| microflora of partially processed lettuce. | bacteria, yeasts, and molds isolated from partially processed iceberg lettuce were taxonomically classified. the majority of bacterial isolates were gram-negative rods. pseudomonas, erwinia, and serratia species were commonly found. yeasts most frequently isolated from lettuce included members of the genera candida, cryptococcus, pichia, torulaspora, and trichosporon. comparatively few molds were isolated; members of the genera rhizopus, cladosporium, phoma, aspergillus, and penicillium were ide ... | 1990 | 2082830 |
| behavior of listeria monocytogenes and aeromonas spp. on fresh-cut produce packaged under equilibrium-modified atmosphere. | storage experiments were conducted to follow the behavior of pathogens on fresh-cut vegetables (trimmed brussels sprouts, grated carrots, shredded iceberg lettuce, and shredded chicory endives) packaged under an equilibrium-modified atmosphere (ema) (2 to 3% o2, 2 to 3% co2, and 94 to 96% n2) and stored at 7 degrees c. as a comparison, fresh-cut vegetables were also packaged in a perforated high-barrier film (air conditions) and stored at 7 degrees c. in a first step, the shelf life of the veget ... | 1999 | 10528715 |
| reveal 8-hour test system for detection of escherichia coli o157:h7 in raw ground beef, raw beef cubes, and iceberg lettuce rinse: collaborative study. | five different food types were analyzed by the reveal for e. coli o157:h7 8-hour test system (reveal 8) and either the u.s. food and drug administration's bacteriological analytical manual (bam) culture method or the u.s. department of agriculture food safety inspection service (fsis) culture method for the presence of e. coli o157:h7. a total of 27 laboratories representing academia and private industry in the united states and canada participated. food types were inoculated with e. coli o157:h ... | 2001 | 11417637 |
| mild heat treatment of lettuce enhances growth of listeria monocytogenes during subsequent storage at 5 degrees c or 15 degrees c. | the objective of this study was to determine the influence of mild heat treatment, storage temperature and storage time on the survival and growth of listeria monocytogenes inoculated onto cut iceberg lettuce leaves. | 2002 | 11849355 |
| occurrence of yersinia pseudotuberculosis in iceberg lettuce and environment. | | 2003 | 12756795 |
| inactivation of escherichia coli o157:h7, salmonella enterica serotype enteritidis, and listeria monocytogenes on lettuce by hydrogen peroxide and lactic acid and by hydrogen peroxide with mild heat. | iceberg lettuce is a major component in vegetable salad and has been associated with many outbreaks of foodborne illnesses. in this study, several combinations of lactic acid and hydrogen peroxide were tested to obtain effective antibacterial activity without adverse effects on sensory characteristics. a five-strain mixture of escherichia coli o157:h7, salmonella enterica serotype enteritidis, and listeria monocytogenes was inoculated separately onto fresh-cut lettuce leaves, which were later tr ... | 2002 | 12182470 |
| penetration of escherichia coli o157:h7 into lettuce as influenced by modified atmosphere and temperature. | the effects of temperature and atmospheric oxygen concentration on the respiration rate of iceberg lettuce and escherichia coli o157:h7 cells attachment to and penetration into damaged lettuce tissues were evaluated. respiration rate of lettuce decreased as the temperature was reduced from 37 to 10 degrees c. reducing the temperature further to 4 degrees c did not affect the respiration rate of lettuce. respiration rate was also reduced by lowering the atmospheric oxygen concentration. lettuce w ... | 2001 | 11726166 |
| survival and growth of escherichia coli o157:h7 inoculated onto cut lettuce before or after heating in chlorinated water, followed by storage at 5 or 15 degrees c. | this study determined the effects of mild heat and chlorine treatment followed by storage for up to 18 days at 5 degrees c or 7 days at 15 degrees c on the survival and growth of escherichia coli o157:h7 inoculated onto fresh-cut iceberg lettuce. the efficacy of treatment with 20 ppm chlorine in killing the pathogen on lettuce at 50 degrees c was determined. treatment of lettuce with 20 ppm chlorine at either 20 or 50 degrees c did not result in significantly greater reductions in populations of ... | 2001 | 11252471 |
| comparison of the attachment of escherichia coli o157:h7, listeria monocytogenes, salmonella typhimurium, and pseudomonas fluorescens to lettuce leaves. | attachment of escherichia coli o157:h7, listeria monocytogenes, salmonella typhimurium, and pseudomonas fluorescens on iceberg lettuce was evaluated by plate count and confocal scanning laser microscopy (cslm). attachment of each microorganism (approximately 10(8) cfu/ml) on the surface and the cut edge of lettuce leaves was determined. e. coli o157:h7 and l. monocytogenes attached preferentially to cut edges, while p. fluorescens attached preferentially to the intact surfaces. differences in at ... | 2000 | 11041147 |
| penetration of escherichia coli o157:h7 into lettuce tissues as affected by inoculum size and temperature and the effect of chlorine treatment on cell viability. | penetration of escherichia coli o157:h7 into iceberg lettuce tissues and the effect of chlorine treatment on cell viability were evaluated. attachment of different inoculum levels (10(9), 10(8), and 10(7) cfu/ml) was examined by determining the number of cells at the surface and the cut edge of lettuce leaves (2 by 2 cm). e. coli o157:h7 attached preferentially to cut edges at all inoculum levels, with greater attachment per cm2 of lettuce at higher inoculum levels. a longer attachment time allo ... | 2000 | 10772206 |
| bactericidal activity of isothiocyanate against pathogens on fresh produce. | the bactericidal activity of allyl and methyl isothiocyanate (aitc and mitc) was tested with a rifampicin-resistant strain of salmonella montevideo and streptomycin-resistant strains of escherichia coil o157:h7 and listeria monocytogenes scott a. iceberg lettuce inoculated with high (10(7) to 10(8) cfu/g) and low (10(3) to 10(4) cfu/g) concentrations of bacterial pathogens was treated with aitc and mitc in sealed containers at 4 degrees c for 4 days. aitc showed stronger bactericidal activity th ... | 2000 | 10643765 |
| survival of enterohemorrhagic escherichia coli o157:h7 in bovine feces applied to lettuce and the effectiveness of chlorinated water as a disinfectant. | bovine feces are a potential vehicle for transmitting enterohemorrhagic escherichia coli o157:h7 to humans. a study was undertaken to determine survival characteristics of e. coli o157:h7 on iceberg lettuce using 0.1% peptone water and bovine feces as carriers for inocula. four levels of inoculum, ranging from 10(0) to 10(5) cfu of e. coli o157:h7 per g of lettuce, were applied. populations surviving on lettuce stored at 4 degrees c were monitored for up to 15 days. regardless of the type of car ... | 1999 | 10456734 |
| an outbreak of shigella sonnei infection associated with consumption of iceberg lettuce. | | 1995 | 8903151 |
