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Dike O. Ukuku - One of the best experts on this subject based on the ideXlab platform.
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effect of cold storage on survivors and recovery of injured salmonella bacteria on fresh cut pieces prepared from whole melons treated with heat and hydrogen peroxide
Journal of Food Processing and Preservation, 2019Co-Authors: Dike O. Ukuku, Ocen M. Olanya, Sudarsa Mukhopadhyay, Enda A NiemiraAbstract:Cantaloupes and honeydew melons inoculated with 10⁷ CFU/ml Salmonella bacteria were treated with 1.5% of hydrogen peroxide (H₂O₂) at 20°C and minimally treated at 70°C for 3 min before storage at 5, 10, and 20°C. Salmonella bacteria recovered from the Cantaloupe and honeydew melon rind surfaces averaged 4.5 and 3.9 log CFU/cm², respectively, before antimicrobial treatments. Fresh‐cut pieces prepared at each day of storage were immediately placed inside the refrigerator (5°C) while some pieces were left at room temperature (20°C) for 30 and 60 min before refrigeration. After minimal thermal hydrogen peroxide treatments, injured Salmonella on whole Cantaloupes was significantly (p > 0.05) different than honeydew melons. Cold storage of treated melons at 5°C led to significant (p > 0.05) reduction of the injured bacteria and below detection in fresh‐cut pieces even after enrichment process suggesting that minimal thermal antimicrobial processing will reduce transfer of bacteria to fresh‐cut pieces during fresh‐cut preparation. PRACTICAL APPLICATIONS: The results of this study indicate that minimal thermal treatment with 1.5% of hydrogen peroxide at 70°C for 3 min and immediate cold storage of treated whole melons designated for fresh‐cut preparation will reduce transfer of microbial populations from melons rind surfaces to fresh‐cut pieces during fresh‐cut preparation.
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Effect of cold storage on survivors and recovery of injured Salmonella bacteria on fresh‐cut pieces prepared from whole melons treated with heat and hydrogen peroxide
Journal of Food Processing and Preservation, 2019Co-Authors: Dike O. Ukuku, Sudarsan Mukhopadhyay, Ocen M. Olanya, Brendan A NiemiraAbstract:Cantaloupes and honeydew melons inoculated with 10⁷ CFU/ml Salmonella bacteria were treated with 1.5% of hydrogen peroxide (H₂O₂) at 20°C and minimally treated at 70°C for 3 min before storage at 5, 10, and 20°C. Salmonella bacteria recovered from the Cantaloupe and honeydew melon rind surfaces averaged 4.5 and 3.9 log CFU/cm², respectively, before antimicrobial treatments. Fresh‐cut pieces prepared at each day of storage were immediately placed inside the refrigerator (5°C) while some pieces were left at room temperature (20°C) for 30 and 60 min before refrigeration. After minimal thermal hydrogen peroxide treatments, injured Salmonella on whole Cantaloupes was significantly (p > 0.05) different than honeydew melons. Cold storage of treated melons at 5°C led to significant (p > 0.05) reduction of the injured bacteria and below detection in fresh‐cut pieces even after enrichment process suggesting that minimal thermal antimicrobial processing will reduce transfer of bacteria to fresh‐cut pieces during fresh‐cut preparation. PRACTICAL APPLICATIONS: The results of this study indicate that minimal thermal treatment with 1.5% of hydrogen peroxide at 70°C for 3 min and immediate cold storage of treated whole melons designated for fresh‐cut preparation will reduce transfer of microbial populations from melons rind surfaces to fresh‐cut pieces during fresh‐cut preparation.
