Progress 01/01/06 to 12/31/06
Outputs
The effect of gaseous ozone and hot water alone or in combination, on the sensory and microbial quality of cantaloupe melon was investigated. E. coli O157:H7 cell transmission from the rind to edible melon flesh during cutting practices was also investigated. Four different treatments consisting on hot water (75 C/1 min), gaseous ozone (10,000 ppm / 30 min), gaseous ozone supplied of CO2 gas and the combination of hot water and gaseous ozone were evaluated. Sensory quality and growth evolution of aerobic mesophilic and psycrotrophic bacteria, coliforms, moulds and yeast were studied. In general, hot water, gaseous ozone, and the combination of hot water and gaseous ozone were effective reducing total microbial population. The combination of hot water and gaseous ozone was the most effective treatment to control microbial growth achieving 3.9, 5.2, 2.6 and 2.7 log reductions for mesophilic and psichrotrophic bacteria, moulds and coliforms, respectively. However no
significant differences were observed between gaseous ozone and gaseous ozone supplied of CO2 gas. There was no evidence of damage in melons treated with hot water, ozone or their combination and they maintained initial texture and aroma. Therefore, the combination of hot water and gaseous ozone can be an efficient and promising treatment for controlling microbial growth and maintaining sensory quality of melons. In the related research, the effect of gaseous ozone on the sensory and microbial quality of fresh-cut cantaloupes was investigated. Fresh-cut cantaloupes were treated for 30 minutes with 5,000 and 20,000 ppm ozone. Sensory quality and growth evolution of coliforms, Escherichia coli, Pseudomonas fluorescens, molds, yeasts and lactic acid bacteria were studied. Samples treated with ozone maintained an excellent visual quality, taste and firmness during 7 day storage at 5 C. Both gaseous ozone treatment tested (5,000 and 20,000 ppm) were effective on inactivation of all
microbial groups analyzed although 20,000 ppm achieved higher log reductions. Ozone treatments were effective either on no-ripe and ripe fresh-cut melon achieving a higher control of yeasts on no-ripe melon. Inactivation by gaseous ozone of Salmonella inoculated on melon rind was also investigated. Salmonella inactivation was higher for no-ripe than ripe melons achieving until 4.2 and 2.8 initial log reductions, respectively. Inactivation was higher in dry spots than in wet spots achieving 2.8 and 1.4 initial log reductions. Therefore, rapid drying could be one of several potential barriers to persistence of Salmonella on the surface of cantaloupes melons while ripe tissues reduce the efficacy of these gaseous ozone treatments.
Impacts
Multidisciplinary expertise from public institutions, government researchers, and international research collaborators are developing applied science-based options for enhancing the microbial food safety for the melon producer, handler, processor, and consumer. Data demonstrating the low thresholds for potential internalization of contamination during food preparation or processing elevated awareness for all stakeholders of the need for comprehensive prevention programs at all steps along the food chain. New findings and recommendations are being broadly disseminated in refereed journals, on-line bulletins, video training materials and in industry trade journals. Regional workshops are communicating Recommended Management Practices that are being widely adopted into voluntary industry standards to minimize the risks of food borne illness.