| outbreak of shigella sonnei infection traced to imported iceberg lettuce. | in the period from may through june 1994, an increase in the number of domestic cases of shigella sonnei infection was detected in several european countries, including norway, sweden, and the united kingdom. in all three countries epidemiological evidence incriminated imported iceberg lettuce of spanish origin as the vehicle of transmission. the outbreaks shared a number of common features: a predominance of adults among the case patients, the presence of double infections with other enteropath ... | 1995 | 7751364 |
| effects of cattle feeding regimen and soil management type on the fate of escherichia coli o157:h7 and salmonella enterica serovar typhimurium in manure, manure-amended soil, and lettuce. | survival of the green fluorescent protein-transformed human pathogens escherichia coli o157:h7 and salmonella enterica serovar typhimurium was studied in a laboratory-simulated lettuce production chain. dairy cows were fed three different roughage types: high-digestible grass silage plus maize silage (6:4), low-digestible grass silage, and straw. each was adjusted with supplemental concentrates to high and low crude protein levels. the pathogens were added to manure, which was subsequently mixed ... | 2005 | 16204535 |
| inactivation of escherichia coli and listeria monocytogenes on iceberg lettuce by dip wash treatments with organic acids. | to study and compare the efficacy of organic acids and chlorine dipping in inactivation of escherichia coli and listeria monocytogenes on fresh-cut iceberg lettuce. | 2007 | 17576223 |
| prediction of pathogen growth on iceberg lettuce under real temperature history during distribution from farm to table. | the growth of pathogenic bacteria escherichia coli o157:h7, salmonella spp., and listeria monocytogenes on iceberg lettuce under constant and fluctuating temperatures was modelled in order to estimate the microbial safety of this vegetable during distribution from the farm to the table. firstly, we examined pathogen growth on lettuce at constant temperatures, ranging from 5 to 25 degrees c, and then we obtained the growth kinetic parameters (lag time, maximum growth rate (micro(max)), and maximu ... | 2005 | 15979180 |
| accumulation and perchlorate exposure potential of lettuce produced in the lower colorado river region. | the colorado river is contaminated with perchlorate concentrations of 1.5-8 microg/l, an anion linked to thyroid dysfunction. over 90% of the lettuce (lactuca sativa l.) consumed during the winter months in the united states is produced in the lower colorado river region. studies were conducted in this region to survey the potential for lettuce perchlorate accumulation and estimate potential human exposure to perchlorate from lettuce. total uptake of perchlorate in the above-ground plant of iceb ... | 2005 | 15969537 |
| growth and bacteriocin production by lactic acid bacteria in vegetable broth and their effectiveness at reducing listeria monocytogenes in vitro and in fresh-cut lettuce. | the fresh-cut fruit and vegetable industry is searching for alternatives to replace chemical treatments with biopreservative approaches that ensure the safety of the product and fulfil consumer preferences for minimally processed foods. in this study, the use of bacteriocins produced by lactic acid bacteria has been tested as a substitute for chemical disinfection of fresh-cut iceberg lettuce. first, the ability of several non-plant origin bacteriocinogenic strains (nisin z(+), plantaricin c(+), ... | 2007 | 17613374 |
| application of microbial risk assessment to the development of standards for enteric pathogens in water used to irrigate fresh produce. | microbial contamination of the surfaces of cantaloupe, iceberg lettuce, and bell peppers via contact with irrigation water was investigated to aid in the development of irrigation water quality standards for enteric bacteria and viruses. furrow and subsurface drip irrigation methods were evaluated with the use of nonpathogenic surrogates, coliphage prd1, and escherichia coli atcc 25922. the concentrations of hepatitis a virus (hav) and salmonella in irrigation water necessary to achieve a 1:10,0 ... | 2005 | 15895721 |
| growth of listeria monocytogenes on iceberg lettuce and solid media. | the growth of pathogenic bacterium listeria monocytogenes on fresh-cut iceberg lettuce under constant temperatures was modelled in order to investigate microbial safety during distribution of this vegetable. we examined the effects of several incubation temperatures, ranging from 5 to 25 degrees c, on bacterial growth. these data were fitted to the baranyi model and the curves showed a high correlation coefficient at all temperature (r2 > 0.95). in addition, the native bacterial flora of the let ... | 2005 | 15862883 |
| survival of campylobacter jejuni on various fresh produce. | the survival of seven human and two chicken campylobacter jejuni strains, with known penner heat-stable (hs) serotypes and pulsed-field gel electrophoresis (pfge) genotypes, was investigated on fresh-cut iceberg lettuce. in addition, the survival of four selected c. jejuni strains was assessed on cantaloupe pieces, cucumber slices, grated carrot and strawberries. fresh produce was inoculated with 10(5) to 10(7) colony-forming units (cfu) of c. jejuni per gram, and the bacterium was enumerated us ... | 2004 | 15541805 |
| efficacy of chlorine and a peroxyacetic acid sanitizer in killing listeria monocytogenes on iceberg and romaine lettuce using simulated commercial processing conditions. | the efficacy of chlorine (100 microg/ml) and a peroxyacetic acid sanitizer (80 microg/ml; tsunami 100) in killing listeria monocytogenes inoculated at populations of 1 to 2, 2 to 3, and 4 to 5 log cfu/g of iceberg lettuce pieces, shredded iceberg lettuce, and romaine lettuce pieces was determined by treatment conditions simulating those used by a commercial fresh-cut lettuce processor. the lettuce/treatment solution ratio was 1:100 (wt/vol), treatment temperature was 4 degrees c, and total treat ... | 2004 | 15222557 |
| survival and recovery of escherichia coli o157:h7, salmonella, and listeria monocytogenes on lettuce and parsley as affected by method of inoculation, time between inoculation and analysis, and treatment with chlorinated water. | the effects of method for applying inoculum and of drying time after inoculation on survival and recovery of foodborne pathogens on iceberg lettuce and parsley were studied. five-strain mixtures of escherichia coli o157:h7, salmonella, or listeria monocytogenes were applied to lettuce and parsley by dip, spot, or spray inoculation methods. inocula were dried for 2 h at 22 degrees c or for 2 h at 22 degrees c and then 22 h at 4 degrees c before being treated with water (control) or chlorine (200 ... | 2004 | 15222533 |