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Reducing Transfer of Salmonella and Aerobic Mesophilic Bacteria on Melon Rinds Surfaces to Fresh Juice by Washing With Chlorine: Effect of Waiting Period Before Refrigeration of Prepared Juice
Frontiers Media S.A., 2018Co-Authors: Dike O. Ukuku, Sudarsan Mukhopadhyay, Modesto OlanyaAbstract:Cantaloupes, honeydew melons and watermelons inoculated with Salmonella cocktail at 4.5, 3.8, and 3.2 log10 CFU/cm2, respectively, were sanitized with 200 ppm chlorine before rinds removal, cutting, and juice preparation. Efficacy of 200 ppm chlorine in reducing transfer of Salmonella, aerobic mesophilic bacteria, yeast and mold, and Pseudomonas from the melon surfaces to freshly prepared fruit juice was investigated including the effect of waiting period before refrigeration of the juices. The melon juice filtrates were refrigerated immediately or stored at room temperature (~22°C) for 3 and 5 h before refrigeration. Average Salmonella bacteria recovered in fresh melon juice prepared from unwashed whole Cantaloupes, watermelon and honeydew melons was 1.4, 0.5, and 0.4 log10 CFU/ml, respectively. Juices from unwashed inoculated melons had the highest bacterial populations and storage at an abusive temperature of 10°C led to proliferation. Holding these juices at room temperature for 5 h before refrigeration allowed Salmonella bacteria to increase by 0.5–0.8 log in Cantaloupe juice and 0.3–0.5 log in watermelon and honeydew juices. No Salmonella bacteria was determined in fresh juices prepared from melons washed with chlorinated water. The results of this study showed that washing melons with 200 ppm chlorine before juice preparation and immediately refrigerating the juice will minimize the chances of Salmonella proliferation
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appearance and overall acceptability of fresh cut Cantaloupe pieces from whole melon treated with wet steam process
Lwt - Food Science and Technology, 2017Co-Authors: Dike O. Ukuku, David J Geveke, Lee Chau, Andrew B W Bigley, Brendan A NiemiraAbstract:Minimally processed fresh-cut fruits have a limited shelf-life because of deterioration caused by spoilage microflora and changes in physiological processes. Whole melons was inoculated with 107 CFU/ml of Salmonella, Escherichia coli O157:H7 and Listeria monocytogenes to achieve 4.8, 4.5 and 4.1 log CFU/cm2, respectively on melon surfaces. The inoculated melons were treated with a wet steam processing unit for 180 s before fresh-cut preparation. Microbial safety was studied and the overall appearance and acceptability of the fresh-cut pieces were investigated by trained panelists. There were no visual signs of physical damage on all treated Cantaloupe surfaces immediately after treatments and during storage. All fresh-cut pieces from treated Cantaloupes were negative for bacterial pathogens while aerobic mesophilic bacteria were recovered. Appearance and overall acceptability of fresh-cut pieces from treated melons during 6 days at 5 °C were not significantly (p < 0.05) different from control pieces prepared from fresh melons but were significantly (p < 0.05) different from untreated pieces from day 0 under the same storage conditions for 14 days. The results of this study suggests that wet steam treatment of Cantaloupes rind surfaces designated for fresh-cut preparation will enhance the microbial safety of fresh-cut pieces, and the overall acceptability of cut pieces.
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microbial safety and overall quality of Cantaloupe fresh cut pieces prepared from whole fruit after wet steam treatment
International Journal of Food Microbiology, 2016Co-Authors: Dike O. Ukuku, David J Geveke, Lee Chau, Brendan A NiemiraAbstract:Fresh-cut Cantaloupes have been associated with outbreaks of Salmonellosis. Minimally processed fresh-cut fruits have a limited shelf life because of deterioration caused by spoilage microflora and physiological processes. The objectives of this study were to use a wet steam process to 1) reduce indigenous spoilage microflora and inoculated populations of Salmonella, Escherichia coli O157:H7 and Listeria monocytogenes on the surface of Cantaloupes, and 2) reduce the populations counts in Cantaloupe fresh-cut pieces after rind removal and cutting. The average inocula of Salmonella, E. coli O157:H7 and Listeria monocytogenes was 10(7)CFU/ml and the populations recovered on the Cantaloupe rind surfaces after inoculation averaged 4.5, 4.8 and 4.1logCFU/cm(2), respectively. Whole Cantaloupes were treated with a wet steam processing unit for 180s, and the treated melons were stored at 5°C for 29days. Bacterial populations in fresh-cut pieces prepared from treated and control samples stored at 5 and 10°C for up to 12days were determined and changes in color (CIE L*, a*, and b*) due to treatments were measured during storage. Presence and growth of aerobic mesophilic bacteria and Salmonella, E. coli O157:H7 and L. monocytogenes were determined in fresh-cut Cantaloupe samples. There were no visual signs of physical damage on all treated Cantaloupe surfaces immediately after treatments and during storage. All fresh-cut pieces from treated Cantaloupes rind surfaces were negative for bacterial pathogens even after an enrichment process. Steam treatment significantly (p<0.05) changed the color of the fresh-cut pieces. Minimal wet steam treatment of Cantaloupes rind surfaces designated for fresh-cut preparation will enhance the microbial safety of fresh-cut pieces, by reducing total bacterial populations. This process holds the potential to significantly reduce the incidence of foodborne illness associated with fresh-cut fruits.