Publications
- Maria V. Selma , Ana M. Ibanez, and Trevor Suslow, 2006, Effect of gaseous ozone and hot water on sensory and microbial quality of cantaloupe and potential transference of E. coli O157:H7 during cutting, International Journal of Food Microbiology (submitted)
- Maria V. Selma , Ana M. Ibanez, and Trevor Suslow, 2006, Effectiveness of gaseous ozone on Salmonella disinfection and reduction of endemic microflora on fresh-cut cantaloupe, Journal Food Microbiology
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Progress 09/15/02 to 09/14/06
Outputs
OUTPUTS: The outputs of this project have been widely disseminated among diverse stakeholders and consumers across the full breadth of the melon supply chain. Three regional workshops on microbial food safety for whole and fresh-cut melons were held in Coalinga, CA, Hermosillo, MX and Tifton, GA. Information that was developed collectively by project scientists and sub-awardees was shared in technical sessions and symposia of the IFT, IAFP, United Fresh Produce Assn., PMA, and the Southeastern Fruit and Vegetable Growers Assn. and annually at the UC Postharvest Biology and Technology Shortcourse (week-long course each June) and the UC Fresh-cut Quality and Safety Workshop (3 days each Sept). Additional presentations were made at annual meetings of the National Watermelon Assn. and the National Watermelon Promotion Board. These workshops brought together growers, packers, and handlers of whole and pre-cut melons to hear the research outcomes, regional risk assessment survey outcomes, and practical information for developing and implementing Best Management Practices for Melons. Participants obtained a greater awareness of foodborne illness concerns for melons in a regionally relevant manner as well as an overview and training on issues related to compliance and regulatory surveillance programs for Salmonella and Shigella on cantaloupe. Further outputs include two DVD-video training and information products; one targeting growers and shippers and one for consumer education on melon safety. These were widely distributed to the industry and targeted media by the CA Cantaloupe Advisory Board and are available in full at the YouTube sector of the UC Davis Postharvest Research and Information Center. Over ten company-specific meetings were attended primarily by PI-Suslow, Co-PI Annous, and sub-awardees Hernandez, Cantwell, and Beaulieu during this period to review research outcomes, discuss implications of the research findings to melon quality and safety during production, handling and processing, and discuss opportunities to conduct novel, pilot treatment and shipping studies under incremental funding from new awards. Outputs from these efforts were utilized as input for melon-specific guidance documents produced by produce industry associations and individual companies in the US and Mexico. Though difficult to document due to proprietary constraints of fresh-cut processors, adoption of research outputs in disinfection technologies were implemented to improve food safety performance including commercial pilot-trials or full-scale adoption of vapor heat treatment for rind disinfection, chlorine dioxide, gaseous ozone, and aqueous chlorine dioxide treatment of fresh-cut melons. This project has helped identify key risk factors, practical food safety prevention and management practices and needs to ensure sensory quality for melons. Additional key outputs that have received broad industry attention include an electronic database of peer-reviewed technical papers pertaining to melon food safety and a media and consumer-oriented extension outreach article on proper melon washing in the home and detailed guidance on benefits and pitfalls of pathogen testing. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The broad impacts of this project are largely recognized for major contributions in two key areas; 1) science-based knowledge in risk identification and risk exposure for melon production, packing, distribution, and processing; and 2) parameters affecting the efficacy of single and sequential disinfection treatments including mechanical, energetic, biological, and chemical. As a result of the multi-year, multi-institution, and multi-disciplinary project needed information on cantaloupe, honeydew, and watermelon rind characteristics, biology and ecology of the associated microbiota, biofilm formation and disinfection resistance, and survival and transference characteristics during food preparation were elucidated. These practical outputs rapidly found utility in the formation of Commodity-Specific Guidance developed by industry, government, and ARS or academic researchers including several from this sub-group of the S-294 workgroup. Realistically, the major impacts of this research have been to describe in detail aspects of hazard analysis of preharvest inputs, worker hygiene, postharvest limitations to pathogen removal and inactivation, a high transferability during processing, rapid growth potential of bacterial enteric pathogens on melon flesh, and the many challenges and limitations of emerging technologies for disinfection applied to cantaloupe, as compared to honeydew and watermelon. In particular, the California melon industry, a major supplier for domestic markets, had a vested interest in utilizing the project outcomes as objective, science-based information regarding the frequency of detectable Salmonella contamination of cantaloupes within the normal range of production locations and practices. The impact has been to identify various preventive approaches to minimize the likelihood of contamination, to minimize survival should contamination occur, and develop additional optional postharvest treatments at packing to remove or kill potentially surviving bacterial contaminants. The baseline analysis of pathogen presence or absence and survival at the field level has set expectations and strengthened the developing guidelines being implemented by the CA melon industry. The importance to the industry of this facet of the overall project was to document the lack of detectable thresholds of contamination on the outer rind during production and their predicted removal efficiency in downstream handling to the point of shipping. For the watermelon industry, addressing issues of low pathogen survival under retail distribution conditions and consumer washing and handling guidance were key outcomes that were incorporated into their Good Agricultural and Good Handling Practices Manual. Research conducted by collaborating sub-awardees in Mexico contributed to the broader recognition and acceptance of hazards associated regional irrigation water quality and packing shed management for Salmonella contamination sources. Changes in preventive and sanitation programs have been identified by these collaborators as improving the safety of domestic melons for consumers in Mexico and compliance certification programs for exporters to the US and Canada.