| influence of variations in methodology on populations of listeria monocytogenes recovered from lettuce treated with sanitizers. | the elimination of listeria monocytogenes inoculated onto a piece of cut iceberg lettuce (3.8 by 3.8 cm) by treatment with chlorinated water (200 micrograms/ml free chlorine) and a 0.5% (wt/vol) solution of fit professional line antibacterial cleaner (fit) was investigated. the efficacy of the two sanitizers was not influenced by the composition of the medium used to culture the l. monocytogenes used in the inocula, the number of strains in the inoculum, or the recovery medium used to enumerate ... | 2004 | 15083726 |
| influence of bovine manure as fertilizer on the bacteriological quality of organic iceberg lettuce. | to investigate the bacteriological quality, and the occurrence of selected pathogenic bacteria from organically grown iceberg lettuce fertilized with bovine manure in the form of compost, firm manure and slurry in a 2-year field trial. | 2004 | 15012817 |
| a widespread outbreak of yersinia pseudotuberculosis o:3 infection from iceberg lettuce. | the vehicles and sources of yersinia pseudotuberculosis infection are unknown. in finland, clinical microbiology laboratories routinely report y. pseudotuberculosis isolations and submit isolates for serotype analysis. in october 1998, the number of serotype o:3 infections increased markedly. | 2004 | 14976592 |
| assessment of control measures to achieve a food safety objective of less than 100 cfu of listeria monocytogenes per gram at the point of consumption for fresh precut iceberg lettuce. | the important new concept of the food safety objective (fso) offers a strategy to translate public health risk into a definable goal such as a specified maximum frequency or concentration of a hazardous agent in a food at the time of consumption that is deemed to provide an appropriate level of health protection. for the foodborne pathogen listeria monocytogenes, there is a proposed fso of < 100 cfu/g in ready-to-eat (rte) products at the time of consumption. fresh precut iceberg lettuce is one ... | 2003 | 12597486 |
| evaluation of household sanitizers for reducing levels of escherichia coli on iceberg lettuce. | diluted solutions of various household sanitizers (apple cider vinegar, white vinegar, bleach, and a reconstituted lemon juice product) were tested for their effectiveness in reducing counts of inoculated escherichia coli and naturally present aerobic, mesophilic bacteria on lettuce. sanitization treatments were carried out at 4 degrees c and at room temperature (ca. 21 degrees c) with and without agitation and at different exposure times (0, 1, 5, and 10 min). of the sanitizers tested, 35% whit ... | 2002 | 12380754 |
| suspending lettuce type influences recoverability and radiation sensitivity of escherichia coli o157:h7. | an outbreak strain of escherichia coli o157:h7 was inoculated onto closely related but structurally distinct types of lettuce (lactuca sativa): boston (butterhead lettuce), iceberg (crisphead lettuce), and green leaf and red leaf (colored variants of looseleaf lettuce). the e. coli o157:h7 was inoculated either onto the surface of cut leaf pieces or into a homogenized leaf suspension. samples were gamma irradiated, and the radiation sensitivity of the inoculated bacteria was expressed as a d-val ... | 2002 | 12233847 |
| intra-laboratory validation of a concentration method adapted for the enumeration of infectious f-specific rna coliphage, enterovirus, and hepatitis a virus from inoculated leaves of salad vegetables. | salad vegetables exposed to fecal contamination may cause outbreaks of hepatitis or gastro-enteritis if they are eaten raw. a procedure, based on elution with phosphate-buffered saline and concentration by filtration through membrane filters, was developed for the recovery of enteric viruses from salad leaves. the method was evaluated using lettuce leaves inoculated with hepatitis a virus (hav), poliovirus, and ms2 bacteriophage. in addition, this method was validated by an intra-laboratory stud ... | 2006 | 16387377 |
| cross-contamination of lettuce with escherichia coli o157:h7. | contamination of produce by bacterial pathogens is an increasingly recognized problem. in march 1999, 72 patrons of a nebraska restaurant were infected with enterohemorrhagic escherichia coli (ehec) o157:h7, and shredded iceberg lettuce was implicated as the food source. we simulated the restaurant's lettuce preparation procedure to determine the extent of possible ehec cross-contamination and growth during handling. ehec inoculation experiments were conducted to simulate the restaurant's cuttin ... | 2002 | 11899044 |
| survival and growth of listeria monocytogenes and escherichia coli o157:h7 in ready-to-eat iceberg lettuce washed in warm chlorinated water. | cut iceberg lettuce inoculated with escherichia coli o157:h7 and listeria monocytogenes before and after washing for 3 min in cold (4 degrees c) and warm (47 degrees c) water containing 100 mg/liter total chlorine was stored at i and 10 degrees c in oxygen-permeable film packages (6,000 to 8,000 cc/m2/24 h). cold chlorinated water was detrimental to the survival of e. coli o157: h7 and l. monocytogenes at both storage temperatures. in contrast, washing in warm chlorinated water favored the growt ... | 2002 | 11899043 |
| evaluation of treatments for elimination of foodborne pathogens on the surface of leaves and roots of lettuce (lactuca sativa l.). | several outbreaks of salmonella and escherichia coli o157:h7 infections have been associated with consumption of leafy greens. questions remain concerning the ability of these pathogens to become internalized within lettuce and spinach tissues. an effective validated surface disinfection method for lettuce is needed before factors affecting internalization of pathogens can be studied. the objective of this study was to develop a surface disinfection method for lettuce leaves and roots. iceberg l ... | 2009 | 19350966 |
| efficacy of chlorine, acidic electrolyzed water and aqueous chlorine dioxide solutions to decontaminate escherichia coli o157:h7 from lettuce leaves. | this study compared the efficacy of chlorine (20-200 ppm), acidic electrolyzed water (50 ppm chlorine, ph 2.6), acidified sodium chlorite (20-200 ppm chlorite ion concentration, sanova), and aqueous chlorine dioxide (20-200 ppm chlorite ion concentration, trinova) washes in reducing populations of escherichia coli o157:h7 on artificially inoculated lettuce. fresh-cut leaves of romaine or iceberg lettuce were inoculated by immersion in water containing e. coli o157:h7 (8 log cfu/ml) for 5 min and ... | 2009 | 19428137 |
| evidence of an antilisterial factor induced by wounding of iceberg lettuce tissues. | to examine the influence of wound-associated reactions in cut iceberg lettuce (lactuca sativa l.) tissues on the fate of listeria monocytogenes. | 2006 | 16478519 |
| efficiency of sodium hypochlorite, fumaric acid, and mild heat in killing native microflora and escherichia coli o157:h7, salmonella typhimurium dt104, and staphylococcus aureus attached to fresh-cut lettuce. | the effect of the disinfectant sodium hypochlorite (naclo), with or without mild heat (50 degrees c) and fumaric acid, on native bacteria and the foodborne pathogens staphylococcus aureus, escherichia coli o157:h7, and salmonella typhimurium dt104 attached to iceberg lettuce leaves was examined. the retail lettuce examined consistently harbored 6 to 7 log cfu/g of native bacteria throughout the study period. inner leaves supported 1 to 2 log cfu/g fewer bacteria than outer leaves. about 70% of t ... | 2006 | 16496572 |
