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Yaguang Luo - One of the best experts on this subject based on the ideXlab platform.

  • Effect of the sequential treatment of 1-methylcyclopropene and acidified sodium chlorite on microbial growth and quality of fresh-cut Cilantro
    Postharvest Biology and Technology, 2007
    Co-Authors: Ji Gang Kim, Yaguang Luo, Yang Tao
    Abstract:

    This study investigated the effects of 1-methylcyclopropene and sanitizer (acidified sodium chlorite or sodium hypochlorite), treated alone or in combination, on microbial growth and quality of packaged fresh-cut Cilantro (Coriandrum sativum L.). Cilantro bunches were treated with 1.5 mg L −1 1-methylcyclopropene or air for 18 h at 10 ◦ C. The samples were then cut and washed in tap water, 100 mg L −1 sodium hypochlorite, or 100 mg L −1 acidified sodium chlorite solution for 1 min. The washed Cilantro leaves were centrifugally dried, packaged with 29.2 pmol s −1 m −2 Pa −1 oxygen transmission rate film, and stored at 5 ◦ C for 14 d. Results indicated that 1-methylcyclopropene significantly (P < 0.0001) delayed the decrease in O2 and accumulation of CO2 partial pressures in the headspace of sample packages. Acidified sodium chlorite application significantly reduced initial coliform/Escherichia coli counts (P < 0.001), and reduced decay rate at the end of storage (P < 0.05). A combination treatment of 1-methylcyclopropene and acidified sodium chlorite, followed by acidified sodium chlorite treatment alone, maintained the lowest decay rates and the highest overall quality scores at the end of storage. Published by Elsevier B.V.

  • Microbial reduction and storage quality of fresh-cut Cilantro washed with acidic electrolyzed water and aqueous ozone
    Food Research International, 2004
    Co-Authors: Hua Wang, Hao Feng, Yaguang Luo
    Abstract:

    Efficacy of decontamination treatments in reducing microbial populations on Cilantro and in improving its storage quality was investigated. Fresh-cut Cilantro samples were washed with one of the five treatments: tap water, acidic electrolyzed water (AEW), aqueous ozone, chlorinated water, and aqueous ozone followed by AEW (sequential wash). Treated Cilantro was packaged in polyethylene bags prepared with films of selected oxygen transmission rate of 6200 mL/(d m 2 ) and stored at 0 � C for 14 days. The total aerobic bacterial population, total enterobacteriaceae, electrolyte leakage and sensory qualities were examined every 4 days. Test results indicated that the sequential wash is effective in initial microbial count reduction. This treatment also maintained low microbial growth during storage. However, the higher electrolyte leakage may indicate Cilantro tissue damage in this treatment. Using AEW alone also resulted in moderate control of aerobic bacterial growth during storage. Ozone treatment, on the other hand, achieved the highest overall quality of Cilantro during storage and also maintained the typical Cilantro aroma.

  • Effect of the Combination of MCP and Sanitizer on Storage Life of Fresh-cut Cilantro
    HortScience, 2004
    Co-Authors: Ji Gang Kim, Yaguang Luo, Yang Tao, Kenneth C. Gross
    Abstract:

    The effects of 1-methylcyclopropene (MCP), sanitizer and their combination on ethylene action, microbial growth and storage life of fresh-cut Cilantro were studied. Fresh Cilantro was treated with 1.5 μL·L-1 MCP for 18 hours at 10 °C. The treated and nontreated Cilantro leaves were cut and washed in water, chlorine, and mixed solution of sodium chlorite and citric acid (SANOVA). Samples were dried, packaged with 29.2μmol·kg-1 Pa s oxygen transmission rate films, and stored for 14 days at 5 °C. Results indicated that MCP affected respiration rate of fresh-cut Cilantro and the headspace gas composition (O2 and CO2) of sample packages. The combined treatment had lower tissue electrolyte leakage and ethanol concentration, and delayed color changes during storage. SANOVA and the combination of MCP and SANOVA were effective in reducing aerobic microbial population and coliform population. Samples treated with MCP and SANOVA had good quality with high overall quality score at the end of storage.

Yang Tao - One of the best experts on this subject based on the ideXlab platform.