Publications
- Suslow, T. 2004. Minimizing the risk of foodborne illness associated with cantaloupe production and handling in California: Overview of Industry Practices and Risk Assessment. 24pp. available at http:ucgaps.ucdavis.edu and http:ucfoodsafety.ucdavis.edu
- Annous, B.A. et al. Surface pasteurization of whole fresh cantaloupes inoculated with Salmonella Poona or Escherichia coli. Journal of Food Protection 67:1876-1885. 2004. Richards, G.M. and
- Beuchat, L.R. Attachment of Salmonella Poona to cantaloupe rind and stem scar tissues as affected by temperature of fruit and inoculum. Journal of Food Protection 67:1359-1364. 2004.
- Richards, G.M. et al. Survey of yeasts for antagonistic activity against Salmonella Poona in cantaloupe juice and wounds in rinds coinfected with phytopathogenic molds. Journal of Food Protection 67:2132-2142. 2004.
- Ukuku, D.O. Effect of hydrogen peroxide treatment on microbial quality and appearance of whole and fresh-cut melons contaminated with Salmonella spp. International Journal of Food Microbiology 95:137-146. 2004.
- Ukuku, D.O. et al. Method of applying sanitizers and sample preparation affects recovery of native microflora and Salmonella on whole cantaloupe surfaces. Journal of Food Protection 67:999-1004. 2004.
- Ukuku, D.O. et al. Effect of hot water and hydrogen peroxide treatments on survival of Salmonella and microbial quality of whole and fresh-cut cantaloupe. Journal of Food Protection 67:432-437. 2004.
- Annous, B.A. et al. Improved recovery procedure for evaluation of sanitizer efficacy in disinfecting contaminated cantaloupes. Journal of Food Science 70:M242-M247. 2005.
- Annous, B.A. et al. Biofilm formation by Salmonella spp. on cantaloupe melon. Journal of Food Safety 25:276-287. 2005.
- Parnell, T.L. et al. Reducing Salmonella on cantaloupes and honeydew melons using practices applicable to postharvest handling, foodservice, and consumer preparation. International Journal of Food Microbiology 99:59-70. 2005.
- Richards, G.M. and Beuchat, L.R. Infection of cantaloupe rind with Cladosporium caldosporioides and Penicillium expansum, and associated migration of Salmonella Poona in edible tissue. International Journal of Food Microbiology 103:1-10. 2005.
- Suslow, T. 2005. Food Safety DVD: With the Consumer in Mind: Growing, Handling, and Shipping California Cantaloupes. By request from http://ucfoodsafety.ucdavis.edu
- Ukuku, D.O. and Sapers, G.M. Effect of time before storage and storage temperature on survival of Salmonella inoculated on fresh-cut melons. Food Microbiology 24:288-295. 2007.
- Selma, M.V. et al. Effect of gaseous ozone and hot water on microbial and sensory quality of cantaloupe and potential transference of Escherichia coli O157:H7 during cutting. Food Microbiology 25:162-168. 2008.