| determination of total aerobic and indicator bacteria on some raw eaten vegetables from wholesalers in ankara, turkey. | the aim of this study was to investigate the bacteriological quality of some raw eaten salad vegetables obtained from wholesalers in ankara, turkey. a total of 180 samples including lettuces, cos lettuce, iceberg lettuce, parsley, dill and carrots were analyzed for total aerobic bacteria, total coliform bacteria and e. coli between january 2004 and april 2004. compact dry media (nissui pharmaceutical co. ltd., japan) were used for bacteriological analysis. outer leaves of lettuce, cos lettuce an ... | 2006 | 16503303 |
| differential killing activity of cetylpyridinium chloride with or without bacto neutralizing buffer quench against firmly adhered salmonella gaminara and shigella sonnei on cut lettuce stored at 4 degrees c. | cetylpyridinium chloride (cpc) activity was quenched with bacto neutralizing buffer on inoculated cut iceberg lettuce. this protocol permitted comparison of the numbers of salmonella gaminara- or shigella sonnei-inoculated cells on lettuce that survived 1 min of cpc treatment. cut lettuce was inoculated with about 6 log of salmonella or 9 log of shigella and stored in whirl-pak bags at 4 degrees c for up to 4 days. loosely adhered pathogen cells were washed off before cpc treatment. firmly adher ... | 2006 | 16786847 |
| lettuce for human consumption collected in costa rica contains complex communities of culturable oxytetracycline- and gentamicin-resistant bacteria. | the present widespread use of antimicrobials in crop farming is based upon their successful application in human medicine. however, recent evidence suggests that the massive anthropogenic release of antimicrobials into the biosphere has selected for resistant bacteria and facilitated the transfer of resistance genes among them. this work deals with the examination of iceberg lettuce collected at 10 farms from two regions in costa rica. farmers from nine sampling sites regularly apply commercial ... | 2006 | 16957206 |
| influence of curli expression by escherichia coli 0157:h7 on the cell's overall hydrophobicity, charge, and ability to attach to lettuce. | curli fibers are produced by some escherichia coli cells in response to environmental stimuli. these extracellular proteins enhance the cell's ability to form biofilms on various abiotic surfaces. e. coli 0157:h7 cells readily attach to a variety of fruit and vegetable surfaces. it is not known whether the expression of curli influences the cell's ability to attach to produce surfaces. in this study, the effect of curli expression on the cell's overall hydrophobicity, charge, and ability to atta ... | 2007 | 17612061 |
| survival of escherichia coli o157:h7 and salmonella enterica serovars typhimurium in iceberg lettuce and the antimicrobial effect of rice vinegar against e. coli o157:h7. | the microbiological safety of fresh produce is a significant concern of consumers and industry. after applying at an inoculated level (about 10(6) cfug(-1)) of e. coli o157:h7 and salmonella enterica serovars typhimurium on shredded iceberg lettuce and water samples individually, they were stored at 4 degrees c for 14 days and 22 degrees c for 7 days to monitor the growth and survival of pathogens. the results showed that at the end of 4 degrees c storage, populations of two pathogens in lettuce ... | 2007 | 17613372 |
| shelf-life extension of fresh-cut iceberg lettuce (lactuca sativa l) by different antimicrobial films. | this study was conducted to investigate the antibacterial activity and shelf-life extension effect of iceberg lettuce packed in bn/pe film. the bn/pe film has a strong microbial suppression effect on pathogenic bacteria such as escherichia coli, salmonella enteritidis, and s. typhimurium. the number of psychrophiles and mesophiles during 5 days of cold storage of fresh-cut iceberg lettuce at 10 degrees c packaged in bn/pe film was strictly suppressed in comparison with other tested films (opp, p ... | 2007 | 18051596 |
| bioprotection of golden delicious apples and iceberg lettuce against foodborne bacterial pathogens by lactic acid bacteria. | lactic acid bacteria were isolated from fresh vegetables and fruit and its ability to inhibit the growth of foodborne human pathogens (escherichia coli, listeria monocytogenes, pseudomonas aeruginosa, salmonella typhimurium, and staphylococcus aureus) was tested using the agar spot assay. eighteen isolates showed a strong antagonistic capacity and were further characterised and identified using 16s rdna sequencing and api 50ch. most of them pertained to leuconostoc spp. and lactobacillus plantar ... | 2008 | 18191266 |
| efficacy of neutral electrolyzed water (new) for reducing microbial contamination on minimally-processed vegetables. | consumption of minimally-processed, or fresh-cut, fruit and vegetables has rapidly increased in recent years, but there have also been several reported outbreaks associated with the consumption of these products. sodium hypochlorite is currently the most widespread disinfectant used by fresh-cut industries. neutral electrolyzed water (new) is a novel disinfection system that could represent an alternative to sodium hypochlorite. the aim of the study was to determine whether new could replace sod ... | 2008 | 18237810 |
| irradiation compared with chlorination for elimination of escherichia coli o157:h7 internalized in lettuce leaves: influence of lettuce variety. | pathogenic bacteria internalized in leaf tissues are not effectively removed by surface treatments. irradiation has been shown to inactivate leaf-internalized bacteria, but many aspects of targeting these protected pathogens remain unknown. bacterial cells of a cocktail mixture of 3 isolates of escherichia coli o157:h7 were drawn into the leaves of iceberg, boston, green leaf, and red leaf lettuce using vacuum perfusion. the inoculated leaves were treated with a 3-min wash with sodium hypochlori ... | 2008 | 18577002 |
| contaminants and microorganisms in dutch organic food products: a comparison with conventional products. | organic products were analysed for the presence of contaminants, microorganisms and antibiotic resistance and compared with those from conventional products. no differences were observed in the fusarium toxins deoxynivalenol and zearalenone in organic and conventional wheat, during both a dry period and a very wet period which promoted the production of these toxins. nitrate levels in head lettuce produced organically in the open field were much lower than those in conventional products. in iceb ... | 2008 | 18608495 |