Brendan A Niemira - One of the best experts on this subject based on the ideXlab platform.
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Effect of cold storage on survivors and recovery of injured Salmonella bacteria on fresh‐cut pieces prepared from whole melons treated with heat and hydrogen peroxide
Journal of Food Processing and Preservation, 2019Co-Authors: Dike O. Ukuku, Sudarsan Mukhopadhyay, Ocen M. Olanya, Brendan A NiemiraAbstract:Cantaloupes and honeydew melons inoculated with 10⁷ CFU/ml Salmonella bacteria were treated with 1.5% of hydrogen peroxide (H₂O₂) at 20°C and minimally treated at 70°C for 3 min before storage at 5, 10, and 20°C. Salmonella bacteria recovered from the Cantaloupe and honeydew melon rind surfaces averaged 4.5 and 3.9 log CFU/cm², respectively, before antimicrobial treatments. Fresh‐cut pieces prepared at each day of storage were immediately placed inside the refrigerator (5°C) while some pieces were left at room temperature (20°C) for 30 and 60 min before refrigeration. After minimal thermal hydrogen peroxide treatments, injured Salmonella on whole Cantaloupes was significantly (p > 0.05) different than honeydew melons. Cold storage of treated melons at 5°C led to significant (p > 0.05) reduction of the injured bacteria and below detection in fresh‐cut pieces even after enrichment process suggesting that minimal thermal antimicrobial processing will reduce transfer of bacteria to fresh‐cut pieces during fresh‐cut preparation. PRACTICAL APPLICATIONS: The results of this study indicate that minimal thermal treatment with 1.5% of hydrogen peroxide at 70°C for 3 min and immediate cold storage of treated whole melons designated for fresh‐cut preparation will reduce transfer of microbial populations from melons rind surfaces to fresh‐cut pieces during fresh‐cut preparation.
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appearance and overall acceptability of fresh cut Cantaloupe pieces from whole melon treated with wet steam process
Lwt - Food Science and Technology, 2017Co-Authors: Dike O. Ukuku, David J Geveke, Lee Chau, Andrew B W Bigley, Brendan A NiemiraAbstract:Minimally processed fresh-cut fruits have a limited shelf-life because of deterioration caused by spoilage microflora and changes in physiological processes. Whole melons was inoculated with 107 CFU/ml of Salmonella, Escherichia coli O157:H7 and Listeria monocytogenes to achieve 4.8, 4.5 and 4.1 log CFU/cm2, respectively on melon surfaces. The inoculated melons were treated with a wet steam processing unit for 180 s before fresh-cut preparation. Microbial safety was studied and the overall appearance and acceptability of the fresh-cut pieces were investigated by trained panelists. There were no visual signs of physical damage on all treated Cantaloupe surfaces immediately after treatments and during storage. All fresh-cut pieces from treated Cantaloupes were negative for bacterial pathogens while aerobic mesophilic bacteria were recovered. Appearance and overall acceptability of fresh-cut pieces from treated melons during 6 days at 5 °C were not significantly (p < 0.05) different from control pieces prepared from fresh melons but were significantly (p < 0.05) different from untreated pieces from day 0 under the same storage conditions for 14 days. The results of this study suggests that wet steam treatment of Cantaloupes rind surfaces designated for fresh-cut preparation will enhance the microbial safety of fresh-cut pieces, and the overall acceptability of cut pieces.