  • Effect of the sequential treatment of 1-methylcyclopropene and acidified sodium chlorite on microbial growth and quality of fresh-cut Cilantro
    Postharvest Biology and Technology, 2007
    Co-Authors: Ji Gang Kim, Yaguang Luo, Yang Tao
    Abstract:

    This study investigated the effects of 1-methylcyclopropene and sanitizer (acidified sodium chlorite or sodium hypochlorite), treated alone or in combination, on microbial growth and quality of packaged fresh-cut Cilantro (Coriandrum sativum L.). Cilantro bunches were treated with 1.5 mg L −1 1-methylcyclopropene or air for 18 h at 10 ◦ C. The samples were then cut and washed in tap water, 100 mg L −1 sodium hypochlorite, or 100 mg L −1 acidified sodium chlorite solution for 1 min. The washed Cilantro leaves were centrifugally dried, packaged with 29.2 pmol s −1 m −2 Pa −1 oxygen transmission rate film, and stored at 5 ◦ C for 14 d. Results indicated that 1-methylcyclopropene significantly (P < 0.0001) delayed the decrease in O2 and accumulation of CO2 partial pressures in the headspace of sample packages. Acidified sodium chlorite application significantly reduced initial coliform/Escherichia coli counts (P < 0.001), and reduced decay rate at the end of storage (P < 0.05). A combination treatment of 1-methylcyclopropene and acidified sodium chlorite, followed by acidified sodium chlorite treatment alone, maintained the lowest decay rates and the highest overall quality scores at the end of storage. Published by Elsevier B.V.

  • Effect of the Combination of MCP and Sanitizer on Storage Life of Fresh-cut Cilantro
    HortScience, 2004
    Co-Authors: Ji Gang Kim, Yaguang Luo, Yang Tao, Kenneth C. Gross
    Abstract:

    The effects of 1-methylcyclopropene (MCP), sanitizer and their combination on ethylene action, microbial growth and storage life of fresh-cut Cilantro were studied. Fresh Cilantro was treated with 1.5 μL·L-1 MCP for 18 hours at 10 °C. The treated and nontreated Cilantro leaves were cut and washed in water, chlorine, and mixed solution of sodium chlorite and citric acid (SANOVA). Samples were dried, packaged with 29.2μmol·kg-1 Pa s oxygen transmission rate films, and stored for 14 days at 5 °C. Results indicated that MCP affected respiration rate of fresh-cut Cilantro and the headspace gas composition (O2 and CO2) of sample packages. The combined treatment had lower tissue electrolyte leakage and ethanol concentration, and delayed color changes during storage. SANOVA and the combination of MCP and SANOVA were effective in reducing aerobic microbial population and coliform population. Samples treated with MCP and SANOVA had good quality with high overall quality score at the end of storage.

James L Mcevoy - One of the best experts on this subject based on the ideXlab platform.

Maria T Brandl - One of the best experts on this subject based on the ideXlab platform.

  • effect of the surfactant tween 80 on the detachment and dispersal of salmonella enterica serovar thompson single cells and aggregates from Cilantro leaves as revealed by image analysis
    Applied and Environmental Microbiology, 2014
    Co-Authors: Maria T Brandl, Steven Huynh
    Abstract:

    Salmonella enterica has the ability to form biofilms and large aggregates on produce surfaces, including on Cilantro leaves. Aggregates of S. enterica serovar Thompson that remained attached to Cilantro leaves after rigorous washing and that were present free or bound to dislodged leaf tissue in the wash suspension were observed by confocal microscopy. Measurement of S. Thompson population sizes in the leaf washes by plate counts failed to show an effect of 0.05% Tween 80 on the removal of the pathogen from Cilantro leaves 2 and 6 days after inoculation. On the contrary, digital image analysis of micrographs of single cells and aggregates of green fluorescent protein (GFP)-S. Thompson present in Cilantro leaf washes revealed that single cells represented 13.7% of the cell assemblages in leaf washes containing Tween 80, versus 9.3% in those without the surfactant. Moreover, Tween 80 decreased the percentage of the total S. Thompson cell population located in aggregates equal to or larger than 64 cells from 9.8% to 4.4% (P < 0.05). Regression analysis of the frequency distribution of aggregate size in leaf washes with and without Tween 80 showed that the surfactant promoted the dispersal of cells from large aggregates into smaller ones and into single cells (P < 0.05). Our study underlines the importance of investigating bacterial behavior at the scale of single cells in order to uncover trends undetectable at the population level by bacterial plate counts. Such an approach may provide valuable information to devise strategies aimed at enhancing the efficacy of produce sanitization treatments.