| bioprotective leuconostoc strains against listeria monocytogenes in fresh fruits and vegetables. | ten leuconostoc mesenteroides and one ln. citreum strains isolated from fresh fruit and vegetables were tested for their antagonistic capacity against listeria monocytogenes. genetic differences among strains were analyzed by random amplified polymorphic dna (rapd). all the isolates clustered together and differed from the type strain ln. mesenteroides atcc 8293 as well as from ln. fallax and ln. citreum. organic acids, hydrogen peroxide and bacteriocins were detected as main inhibition mechanis ... | 2008 | 18625532 |
| inactivation of murine norovirus 1 and bacteroides fragilis infecting phage b40-8 by the use of sodium hypochlorite and peroxyacetic acid as decontaminating agents for shredded iceberg lettuce. | | 2008 | 18831252 |
| irradiation in the production, processing and handling of food. final rule. | the food and drug administration (fda) is amending the food additive regulations to provide for the safe use of ionizing radiation for control of food-borne pathogens, and extension of shelf-life, in fresh iceberg lettuce and fresh spinach (hereinafter referred to in this document as "iceberg lettuce and spinach") at a dose up to 4.0 kilo gray (kgy). this action is in partial response to a petition filed by the national food processors association on behalf of the food irradiation coalition. | 2008 | 18958941 |
| potential of escherichia coli o157:h7 to grow on field-cored lettuce as impacted by postharvest storage time and temperature. | a recent development in iceberg lettuce harvesting is field coring, the technique of removing the outer leaves and the cores of the lettuce heads at the time of harvesting in order to reduce shipping waste and maximize production yield. however, this method may increase the potential for contamination during field procedures and therefore, it is important to evaluate the survival and growth of escherichia coli o157:h7 on pre-cored lettuce under simulated field conditions. using a coring knife ar ... | 2009 | 19019473 |
| inactivation of escherichia coli o157:h7, salmonella typhimurium, and listeria monocytogenes on stored iceberg lettuce by aqueous chlorine dioxide treatment. | inactivation of escherichia coli o157:h7, salmonella typhimurium, and listeria monocytogenes in iceberg lettuce by aqueous chlorine dioxide (clo(2)) treatment was evaluated. iceberg lettuce samples were inoculated with approximately 7 log cfu/g of e. coli o157:h7, s. typhimurium, and l. monocytogenes. iceberg lettuce samples were then treated with 0, 5, 10, or 50 ppm clo(2) solution and stored at 4 degrees c. aqueous clo(2) treatment significantly decreased the populations of pathogenic bacteria ... | 2008 | 19021812 |
| efficacy of myrtle oil against salmonella typhimurium on fresh produce. | the antimicrobial activity of myrtle leaves (myrtus communis) oil was tested against the nalidixic acid resistant strain of salmonella typhimurium atcc 13311. an inoculum (100 microl, ca.10(8) cfu/ml) was deposited on the skin of whole tomatoes and 10 g of shredded iceberg lettuce, dried for 2 h at 22 degrees c and held for 22 h at 4 degrees c before treatments. inoculated iceberg lettuce (3.51-3.99 log cfu/g) and tomatoes (3.47-4.86 log cfu/tomato) were treated with three different washing proc ... | 2009 | 19217679 |
| development of a hierarchical bayesian model to estimate the growth parameters of listeria monocytogenes in minimally processed fresh leafy salads. | the optimal growth rate mu(opt) of listeria monocytogenes in minimally processed (mp) fresh leafy salads was estimated with a hierarchical bayesian model at (mean+/-standard deviation) 0.33+/-0.16 h(-1). this mu(opt) value was much lower on average than that in nutrient broth, liquid dairy, meat and seafood products (0.7-1.3 h(-1)), and of the same order of magnitude as in cheese. cardinal temperatures t(min), t(opt) and t(max) were determined at -4.5+/-1.3 degrees c, 37.1+/-1.3 degrees c and 45 ... | 2009 | 19239977 |
| persistence of escherichia coli on injured iceberg lettuce in the field, overhead irrigated with contaminated water. | fresh produce is increasingly implicated in food-related illnesses. escherichia coli can survive in soil and water and can be transferred onto plant surfaces through farm management practices such as irrigation. a trial was conducted to evaluate the impact of field conditions on e. coli persistence on iceberg lettuce irrigated with contaminated water, and the impact of plant injury on the persistence of e. coli. lettuce heads were injured at 14, 7, 3, 2, 1, and 0 days before inoculation, with un ... | 2009 | 19343931 |
| transfer of escherichia coli o157:h7 to iceberg lettuce via simulated field coring. | the field-core (cut and core) harvesting technique used for iceberg lettuce was evaluated as a potential means of cross-contamination with escherichia coli o157:h7. chlorinated water treatment was evaluated for its efficacy in removing or inactivating the pathogen on the blade portion of the field coring device and on cored lettuce. field coring devices inoculated by immersing blades in soil containing e. coli o157:h7 at 3.74 or 6.57 log cfu/g contained 3.13 and 4.97 log cfu per blade, respectiv ... | 2009 | 19343932 |
| efficacy of sodium hypochlorite and peroxyacetic acid to reduce murine norovirus 1, b40-8, listeria monocytogenes, and escherichia coli o157:h7 on shredded iceberg lettuce and in residual wash water. | the efficiency of sodium hypochlorite (naocl) and peroxyacetic acid (paa) to reduce murine norovirus 1 (mnv-1), a surrogate for human norovirus, and bacteroides fragilis hsp40-infecting phage b40-8 on shredded iceberg lettuce was investigated. the levels of removal of viruses mnv-1 and b40-8 were compared with the reductions observed for bacterial pathogens listeria monocytogenes and escherichia coli o157:h7. two inoculation levels, one with a high organic load and the other containing a 10-fold ... | 2009 | 19517733 |
| internalization of salmonella enterica in leaves is induced by light and involves chemotaxis and penetration through open stomata. | outbreaks of salmonellosis related to consumption of fresh produce have raised interest in salmonella-plant interactions leading to plant colonization. incubation of gfp-tagged salmonella enterica with iceberg lettuce leaves in the light resulted in aggregation of bacteria near open stomata and invasion into the inner leaf tissue. in contrast, incubation in the dark resulted in a scattered attachment pattern and very poor stomatal internalization. forcing stomatal opening in the dark by fusicocc ... | 2009 | 19648358 |
| effectiveness of bacteriophages in reducing escherichia coli o157:h7 on fresh-cut cantaloupes and lettucet. | consumption of produce contaminated with escherichia coli o157:h7 has resulted in cases of foodborne illness. we determined the efficacy of a mixture of three e. coli o157:h7-specific bacteriophages (ecp-100) in reducing the number of viable e. coli o157:h7 on contaminated fresh-cut iceberg lettuce and cantaloupe. e. coli o157:h7 was spot inoculated on lettuce pieces (9 cm2) with a population of 3.76 log cfu/cm2, allowed to dry, and then sprayed with a control (phosphate-buffered saline) or ecp- ... | 2009 | 19681274 |