- Selma, M.V. et al. Reduction by gaseous ozone of Salmonella and microbial flora associated with fresh-cut cantaloupe. Food Microbiology 25:558-565. 2008. Hernandez-Dominguez, C., Hernandez-Anguiano, A.M., Chaidez-Quiroz, C. Rendon-Sanchez , G. and T.V. Suslow. 2008. Detection of Salmonella and fecal coliforms in preharvest and postharvest water applied to cantaloupes in Mexico. Agricultura Tecnica en Mexico vol 34-1 Jan -April
- Suslow, T., Dietrich, F., Uesugi, Bakker, A., and L. Harris. 2009. Survival of Escherichia coli O157:H7, Salmonella spp., and Shigella spp. on Watermelon Surfaces. Manuscript in peer-review
- D'lima, C. and T. Suslow. 2008. Compilation of Research Citations on the Microbiological Safety and Risk Reduction Interventions for Fresh and Fresh-cut Melons. Posted at http://postharvest.ucdavis.edu ; http://cmrb.org/ ,http://www.perishablepundit.com
- Suslow, T. 2008. Salmonella and Cantaloupe: What can consumers really do Posted at http://postharvest.ucdavis.edu ; http://cmrb.org/ http://www.perishablepundit.com
- Hernandez, L.M., Hernandez-Anguiano, A.M.,Chaidez-Quiroz, C., Rendon-Sanchez. G. and T. V. Suslow. 2009. Detection of Salmonella Spp. on Cantaloupe Melon Production Units and Packaging Facility. Agricultura Tecnica en Mexico. 35:135-145
- Suslow, T. 2005. Food Safety DVD: GAP Guidelines for the California Cantaloupe Industry. By request from http://ucfoodsafety.ucdavis.edu
- Dumas,A., Janes, M, and John C. Beaulieu. 2005. Effectiveness of cetylpyridinium chloride dips to reduce foodborne human pathogens Salmonella Montevideo, Shigella sonnei and Escherichia coli on fresh-cut cantaloupe. IFT Annual Mtg. New Orleans. Available at http://ucgaps.ucdavis.edu
- Ukuku, D.O. et al. Use of hydrogen peroxide in combination with nisin, sodium lactate and citric acid for reducing transfer of bacterial pathogens from whole melon surfaces to fresh-cut pieces. International Journal of Food Microbiology 104:225-233. 2005.
- Boynton, B.B. et al. Effects of low-dose electron beam irradiation on respiration, microbiology, texture, color, and sensory characteristics of fresh-cut cantaloupe stored in modified atmosphere packages. Journal of Food Science 71:S149-S155. 2006.
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Progress 01/01/05 to 12/31/05
Outputs
On-going research expanded our characterization of the challenges to removal of Salmonella from the surface of cantaloupes. We have expanded this research, during this period, to assessments of commercial cantaloupe shed pack operations on microbial reductions. Evaluations of shed operations using no disinfectant, hypochlorite, peroxyacetic acid, and ozone have been conducted. The overall approach of this project is to develop practical interventions to disinfect fresh melons and prevent contamination and outgrowth of human pathogens in fresh-cut melon products without adversely affecting product quality or shelf life. The application of chemicals containing chlorine-based agents in vegetable and fruit processing, which can affect human and environmental safety and the increase of outbreaks associated with this commodity, has created the need to investigate other sanitizing alternatives. In the present work, the effect of gaseous ozone and hot water alone or in
combination, on the sensory and microbial quality of cantaloupe melon was investigated. E. coli O157:H7 cell transfer from the rind to edible melon flesh during cutting practices was also investigated. Four different treatments consisting of hot water (75C/1 min), gaseous ozone generated with O2 gas, gaseous ozone and carbon monoxide generated with O2 and CO2 gas, and the combination of hot water and gaseous ozone were evaluated. Sensorial quality, firmness, and growth evolution of aerobic mesophilic bacteria, psychrotrophic bacteria, coliforms, molds and yeast were studied. In general, hot water, gaseous ozone, and the combination of hot water and gaseous ozone were effective reducing total microbial population. The combined treatment resulted in the most effective treatment to control microbial growth by achieving 3.9, 5.2, 2.6 and 2.7 log reductions for mesophilic bacteria, psychrotrophic bacteria, molds, and coliforms, respectively. However no significant differences were observed
between gaseous ozone and gaseous ozone with carbon monoxide. There was no evidence of damage in treated melons and they maintained initial texture and aroma. Therefore, the combination of hot water and gaseous ozone resulted in a promising food safety and spoilage reducing treatment for melons. In addition to scientific journal dissemination of the research outcomes, a lay-technical report and two informational and training DVDs on Good Agricultural Practices (GAPs) for Cantaloupes were released in early 2005. In addition to several research publications and extension presentations from this effort, a program of regional food safety workshops for melons was initiated in 2004, Coalinga, CA July 2004 and an international program in Mexico in November 2005. During this period, some of the key objectives with watermelon were also addressed. The extended survival of Escherichia coli O157:H7, and multistrain mixtures of Salmonella spp., and Shigella spp. was demonstrated on watermelon
surfaces. This capacity to persist on the external surfaces of watermelon underscore the importance of prevention of initial contamination and further reduction interventions prior to processing for consumption.