  • The salmonella transcriptome in lettuce and Cilantro soft rot reveals a niche overlap with the animal host intestine.
    Applied and environmental microbiology, 2012
    Co-Authors: Danielle Goudeau, Craig T. Parker, Yaguang Zhou, Shlomo Sela, Yulia Kroupitski, Maria T Brandl
    Abstract:

    Fresh vegetables have been recurrently associated with salmonellosis outbreaks, and Salmonella contamination of retail produce has been correlated positively with the presence of soft rot disease. We observed that population sizes of Salmonella enterica serovar Typhimurium SL1344 increased 56-fold when inoculated alone onto Cilantro leaves, versus 2,884-fold when coinoculated with Dickeya dadantii, a prevalent pathogen that macerates plant tissue. A similar trend in S. enterica populations was observed for soft-rotted lettuce leaves. Transcriptome analysis of S. enterica cells that colonized D. dadantii-infected lettuce and Cilantro leaves revealed a clear shift toward anaerobic metabolism and catabolism of substrates that are available due to the degradation of plant cells by the pectinolytic pathogen. Twenty-nine percent of the genes that were upregulated in Cilantro macerates were also previously observed to have increased expression levels in the chicken intestine. Furthermore, multiple genes induced in soft rot lesions are also involved in the colonization of mouse, pig, and bovine models of host infection. Among those genes, the operons for ethanolamine and propanediol utilization as well as for the synthesis of cobalamin, a cofactor in these pathways, were the most highly upregulated genes in lettuce and Cilantro lesions. In S. Typhimurium strain LT2, population sizes of mutants deficient in propanediol utilization or cobalamin synthesis were 10- and 3-fold lower, respectively, than those of the wild-type strain in macerated Cilantro (P < 0.0002); in strain SL1344, such mutants behaved similarly to the parental strain. Anaerobic conditions and the utilization of nutrients in macerated plant tissue that are also present in the animal intestine indicate a niche overlap that may explain the high level of adaptation of S. enterica to soft rot lesions, a common postharvest plant disease.

  • fitness of salmonella enterica serovar thompson in the Cilantro phyllosphere
    Applied and Environmental Microbiology, 2002
    Co-Authors: Maria T Brandl, Robert E Mandrell
    Abstract:

    The epiphytic fitness of Salmonella enterica was assessed on Cilantro plants by using a strain of S. enterica serovar Thompson that was linked to an outbreak resulting from Cilantro. Salmonella serovar Thompson had the ability to colonize the surface of Cilantro leaves, where it was detected by confocal laser scanning microscopy (CLSM) at high densities on the veins and in natural lesions. The population sizes of two common colonizers of plant surfaces, Pantoea agglomerans and Pseudomonas chlororaphis, were 10-fold higher than that of the human pathogen on Cilantro incubated at 22°C. However, Salmonella serovar Thompson achieved significantly higher population levels and accounted for a higher proportion of the total culturable bacterial flora on Cilantro leaves when the plants were incubated at warm temperatures, such as 30°C, after inoculation, indicating that the higher growth rates exhibited by Salmonella serovar Thompson at warm temperatures may increase the competitiveness of this organism in the phyllosphere. The tolerance of Salmonella serovar Thompson to dry conditions on plants at 60% relative humidity was at least equal to that of P. agglomerans and P. chlororaphis. Moreover, after exposure to low humidity on Cilantro, Salmonella serovar Thompson recovered under high humidity to achieve its maximum population size in the Cilantro phyllosphere. Visualization by CLSM of green fluorescent protein-tagged Salmonella serovar Thompson and dsRed-tagged P. agglomerans inoculated onto Cilantro revealed that the human pathogen and the bacterial epiphyte formed large heterogeneous aggregates on the leaf surface. Our studies support the hypothesis that preharvest contamination of crops by S. enterica plays a role in outbreaks linked to fresh fruits and vegetables.

  • an outbreak of salmonella serotype thompson associated with fresh Cilantro
    The Journal of Infectious Diseases, 2001
    Co-Authors: Jennifer Campbell, Roshan Reporter, Jeff Farrar, Robert E Mandrell, S. Abbott, Maria T Brandl, J C Mohleboetani, Benson S Werner
    Abstract:

    : An outbreak of Salmonella serotype Thompson in California was identified through laboratory-based surveillance and investigated with case-control, traceback, and laboratory studies. There were 35 "sporadic" cases and a restaurant-associated outbreak of 41 cases with onset between 6 March and 31 March 1999. Three case patients were hospitalized. A case-control study found a significant association between illness and eating Cilantro at a restaurant (63% of case patients vs. 34% of control subjects; odds ratio, 3.5; 95% confidence interval, 1.1-11.4). Although common distributors of Cilantro were identified, inadequate records prohibited the identification of a single farm supplying Cilantro. At room temperature, Salmonella Thompson grew more rapidly and to a higher concentration on chopped Cilantro, compared with whole-leaf Cilantro. Freshly made salsa (pH 3.4) supported growth of Salmonella Thompson. Cilantro should be served promptly after chopping. Accurate records of the distribution of produce should be available, and bacterial contamination of produce should be prevented in retail and wholesale establishments, in packing sheds, and on farms.

J. Elmore - One of the best experts on this subject based on the ideXlab platform.