| efficacy of disinfectants to reduce listeria monocytogenes on precut iceberg lettuce. | the efficacy of water, chlorinated water (100 ppm), peracetic acid solution (0.05%), and commercial citric acid-based produce wash (0.25%) to reduce the population of listeria monocytogenes on precut lettuce was tested. samples were inoculated with a mixture of equal amounts of five l. monocytogenes strains at a level of 4.7 log cfu/g, and analyzed on the day of washing and after 3 and 6 days of storage at 6 degrees c. sanitizer reduced the number of l. monocytogenes at maximum 1.7 log cfu/g and ... | 2006 | 16865887 |
| comparison of virulence between clinical and environmental pseudomonas aeruginosa isolates. | new strains of pseudomonas aeruginosa were isolated from clinical and environmental settings in order to characterize the virulence properties of this opportunistic pathogen. p. aeruginosa was frequently recovered from oil-contaminated samples but not from non-oil-contaminated soils. the virulence of five environmental and five clinical strains of p. aeruginosa was tested using two different models, drosophila melanogaster and lactuca sativa var. capitata l. there was no difference in the virule ... | 2006 | 17236157 |
| detection and quantification by real-time rt-pcr of hepatitis a virus from inoculated tap waters, salad vegetables, and soft fruits: characterization of the method performances. | water, salad vegetables and fruits exposed to fecal contamination may cause outbreaks of hepatitis a. a protocol of viral concentration by filtration on electronegative membrane filter and a protocol based on a viral elution in tris-glycine buffer, ph 9.5 with concentration by polyethylene glycol precipitation were associated with real-time, reverse transcriptase-pcr to detect hepatitis a virus (hav) artificially inoculated in 2 l of tap water, or on 25 g of fruits or salad vegetables. these met ... | 2007 | 17490771 |
| disinfection of iceberg lettuce by titanium dioxide-uv photocatalytic reaction. | securing the physical quality and microbial safety of fresh foods has been a major focus in the food industry. to improve quality and increase the shelf life of fresh produce, disinfection methods have been developed. titanium dioxide (tio2) photocatalytic reactions under uv radiation produce hydroxyl radicals that can be used for disinfection of foodborne pathogenic bacteria. we investigated the effects of tio2-uv photocatalytic disinfection on the shelf life of iceberg lettuce. counts of natur ... | 2009 | 19777894 |
| effects of x-ray radiation on escherichia coli o157:h7, listeria monocytogenes, salmonella enterica and shigella flexneri inoculated on shredded iceberg lettuce. | the main goal of this investigation was to study the efficacy of x-ray doses (0.1, 0.2, 0.3, 0.5, 0.75, 1.0, 1.5 and 2.0 kgy) on inoculated escherichia coli o157: h7, listeria monocytogenes, salmonella enterica and shigella flexneri on shredded iceberg lettuce. the second goal was to study the effect of x-ray on the inherent microflora counts and visual color of shredded iceberg lettuce during storage at 4 degrees c for 30 days. treatment with 1.0 kgy x-ray significantly reduced the population o ... | 2010 | 19913700 |
| modeling logistic performance in quantitative microbial risk assessment. | in quantitative microbial risk assessment (qmra), food safety in the food chain is modeled and simulated. in general, prevalences, concentrations, and numbers of microorganisms in media are investigated in the different steps from farm to fork. the underlying rates and conditions (such as storage times, temperatures, gas conditions, and their distributions) are determined. however, the logistic chain with its queues (storages, shelves) and mechanisms for ordering products is usually not taken in ... | 2010 | 20055976 |
| alternative disinfection techniques to extend the shelf life of minimally processed iceberg lettuce. | chlorination continues to be widely used by the fresh-cut industry for washing and disinfecting minimally processed fruits and vegetables. however, as chlorination has been reported to produce unhealthy by-products such as, chloramines and trihalomethanes, many alternative methods have been reported in the literature. this study examined the use of silver and hydrogen peroxide as possible alternative to chlorination. the results revealed an obvious bactericidal effect of hydrogen peroxide, silve ... | 2010 | 20141938 |
| inactivation of escherichia coli o157:h7 on lettuce, using low-energy x-ray irradiation. | low-energy x-ray irradiation was assessed as a means of eliminating escherichia coli o157:h7 on lettuce. round-cut iceberg lettuce samples (2.54-cm diameter) were dip or spot inoculated with a three-strain cocktail of e. coli o157:h7, stored for 24 h at 4 degrees c, and then irradiated at four dose levels up to 0.25 kgy using a prototype low-energy (70 kv) x-ray irradiator. e. coli o157:h7 survivors were quantified by plating on sorbitol macconkey agar containing cefixime and tellurite. dip inoc ... | 2010 | 20202343 |
| differences in attachment of salmonella enterica serovars to cabbage and lettuce leaves. | this study investigated the ability of five salmonella enterica serovars to attach to and colonize intact and cut lettuce (iceberg, romaine) and cabbage surfaces. biofilm formation and attachment of salmonella serovars to intact and cut leaves were determined. populations of loosely and strongly attached salmonella were obtained to calculate the attachment strength (s(r)). biofilm formation, as determined by microtiter plate assay, varied with strain and growth medium used. salmonella tennessee ... | 2010 | 20226552 |
| development of a cost-effective method for nitrate and nitrite determination in leafy plants and nitrate and nitrite contents of some green leafy vegetables grown in the aegean region of turkey. | an accurate, fast, easily applicable, and cost-effective method for the determination of nitrate and nitrite was developed. this method was much more reliable than the cadmium column reduction method, which is a tedious and time-consuming procedure and not easily applicable. the principle of the method was reduction of nitrate to nitrite with cadmium acetate solution and zinc powder and then treatment with griess reagent. recovery of the method changed from 92.9 to 102.8%, and detection limit wa ... | 2010 | 20384339 |
| multistate outbreak of escherichia coli o157:h7 infections associated with a national fast-food chain, 2006: a study incorporating epidemiological and food source traceback results. | a multistate outbreak of escherichia coli o157:h7 infections occurred in the usa in november-december 2006 in patrons of restaurant chain a. we identified 77 cases with chain a exposure in four states - delaware, new jersey, new york, and pennsylvania. fifty-one (66%) patients were hospitalized, and seven (9%) developed haemolytic uraemic syndrome; none died. in a matched analysis controlling for age in 31 cases and 55 controls, illness was associated with consumption of shredded iceberg lettuce ... | 2011 | 20429971 |