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microbial safety and overall quality of Cantaloupe fresh cut pieces prepared from whole fruit after wet steam treatment
International Journal of Food Microbiology, 2016Co-Authors: Dike O. Ukuku, David J Geveke, Lee Chau, Brendan A NiemiraAbstract:Fresh-cut Cantaloupes have been associated with outbreaks of Salmonellosis. Minimally processed fresh-cut fruits have a limited shelf life because of deterioration caused by spoilage microflora and physiological processes. The objectives of this study were to use a wet steam process to 1) reduce indigenous spoilage microflora and inoculated populations of Salmonella, Escherichia coli O157:H7 and Listeria monocytogenes on the surface of Cantaloupes, and 2) reduce the populations counts in Cantaloupe fresh-cut pieces after rind removal and cutting. The average inocula of Salmonella, E. coli O157:H7 and Listeria monocytogenes was 10(7)CFU/ml and the populations recovered on the Cantaloupe rind surfaces after inoculation averaged 4.5, 4.8 and 4.1logCFU/cm(2), respectively. Whole Cantaloupes were treated with a wet steam processing unit for 180s, and the treated melons were stored at 5°C for 29days. Bacterial populations in fresh-cut pieces prepared from treated and control samples stored at 5 and 10°C for up to 12days were determined and changes in color (CIE L*, a*, and b*) due to treatments were measured during storage. Presence and growth of aerobic mesophilic bacteria and Salmonella, E. coli O157:H7 and L. monocytogenes were determined in fresh-cut Cantaloupe samples. There were no visual signs of physical damage on all treated Cantaloupe surfaces immediately after treatments and during storage. All fresh-cut pieces from treated Cantaloupes rind surfaces were negative for bacterial pathogens even after an enrichment process. Steam treatment significantly (p<0.05) changed the color of the fresh-cut pieces. Minimal wet steam treatment of Cantaloupes rind surfaces designated for fresh-cut preparation will enhance the microbial safety of fresh-cut pieces, by reducing total bacterial populations. This process holds the potential to significantly reduce the incidence of foodborne illness associated with fresh-cut fruits.
Larry R. Beuchat - One of the best experts on this subject based on the ideXlab platform.
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Glove-mediated transfer of Listeria monocytogenes on fresh-cut Cantaloupe.
Food Microbiology, 2020Co-Authors: Larry R. Beuchat, Wei Zhang, Xiangyu DengAbstract:The common use of gloves in retail practices represents a potential route for cross contamination of foodborne pathogens in fresh-cut produce. Using fresh-cut Cantaloupe as a food model, we investigated factors that may influence glove-mediated cross contamination by Listeria monocytogenes and developed mathematical models to illustrate the patterns of transfer during fresh-cutting practices. Contact time (2, 5, 10 s), contact pressure (0.05, 0.18, 0.37 psi), and glove type (nitrile, polyvinyl chloride, polyethylene) did not have a significant effect on transfer of L. monocytogenes from Cantaloupe rind to flesh, or from flesh to flesh. However, glove type appeared to affect L. monocytogenes transfer from the stem scar tissue to Cantaloupe flesh (P = 0.0371). Transfer from rind pieces that had been washed with water was significantly higher than transfer from pieces that had not been washed (P = 0.0006). Predictive modeling and experimental validation suggested that transfer of L. monocytogenes on Cantaloupe flesh persists over 85 pieces through consecutive contacts with a gloved hand. Findings of the study provide new scientific data to aid researchers, retailers, and caterers in safety risk assessments of fresh-cut practices used to prepare Cantaloupes and other produce items.