Impacts
Multidisciplinary expertise from public institutions, government researchers, and international research collaborators are developing applied science-based options for enhancing the microbial food safety for the melon producer, handler, processor, and consumer. Data demonstrating the low thresholds for potential internalization of contamination during food preparation or processing elevated awareness for all stakeholders of the need for comprehensive prevention programs at all steps along the food chain. New findings and recommendations are being broadly disseminated in refereed journals, on-line bulletins, video training materials and in industry trade journals. Regional workshops are communicating Recommended Management Practices that are being widely adopted into voluntary industry standards to minimize the risks of food borne illness.
Publications
- Parnell, T.Lc., L. J. Harrisa, and T. V. Suslow. 2005. Reducing Salmonella on cantaloupes and honeydew melons using wash practices applicable to postharvest handling, foodservice, and consumer preparation. Int. J. Food Microbiol. 99:59-70.
- Suslow, T. 2004. ANR Special Production. Minimizing the risk of foodborne illness associated with cantaloupe production and handling in California: Overview of Industry Practices and Risk Assessment. 24pp Available in hardcopy and online http://ucfoodsafety.ucdavis.edu
- Suslow, T. 2005. Outreach DVD. With the Consumer in Mind: Growing, Handling, and Shipping California Cantaloupes
- Suslow, T. 2005 Outreach DVD. GAP Guidelines for the California Cantaloupe Industry
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Progress 01/01/04 to 12/31/04
Outputs
An opportunity for novel research was initiated during this period that explores a biologically-mediated option for the simultaneous control of postharvest decay pathogens and food-borne human bacterial pathogens on whole melons and potentially fresh cut melons. Research conducted during this period demonstrated the importance of minimizing the growth of superficial fungi on cantaloupe rind to reduce the opportunities for internalization of Salmonella in metabiotic interactions. The opportunity became evident with the first reports that characterized the antimicrobial properties of low molecular weight volatiles, produced on sterile substrate, by the recently described endophytic fungus, Muscodor albus. A substantial and attractive aspect of this potential commercially registered biological agent for postharvest applications is the separation of viable organism from the target consumed commodity. In simple words, unlike other biological control agents for postharvest
pathogens spatial displacement, nutrient competition, and surface or wound colonization are not required for efficacy. This category of biopesticide has been termed a mycofumigant or biofumigant, and for postharvest applications is not applied directly to the target host. While other issues may ultimately be limiting, reluctance to using this biopesticide by producers or shippers, due to consumer concerns for applied microorganisms, should be minimal. The license for marketing and distribution is held by AgraQuest (Davis, CA) and research during Year 2, supported by an ANR Postharvest IPM Workgroup funded project and this USDA CSREES award, is exploring efficacy in disinfection of cantaloupe, honeydew, and watermelon. The compatibility or synergy of biofumigation with existing optimal and sub-optimal postharvest temperature management practices during storage, transportation and distribution of selected commodities has been the first priority. Longer term interests seek to explore
synergy with other postharvest treatments being evaluated by collaborators in the Project, specifically MA/CA shipping of melons. Our further long term interest is to dissect the biological basis for differential inhibition of pathogens and genetic-enhancement or modulation of volatile profile production. Our research progress to date has determined that the mixed volatiles from M. albus have potential for control of wound inoculated Botrytis cinerea, Cladosprium spp. and Geotrichum candidum in vitro and we have initiated studies on melon rind surfaces. We have demonstrated that postharvest storage temperature during biofumigation strongly affects efficacy. We have also shown that M. albus volatiles are biocidal to the bacterial pathogens Salmonella, E. coli O157:H7, Shigella, and Listeria monocytogenes in vitro and in planta. Equally interesting and important for future integrated pathogen control strategies known beneficial microflora are not sensitive to inhibition. This will
afford us the opportunity in the future to explore both the efficacy of combined treatments and the mechanisms of sensitivity and tolerance to mixed or chromatographically isolated fractions of the M. albus volatiles spectrum.