| safety evaluation of an açai-fortified fruit and berry functional juice beverage (monavie active(®)). | the safety of an açai (euterpe oleracea mart.) pulp enriched fruit and berry juice, monavie active®, fortified with the functional ingredient, glucosamine, was studied. the beverage was found not to be mutagenic, clastogenic, cytotoxic, or genotoxic, as determined by the bacterial reverse mutation assay, chromosomal aberration assay, mouse micronucleus assay, and mammalian cell gene mutation (l5178y) assay. the single dose ld50 based on a 14-day acute oral toxicity study is greater than 20,000 m ... | 2010 | 20452390 |
| binding of virus-like particles of norwalk virus to romaine lettuce veins. | noroviruses (nov) annually cause millions of cases of gastrointestinal disease in the united states. nov are associated with raw shellfish outbreaks, particularly oysters, which are thought to bioaccumulate nov particles during the filter-feeding process. nov outbreaks, however, have also been known to occur from other common-source food-borne vehicles, such as lettuce, frozen raspberries, and salad. in this study, we evaluated romaine lettuce as a potential vehicle for nov transmission by testi ... | 2010 | 21037300 |
| efficacy of aerosolized peroxyacetic acid as a sanitizer of lettuce leaves. | aerosolized sanitizer was investigated as a potential alternative to aqueous and gaseous sanitizers for produce. peroxyacetic acid was aerosolized (5.42 to 11.42 microm particle diameter) by a commercially available nebulizer into a model cabinet. iceberg lettuce leaves were inoculated with three strains each of escherichia coli o157:h7, listeria monocytogenes, and salmonella typhimurium and then treated with aerosolized peroxyacetic acid for 10, 30, or 60 min in a model aerosol cabinet at room ... | 2005 | 21132990 |
| occurrence of multidrug resistant extended spectrum beta-lactamase-producing bacteria on iceberg lettuce retailed for human consumption. | antibiotic resistance in bacteria is a global problem exacerbated by the dissemination of resistant bacteria via uncooked food, such as green leafy vegetables. new strains of bacteria are emerging on a daily basis with novel expanded antibiotic resistance profiles. in this pilot study, we examined the occurrence of antibiotic resistant bacteria against five classes of antibiotics on iceberg lettuce retailed in local convenience stores in rochester, michigan. in this study, 138 morphologically di ... | 2015 | 26064922 |
| inactivation of murine norovirus 1, coliphage phix174, and bacillus fragilis phage b40-8 on surfaces and fresh-cut iceberg lettuce by hydrogen peroxide and uv light. | in this study, the inactivating properties of liquid hydrogen peroxide (l-h(2)o(2)), vaporized hydrogen peroxide (v-h(2)o(2)), uv light, and a combination of v-h(2)o(2) and uv light were tested on murine norovirus 1 (mnv-1) and bacteriophages (φx174 and b40-8) as models for human noroviruses. disinfection of surfaces was examined on stainless steel discs based on european standard en 13697 (2001). for fresh-produce decontamination, a mixture of the viruses was inoculated onto shredded iceberg le ... | 2010 | 21183630 |
| effect of curli expression and hydrophobicity of escherichia coli o157:h7 on attachment to fresh produce surfaces. | to investigate the effect of curli expression on cell hydrophobicity, biofilm formation and attachment to cut and intact fresh produce surfaces. | 2011 | 21205101 |
| salmonella typhimurium internalization is variable in leafy vegetables and fresh herbs. | despite washing and decontamination, outbreaks linked to consumption of fresh or minimally-processed leafy greens have been increasingly reported in recent years. in order to assure the safety of produce it is necessary to gain knowledge regarding the exact routes of contamination. leaf internalization through stomata was previously reported as a potential route of contamination, which renders food-borne pathogens protected from washing and disinfection by sanitizers. in the present study we hav ... | 2011 | 21262550 |
| inactivation of a human norovirus surrogate, human norovirus virus-like particles, and vesicular stomatitis virus by gamma irradiation. | gamma irradiation is a nonthermal processing technology that has been used for the preservation of a variety of food products. this technology has been shown to effectively inactivate bacterial pathogens. currently, the fda has approved doses of up to 4.0 kgy to control food-borne pathogens in fresh iceberg lettuce and spinach. however, whether this dose range effectively inactivates food-borne viruses is less understood. we have performed a systematic study on the inactivation of a human norovi ... | 2011 | 21441330 |
| acids in combination with sodium dodecyl sulfate caused quality deterioration of fresh-cut iceberg lettuce during storage in modified atmosphere package. | recent studies showed that sodium acid sulfate (sas) and levulinic acid (la) in combination with sodium dodecyl sulfate (sds) was effective in inactivating human pathogens on romaine lettuce. the present study investigated the effects of la and sas in combination with sds (as compared with citric acid and chlorine) on the inactivation of e. coli o157:h7 and sensory quality of fresh-cut iceberg lettuce in modified atmosphere packages during storage at 4 °c. results showed that la (0.5% to 3%) and ... | 2010 | 21535517 |
| effect of storage temperature and duration on the behavior of escherichia coli o157:h7 on packaged fresh-cut salad containing romaine and iceberg lettuce. | this study investigated the impact of storage temperature and duration on the fate of escherichia coli o157:h7 on commercially packaged lettuce salads, and on product quality. fresh-cut romaine and iceberg lettuce salads of different commercial brands were obtained from both retail and wholesale stores. the packages were cut open at one end, the lettuce salad inoculated with e. coli o157:h7 via a fine mist spray, and resealed with or without an initial n(2) flush to match the original package at ... | 2010 | 21535546 |
| chlorine stabilizer t-128 enhances efficacy of chlorine against cross-contamination by e. coli o157:h7 and salmonella in fresh-cut lettuce processing. | during fresh-cut produce processing, organic materials released from cut tissues can rapidly react with free chlorine in the wash solution, leading to the potential survival of foodborne bacterial pathogens, and cross-contamination when the free chlorine is depleted. a reported chlorine stabilizer, t-128, has been developed to address this problem. in this study, we evaluated the ability of t-128 to stabilize free chlorine in wash solutions in the presence of high organic loads generated by the ... | 2011 | 21535847 |
| effect of modified atmosphere packaging on the persistence and expression of virulence factors of escherichia coli o157:h7 on shredded iceberg lettuce. | fresh-cut leafy greens contaminated with escherichia coli o157:h7 have caused foodborne outbreaks. packaging conditions, coupled with abusive storage temperatures of contaminated lettuce, were evaluated for their effect on the potential virulence of e. coli o157:h7. shredded lettuce was inoculated with 5.58 and 3.98 log cfu e. coli o157:h7 per g and stored at 4 and 15°c, respectively, for up to 10 days. lettuce was packaged under treatment a (modified atmosphere packaging conditions used for com ... | 2011 | 21549041 |