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infection of Cantaloupe rind with cladosporium cladosporioides and penicillium expansum and associated migration of salmonella poona into edible tissues
International Journal of Food Microbiology, 2005Co-Authors: Glenner M. Richards, Larry R. BeuchatAbstract:Abstract A study was undertaken to determine if the growth of two phytopathogens, Cladosporium cladosporioides and Penicillium expansum, in wounds on Cantaloupe rinds facilitates migration of Salmonella poona into subsurface mesocarp tissues. Wounded sites in Cantaloupe rind were inoculated with S. poona only, S. poona and mold simultaneously, or mold followed by S. poona 3 days later. A cylindrical plug (ca. 3 cm diameter and 4 cm deep) of inoculated tissue extending from the rind surface into edible tissues was removed and cut transversely into four segments (0–1, 1–2, 2–3, and 3–4 cm) representing distances from the rind surface. Regardless of the type of inoculum or the time of storage subsequent to inoculation, the pH of the tissues was significantly higher (P≤0.05) as the distance from the rind surface increased. Test microorganisms and naturally occurring microorganisms on the rind surface which were introduced into internal tissues during wounding, as well as physiological changes in Cantaloupe tissue, contributed to these changes. C. cladosporioides and P. expansum were recovered from the inoculated rind and underlying tissues throughout storage at 20 °C for 10 days. S. poona persisted and grew in wounds on rinds on inoculated Cantaloupe incubated at 20 °C. Recovery of S. poona from tissues 3–4 cm below the inoculated wound supports the hypothesis that it can migrate from the site of inoculation into adjacent mesocarp tissues. Survival and migration of S. poona into the internal tissues of Cantaloupes were enhanced by co-inoculation with C. cladosporioides and, to a lesser extent, P. expansum. Consumption of Cantaloupes from which diseased tissue has been removed is not advisable because S. poona and perhaps other enteric pathogens may still be present in remaining tissues.
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metabiotic associations of molds and salmonella poona on intact and wounded Cantaloupe rind
International Journal of Food Microbiology, 2005Co-Authors: Glenner M. Richards, Larry R. BeuchatAbstract:Abstract Salmonella Poona, a serotype rarely implicated in human infections, has recently caused several Cantaloupe-associated outbreaks of salmonellosis. Metabiotic associations of molds and foodborne pathogens on produce have been reported. We tested proteolytic activity and measured changes in the pH of Cantaloupe rind caused by growth of Alternaria alternata , Cladosporium cladosporioides , Epicoccum nigrum , Geotrichum candidum , and Penicillium expansum . Survival and growth characteristics of Salmonella Poona co-infected with each mold on the surface rind and in wounded rind tissue as affected by temperature were determined. C. cladosporioides , G. candidum , and P. expansum, but not A. alternata and E. nigrum , showed proteolytic activity on agar media containing gelatin and/or casein, with concurrent increases in pH, thus favoring survival and growth of salmonellae. Intact and mechanically wounded tissue of Cantaloupe rinds were inoculated with a five-strain mixture of S . Poona and/or test mold. Five inoculation schemes were used: mold only, S . Poona only, mold and S . Poona simultaneously, mold then S . Poona 3 days later, and S . Poona then mold 3 days later. The pH of Cantaloupe rinds inoculated with molds and stored at 20 °C for 14 days was significantly higher ( P ≤0.05) than on day 0. Only the pH of rinds inoculated with C. cladosporioides or G. candidum was significantly higher ( P ≤0.05) on day 21 than on day 0, when Cantaloupes were stored at 4 °C. An initial population of S . Poona increased from 3.3 log 10 cfu/sample (ca. 7 cm 2 ) of Cantaloupe rind to populations as high as 9.5 log 10 cfu/sample during storage at 20 °C for up 14 days, regardless of co-inoculation with molds. Populations of S . Poona decreased or remained constant at 4 °C for up to 21 days. Results demonstrate that persistence and growth of S. Poona on intact, wounded, and decaying Cantaloupe rind are not markedly affected by the presence of molds.
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Attachment of Salmonella Poona to Cantaloupe rind and stem scar tissues as affected by temperature of fruit and inoculum.