Impacts
Multidisciplinary expertise from public institutions, government researchers, and international research collaborators are developing applied science-based options for enhancing the microbial food safety for the melon producer, handler, processor, and consumer. New findings and recommendations are being broadly disseminated in refereed journals, on-line bulletins, video training materials and in industry trade journals.
Publications
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Progress 01/01/03 to 12/31/03
Outputs
Background: The purpose of this research project is to improve and broaden our understanding of factors contributing to the initial contamination and persistence of human pathogenic Salmonella spp and E. coli O157:H7 on whole and minimally processed cantaloupes, honeydews, and watermelons, in descending order or priority. A multi-institution and international team of scientists are developing standardized protocols towards improving interventions and disinfection strategies. Collaborators are working to understand the role of microbial biofilms on the surface of melons as barriers to disinfection and to innovate novel methods, including combinations of interventions, of pathogen reduction and disinfection of whole and minimally processed melons. Examples of sequential disinfection research include vacuum ozonation, gaseous chlorine dioxide, biofumigation with natural volatiles, and electron-beam irradiation. Within the progress of research, regional extension and
education programs will bring state of the art information to the production, harvest and postharvest handling industries. Progress to Date: An assessment of the comparative strength of attachment of various serotypes of Salmonella to cantaloupe, honeydew, and watermelon have been largely completed. Intraspecies variability in environmental stress tolerance and competitive competencies have been evaluated using ERIC-PCR to differentiate among serotypes. From these preliminary studies, Salmonella serotypes vary significantly in resistance to desiccation and degree of attachment to the outer rind of watermelon, honeydew, and immature cantaloupe. Relative survival and attachment is essentially uniform on mature netted cantaloupe. Disinfection for whole melons has been evaluated using a five strain mixture of nalidixic acid-resistant Salmonella spp on the outer rind surface of cantaloupe following a four-minute exposure to distilled water (control) and five different sanitizers. Log10
reductions in recoverable populations of presumptive Salmonella (nalr) following immersion in water, chlorine, TsunamiT100, NaHCO3, H2O2, ProSanT and H2O2 + lactic acid at 25 degrees C ranged from 1.68 to 3.78, respectively. Other research by the collaborative team addressed the metabiotic association of molds and foodborne pathogens. Co-infections of these molds and Clostridium botulinum, Listeria monocytogenes, or Salmonella has been shown to result in an enhancement of survival and growth of the pathogens, thus increasing the risk of diseases resulting from their consumption. A study was done to determine if co-infection of cantaloupe rind with Salmonella Poona and five molds isolated from cantaloupes causes changes in rates of death or growth of the pathogen. Results demonstrate that survival and growth of S. Poona are not affected by co-infection with molds commonly responsible for decay of cantaloupes. Growth of S. Poona on intact, wounded, and decaying cantaloupe rind at
refrigerated and ambient temperatures is not enhanced by the increase in pH caused by growth and metabolic activities of these molds.
Impacts
Multidisciplinary expertise from public institutions, government researchers, and international research collaborators are developing applied science-based options for enhancing the microbial food safety for the melon producer, handler, processor, and consumer. New findings and recommendations are being broadly disseminated in refereed journals, on-line bulletins, and in industry trade journals.
