELISA a été utilisé pour rechercher les titres d'anticorps locaux et systèmiques vis à vis de ces organismes, et la dissociation au thiocyanate a été utilisée pour la détermination de l'avidité des anticorps sériques. Résultats: SRP entrainait une bonne amélioration clinique. Individuellement par patient, il y avait peu de modifications de la microflore. Cependant, en ce qui concerne les sites, il y avait des réductions significatives de Prevotella intermedia, Bacteroides forsythus et Treponema denticola. Il y avait peu de changements pour les titres d'anticorps systèmiques et locaux suite au SRP, bien que l'on observait une réduction significative de l'avidité des anticorps envers Porphyromonas gingivalis et Prevotella intermedia. Conclusions: L'amélioration clinique consécutive au traitement était associée avec une réduction de la prévalence bactérienne, mais une signification statistique n'était obtenue que pour les sites, et cette réduction microbienne n'était pas significative pour tous les organismes. Suite au traitement, aucun effet significatif sur la réponse immunitaire humorale n'était mis en évidence, en dehors de la diminution de l'avidité des anticorps vis à vis de Porphyromonas gingivalis et Prevotella intermedia. L'absence de caractéristiques nettes de la réponse immunitaire humorale pourrait reflèter l'échec de la réponse de l'hôte à produire des niveaux suffisants d'anticorps biologiquement fonctionnels, et également les interactions complexes entre la flore sous-gingivale et cette réponse de l'hôte. [source] Whole-Leaf Wash Improves Chlorine Efficacy for Microbial Reduction and Prevents Pathogen Cross-Contamination during Fresh-Cut Lettuce ProcessingJOURNAL OF FOOD SCIENCE, Issue 5 2010Xiangwu Nou Abstract:, Currently, most fresh-cut processing facilities in the United States use chlorinated water or other sanitizer solutions for microbial reduction after lettuce is cut. Freshly cut lettuce releases significant amounts of organic matter that negatively impacts the effectiveness of chlorine or other sanitizers for microbial reduction. The objective of this study is to evaluate whether a sanitizer wash before cutting improves microbial reduction efficacy compared to a traditional postcutting sanitizer wash. Romaine lettuce leaves were quantitatively inoculated with,E. coli,O157:H7 strains and washed in chlorinated water before or after cutting, and,E. coli,O157:H7 cells that survived the washing process were enumerated to determine the effectiveness of microbial reduction for the 2 cutting and washing sequences. Whole-leaf washing in chlorinated water improved pathogen reduction by approximately 1 log unit over traditional cut-leaf sanitization. Similar improvement in the reduction of background microflora was also observed. Inoculated "Lollo Rossa" red lettuce leaves were mixed with noninoculated Green-Leaf lettuce leaves to evaluate pathogen cross-contamination during processing. High level (96.7% subsamples, average MPN 0.6 log CFU/g) of cross-contamination of noninoculated green leaves by inoculated red leaves was observed when mixed lettuce leaves were cut prior to washing in chlorinated water. In contrast, cross-contamination of noninoculated green leaves was significantly reduced (3.3% of subsamples, average MPN ,,0.3 log CFU/g) when the mixed leaves were washed in chlorinated water before cutting. This result suggests that whole-leaf sanitizing washes could be a practical strategy for enhancing the efficacy of chlorine washes for pathogen reduction and cross-contamination prevention. Practical Application:, Freshly cut leafy greens release large amount of organic matter that negatively impact the chlorine washing efficacy. Implementing the primary antimicrobial intervention step of chlorine washing prior to cutting can significantly improve the efficacy of microbial reduction and minimize pathogen cross-contamination. [source] A Continuous High Pressure Carbon Dioxide System for Microbial Reduction in Orange JuiceJOURNAL OF FOOD SCIENCE, Issue 5 2005Dilek Kincal ABSTRACT: A continuous high-pressure carbon dioxide system, run at ambient conditions, was tested on its performance in reducing both natural and inoculated microbial loads. The prototype system continuously processes orange juice with carbon dioxide (CO2) at high pressures. A central composite design was originally used to examine the variables of pressure, residence time, and CO2/juice ratio. For microbial reduction, residence time was the major factor followed by pressure. The CO2/juice ratio showed no influence on microbial load, and in this equipment, was difficult to control. The unit was able to cause a 5-log reduction of the natural flora in spoiled juice, and could attain a 5-log decrease in numbers of pathogenic Escherichia coli O157:H7, Salmonella typhimurium, and Listeriamonocytogenes. No viable cells of E. coli O157:H7 orS. typhimurium were cultured after the treated juices were stored at room temperature (22 °C) for 14 d. Thus, non-thermal pathogen reduction is possible with this system. [source] | ||||||||||