Journal of Food Protection, 2004Co-Authors: Glenner M. Richards, Larry R. BeuchatAbstract:A negative temperature differential between fruits or vegetables and the water in which they are immersed theoretically enhances infiltration of water and any microorganisms it might contain into tissues. The effect of temperature differentials between Cantaloupes and wash water, each at 4 and 30°C, on changes in Cantaloupe weight and populations of Salmonella enterica Poona recovered from rinds and stem scar tissues of Eastern and Western (shipper) types of Cantaloupes was assessed. The percent weight increase in Western Cantaloupes was significantly greater (P ≤ 0.05) than that in Eastern Cantaloupes for all Cantaloupe and inoculum temperature combinations. Salmonella Poona attachment to or infiltration of Eastern but not Western Cantaloupe rind is enhanced when the fruit is at 4°C, compared with 30°C, regardless of the temperature of the immersion suspension. The number of Salmonella Poona cells recovered from rind tissue of Western Cantaloupes at 30°C immersed in inoculum at 30°C was significantly les...
Alejandro Castillo - One of the best experts on this subject based on the ideXlab platform.
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reduction of salmonella enterica serotype poona and background microbiota on fresh cut Cantaloupe by electron beam irradiation
International Journal of Food Microbiology, 2015Co-Authors: Mangesh P Palekar, Joseph E. Maxim, Matthew T Taylor, Alejandro CastilloAbstract:The efficacy of electron beam (e-beam) irradiation processing to reduce Salmonella enterica serotype Poona on surfaces of fresh-cut Cantaloupe, and the impact of e-beam irradiation processing on the numbers of indigenous microorganisms were determined. Additionally, the D10-value for S. Poona reduction on the cut Cantaloupe was also determined. Fresh-cut Cantaloupe pieces, inoculated with S. Poona to 7.8 log10 CFU/g, were exposed to 0.0, 0.7, or 1.5 kGy. Surviving S. Poona, lactic acid bacteria (LAB), and fungi (yeasts, molds) were periodically enumerated on appropriate media over 21 days of storage at 5 °C. Cantaloupe surface pH was measured for irradiated Cantaloupe across the 21 day storage period. To determine the D10-value of S. Poona, Cantaloupe discs were inoculated and exposed to increasing radiation dosages between 0 and 1.06 kGy; surviving pathogen cells were selectively enumerated. S. Poona was significantly reduced by irradiation; immediate reductions following exposure to 0.7 and 1.5 kGy were 1.1 and 3.6 log10 CFU/g, respectively. After 21 days, S. Poona numbers were between 4.0 and 5.0 log10 CFU/g less than untreated samples at zero-time. Yeasts were not reduced significantly (p ≥ 0.05) by e-beam irradiation and grew slowly but steadily during storage. Counts of LAB and molds were initially reduced with 1.5 kGy (p<0.05) but then LAB recovered grew to high numbers, whereas molds slowly declined for irradiated and control samples. Cantaloupe pH declined during storage, with the greatest decrease in untreated control Cantaloupe (p<0.05). The D10-value for S. Poona was determined to be 0.211 kGy, and this difference from the reductions observed in the cut Cantaloupe studies may be due to the more precise dose distribution obtained in the thin and flat Cantaloupe pieces used for the D10-value experiments. The effect of e-beam irradiation at the same doses used in this study was determined in previous studies to have no negative effect in the quality of the cut Cantaloupe. Therefore, incorporation of low dosage ionizing irradiation and consistent application of irradiation processing can significantly improve the microbiological safety of fresh-cut Cantaloupe.
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Effect of chemical sanitizers on Salmonella enterica serovar Poona on the surface of Cantaloupe and pathogen contamination of internal tissues as a function of cutting procedure.