Publications
- No publications reported this period
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Progress 01/01/02 to 12/31/02
Outputs
Background: Recent multistate outbreaks linked to cantaloupe consumption, from non-domestic sources, in 1997, 1998, 2000, 2001, and 2002 have brought focus and concern for the microbial food safety of melons, particularly cantaloupes. These reoccurring events underscore the need for integrated prevention and control systems, as with any fruit or vegetable consumed without cooking. This project brings together an international team to address fundamentals of contamination at the source, or during handling and preparation, and limitations in the efficacy of current disinfection treatments of melons contaminated with human pathogens. The technical component focuses on improvements and standardization in methodology for evaluating interventions, the impact of factors that limit the performance of treatments, and the evaluation of novel combinations of treatments to overcome these limitations for both whole and fresh cut melons. In addition, the impacts of these
intervention strategies on quality and sensory traits will be determined. Conversely, the impact of current and emerging quality-enhancing treatments on microbial interventions will be evaluated. Progress to Date: An assessment of the comparative strength of attachment of various serotypes of Salmonella to cantaloupe, honeydew, and watermelon are in progress. The influence of time and RH are being studied. The enhancement of an ERIC-PCR system for analysis of the outcome of competitive interactions among serotypes with environmental or postharvest stresses and other pathogens or microbes is in progress. From preliminary studies, Salmonella serotypes vary significantly in resistance to desiccation and degree of attachment to the outer rind of watermelon and immature cantaloupe but relative survival and attachment is essentially uniform on mature netted cantaloupe. In addition, the quantitative potential for transference of external contamination to edible melon flesh is being evaluated
using E. coli and Salmonella isolates transformed with a highly stable plasmid expressing the GFP protein as a visual marker. Thus far, detectable transfer during melon cutting has been shown to be cell density dependent, requiring at least 300 to 500 CFU/cm2 to result in viable detection by non-selectoive enrichment.
Impacts
Multidisciplinary expertise from land grand institutions, government researchers, and international research collaborators will be utilized to direct applied science-based options for enhancing the microbial food safety for the melon producer, handler, and processor. Our broader, overall goal is to validate a set of standard methods for assessing pathogen interventions and mitigation protocols for cantaloupe, honeydew melon, and watermelon and apply these uniform procedures to addressing key knowledge gaps for improved disinfection and optimal quality retention. We anticipate that this approach may serve as a model and template for other researchers to organize commodity or produce category-specific research responses to food safety concerns. New findings and recommendations are being broadly disseminated.
Publications
- SUSLOW, T.V., J. WU, W.F. FETT AND L.J. HARRIS. 2002 Detection and elimination of Salmonella Mbandaka from naturally-contaminated alfalfa seed by treatment with heat or calcium hypochlorite. Journal of Food Protection Vol. 65, No. 3, pp. 452-458
- CANTWELL, M. AND T. SUSLOW. 2002 Postharvest handling systems: fresh cut vegetables for postharvest technology. Postharvest Technology of Horticultural Crops. Pp. 445-463 Third Edition ANR Publication 3311.
- HERNANDEZ, A., T. SUSLOW , L. LELOUP , AND C. I. KADO. 2002 Role of bacterial biosurfactant as a virulence-enhancer in the decay of minimally processed vegetables. Ph. D. Dissertation
- CIFUENTES, R. AND T.V. SUSLOW. 2002 Evaluation of postharvest survival and growth of Salmonella, Escherichia coli, and Listeria on peaches, plums, nectarines, and table grapes. MS Dissertation
- WILSON, M., CAMPBELL, H., , JI, P., JONES, J., KLOEPPER, J., AND T. SUSLOW 2002 Integrated biological control of bacterial speck and spot of tomato under field conditions using foliar biological control agents and plant-growth promoting rhizobacteria. Phytopathology : accepted Nov. 2002
- LINDOW, S., and T. SUSLOW 2002 Temporal dynamics of the biological control agent Pseudomonas fluorescens strain A506 in flowers in inoculated pear trees. Phytopathology : Accepted Dec. 2002
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