Journal of Food Protection, 2012Co-Authors: Sasi Vadlamudi, Charles Blankenburg, T. Matthew Taylor, Alejandro CastilloAbstract:Survival of Salmonella enterica subsp. enterica serovar Poona on surface and stem scar portions of inoculated Cantaloupe following sanitizer application, transfer of pathogen from the rind to the flesh during cutting, and growth of Salmonella Poona on Cantaloupe cubes over 15 days of refrigerated storage were investigated. Cantaloupes inoculated with a rifampin-resistant strain of Salmonella Poona (107 CFU/ml) for 3 min and dried for 12 h were washed with chlorine (200 mg free chlorine per liter, 3 min), lactic acid (2%, 2 min), or ozone (30 mg/liter, 5 min). Fresh-cut Cantaloupe cubes were prepared by (i) cutting the Cantaloupe and then removing the rind or by (ii) peeling the rind and then cutting the flesh into pieces. The numbers of Salmonella bacteria recovered were higher in the stem scar portion (6.3 ± 0.3 log CFU/cm2) than the surface (4.8 ± 0.2 log CFU/cm2). Surface treatment with tap water or chlorine did not reduce Salmonella numbers, while treatment with lactic acid or ozone reduced Salmonella...
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Salmonella contamination during production of Cantaloupe: a binational study.
Journal of Food Protection, 2004Co-Authors: Alejandro Castillo, Imelda Mercado, Lisa M. Lucia, Y. Martínez-ruiz, J. Ponce De León, Elsa A. Murano, Gary R. AcuffAbstract:Six Cantaloupe farms and packing plants in South Texas (950 Cantaloupe, 140 water, and 45 environmental samples), including the Rio Grande Valley area, and three farms in Colima State, Mexico (300 Cantaloupe, 45 water, and 15 environmental samples), were sampled to evaluate Cantaloupe contamination with Salmonella and Escherichia coli during production and processing. Samples collected from external surfaces of Cantaloupes, water, and the environments of packing sheds on Cantaloupe farms were examined for the presence of Salmonella and E. coli. Of a total of 1,735 samples collected, 31 (1.8%) tested positive for Salmonella. Fifteen Salmonella serotypes were isolated from samples collected in Texas, and nine from samples collected in Colima. Two serotypes (Poona and Oranienburg) that have been associated with three large Salmonella outbreaks in the United States and Canada linked to the consumption of contaminated Cantaloupe were found in water samples collected at four farms (three from the United States). Susceptibility of Salmonella isolates to 10 antimicrobials was evaluated by disk diffusion. Eighty-eight percent of the isolates from the United States and Mexico were pansusceptible to the antimicrobials tested; eight isolates from the United States demonstrated an intermediate susceptibility to streptomycin and only two isolates were resistant to the same antimicrobial. From Mexico, four isolates showed an intermediate susceptibility to streptomycin and one isolate was resistant to nalidixic acid and streptomycin. Repetitive sequence-based PCR analysis of Salmonella isolates helped to trace potential sources of Salmonella contamination in source water and in subsequent water samples obtained after the filtration systems of U.S. and Mexican Cantaloupe farms. No differences could be seen between the levels of Salmonella contamination in melons from both countries.
Glenner M. Richards - One of the best experts on this subject based on the ideXlab platform.
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infection of Cantaloupe rind with cladosporium cladosporioides and penicillium expansum and associated migration of salmonella poona into edible tissues
International Journal of Food Microbiology, 2005Co-Authors: Glenner M. Richards, Larry R. BeuchatAbstract:Abstract A study was undertaken to determine if the growth of two phytopathogens, Cladosporium cladosporioides and Penicillium expansum, in wounds on Cantaloupe rinds facilitates migration of Salmonella poona into subsurface mesocarp tissues. Wounded sites in Cantaloupe rind were inoculated with S. poona only, S. poona and mold simultaneously, or mold followed by S. poona 3 days later. A cylindrical plug (ca. 3 cm diameter and 4 cm deep) of inoculated tissue extending from the rind surface into edible tissues was removed and cut transversely into four segments (0–1, 1–2, 2–3, and 3–4 cm) representing distances from the rind surface. Regardless of the type of inoculum or the time of storage subsequent to inoculation, the pH of the tissues was significantly higher (P≤0.05) as the distance from the rind surface increased. Test microorganisms and naturally occurring microorganisms on the rind surface which were introduced into internal tissues during wounding, as well as physiological changes in Cantaloupe tissue, contributed to these changes. C. cladosporioides and P. expansum were recovered from the inoculated rind and underlying tissues throughout storage at 20 °C for 10 days. S. poona persisted and grew in wounds on rinds on inoculated Cantaloupe incubated at 20 °C. Recovery of S. poona from tissues 3–4 cm below the inoculated wound supports the hypothesis that it can migrate from the site of inoculation into adjacent mesocarp tissues. Survival and migration of S. poona into the internal tissues of Cantaloupes were enhanced by co-inoculation with C. cladosporioides and, to a lesser extent, P. expansum. Consumption of Cantaloupes from which diseased tissue has been removed is not advisable because S. poona and perhaps other enteric pathogens may still be present in remaining tissues.
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metabiotic associations of molds and salmonella poona on intact and wounded Cantaloupe rind
International Journal of Food Microbiology, 2005Co-Authors: Glenner M. Richards, Larry R. BeuchatAbstract:Abstract Salmonella Poona, a serotype rarely implicated in human infections, has recently caused several Cantaloupe-associated outbreaks of salmonellosis. Metabiotic associations of molds and foodborne pathogens on produce have been reported. We tested proteolytic activity and measured changes in the pH of Cantaloupe rind caused by growth of Alternaria alternata , Cladosporium cladosporioides , Epicoccum nigrum , Geotrichum candidum , and Penicillium expansum . Survival and growth characteristics of Salmonella Poona co-infected with each mold on the surface rind and in wounded rind tissue as affected by temperature were determined. C. cladosporioides , G. candidum , and P. expansum, but not A. alternata and E. nigrum , showed proteolytic activity on agar media containing gelatin and/or casein, with concurrent increases in pH, thus favoring survival and growth of salmonellae. Intact and mechanically wounded tissue of Cantaloupe rinds were inoculated with a five-strain mixture of S . Poona and/or test mold. Five inoculation schemes were used: mold only, S . Poona only, mold and S . Poona simultaneously, mold then S . Poona 3 days later, and S . Poona then mold 3 days later. The pH of Cantaloupe rinds inoculated with molds and stored at 20 °C for 14 days was significantly higher ( P ≤0.05) than on day 0. Only the pH of rinds inoculated with C. cladosporioides or G. candidum was significantly higher ( P ≤0.05) on day 21 than on day 0, when Cantaloupes were stored at 4 °C. An initial population of S . Poona increased from 3.3 log 10 cfu/sample (ca. 7 cm 2 ) of Cantaloupe rind to populations as high as 9.5 log 10 cfu/sample during storage at 20 °C for up 14 days, regardless of co-inoculation with molds. Populations of S . Poona decreased or remained constant at 4 °C for up to 21 days. Results demonstrate that persistence and growth of S. Poona on intact, wounded, and decaying Cantaloupe rind are not markedly affected by the presence of molds.
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Attachment of Salmonella Poona to Cantaloupe rind and stem scar tissues as affected by temperature of fruit and inoculum.
Journal of Food Protection, 2004Co-Authors: Glenner M. Richards, Larry R. BeuchatAbstract:A negative temperature differential between fruits or vegetables and the water in which they are immersed theoretically enhances infiltration of water and any microorganisms it might contain into tissues. The effect of temperature differentials between Cantaloupes and wash water, each at 4 and 30°C, on changes in Cantaloupe weight and populations of Salmonella enterica Poona recovered from rinds and stem scar tissues of Eastern and Western (shipper) types of Cantaloupes was assessed. The percent weight increase in Western Cantaloupes was significantly greater (P ≤ 0.05) than that in Eastern Cantaloupes for all Cantaloupe and inoculum temperature combinations. Salmonella Poona attachment to or infiltration of Eastern but not Western Cantaloupe rind is enhanced when the fruit is at 4°C, compared with 30°C, regardless of the temperature of the immersion suspension. The number of Salmonella Poona cells recovered from rind tissue of Western Cantaloupes at 30°C immersed in inoculum at 30°C was significantly les...