| use of the systems approach to determine the fate of escherichia coli o157:h7 on fresh lettuce and spinach. | lettuce and spinach inoculated with escherichia coli o157:h7 were processed and handled in ways that might occur in commercial situations, including variations in holding times before and after product cooling, transportation conditions and temperatures, wash treatments, and product storage temperatures and times. populations of background microflora and e. coli o157:h7 were enumerated after each step in the system. data analysis was done to predict response variables with a combination of indep ... | 2009 | 19681286 |
| microbial antagonists of escherichia coli o157:h7 on fresh-cut lettuce and spinach. | fresh-cut lettuce and spinach can become contaminated with pathogens at numerous points from the field to the retail market. natural microflora present on fresh produce may help reduce the pathogen load. the objective of this study was to isolate natural microflora from fresh-cut iceberg lettuce and baby spinach and to determine whether these bacteria were antagonistic toward escherichia coli o157:h7. samples were collected under conditions that mimicked actual practices between production and r ... | 2009 | 19681287 |
| role of o-antigen on the escherichia coli o157:h7 cells hydrophobicity, charge and ability to attach to lettuce. | environmental factors encountered during growing and harvesting may contribute to escherichia coli o157:h7 contamination of lettuce. limited nutrients and extended exposure to water may cause e. coli o157:h7 to shed its o antigen. absence of the o157-polysaccharide antigen could affect the cell's physicochemical properties (hydrophobicity and cell charge) and ultimately influence its attachment to surfaces. the objectives of this study were to evaluate the effect of the e. coli o157:h7 o-antigen ... | 2011 | 21550681 |
| reduction of escherichia coli o157:h7 on produce by use of electrolyzed water under simulated food service operation conditions. | treatment of fresh fruits and vegetables with electrolyzed water (ew) has been shown to kill or reduce foodborne pathogens. we evaluated the efficacy of ew in killing escherichia coli o157:h7 on iceberg lettuce, cabbage, lemons, and tomatoes by using washing and/or chilling treatments simulating those followed in some food service kitchens. greatest reduction levels on lettuce were achieved by sequentially washing with 14-a (amperage) acidic ew (acew) for 15 or 30 s followed by chilling in 16-a ... | 2009 | 19777886 |
| iceberg lettuce as suggested source of a nationwide outbreak caused by two salmonella serotypes, newport and reading, in finland in 2008. | a nationwide outbreak of salmonella enterica serotypes newport and reading occurred between 17 october and 28 november 2008 in finland. a total of 77 culture-confirmed salmonella newport and 30 salmonella reading cases, including one case with a double infection, were reported. all strains isolated from the patients were subtyped using serotyping, microbial resistance profiling, and pulsed-field gel electrophoresis (pfge). here, the pfge patterns of the studied salmonella newport strains were id ... | 2011 | 21669088 |
| multiple outbreaks of salmonella braenderup associated with consumption of iceberg lettuce. | the aim of this study was to describe the findings from an outbreak investigation following several apparently unrelated community outbreaks of gastroenteritis. epidemiological, environmental, laboratory and traceback investigations were used to identify the source of the outbreak. we enrolled 23 (of 29) laboratory confirmed cases and 24 neighbourhood case-nominated controls in a case-control study which revealed that illness was associated with consumption of iceberg lettuce (matched odds ratio ... | 2011 | 21916661 |
| quantitative microbial risk assessment for escherichia coli o157 on lettuce, based on survival data from controlled studies in a climate chamber. | the aims of the study were to determine the survival of escherichia coli o157 on lettuce as a function of temperature and light intensity, and to use that information in a screening-level quantitative microbial risk assessment (qmra) in order to evaluate risk-reducing strategies including irrigation water quality guidelines, rinsing, and holding time between last irrigation and harvest. iceberg lettuce was grown in a climate chamber and inoculated with e. coli o157. bacterial numbers were deter ... | 2011 | 22186038 |
| a survey of iceberg lettuce for the presence of salmonella, escherichia coli o157:h7, and listeria monocytogenes in japan. | no information has been available on the prevalence of pathogens in fresh produce in japan. in the present study, information was collected on the occurrence of contamination by salmonella, escherichia coli o157:h7, and listeria monocytogenes in iceberg lettuce in a japanese retail store. a total of 419 samples of lettuce that had been harvested in different districts and/or by different producers from july 2008 to march 2009 were examined. a multiplex pcr method was used to simultaneously ident ... | 2011 | 21902925 |
| sensitivity of poliovirus type 1 chat strain and rotavirus sa-11 to e-beam irradiation on iceberg lettuce and spinach: quantifying the reduction in potential health risks. | fresh produce such as lettuce and spinach serve as routes of foodborne illnesses. the u.s. fda has approved the use of ionizing irradiation upto 4 kgy as a pathogen kill step for fresh cut lettuce and spinach. the focus of this study was to determine the inactivation of poliovirus and rotavirus on lettuce and spinach when exposed to varying doses of high energy e-beam irradiation and to calculate the theoretical reduction in infection risks that can be achieved under different contamination scen ... | 2011 | 22179244 |
| Effect of wash treatments on reducing human norovirus on iceberg lettuce and perilla leaf. | Human noroviruses (NoVs) are major causes of nonbacterial gastroenteritis; they are transmitted by food and water, as well as person-to-person. The consumption of contaminated raw or uncooked food such as vegetables and fruits has been identified as a common source of human NoV outbreaks. In an effort to understand the survival and persistence of human NoVs on fresh produce, the efficacy of washing treatments in the removal of human NoVs from vegetables was evaluated. This study used artificial ... | 2011 | 22054192 |
| assessment of escherichia coli o157:h7 transference from soil to iceberg lettuce via a contaminated field coring harvesting knife. | the potential for lettuce field-coring harvesting knives to cross-contaminate lettuce heads with pathogens was evaluated. rings and blades of the harvest knives artificially contaminated with escherichia coli o157:h7 (ehec), were used to core three successive heads of iceberg lettuce. the coring rings and blades were inoculated by dipping into soils containing ehec at concentration ranges of 1-10(5) mpn/g soil. factors that influenced ehec transference from soil to iceberg lettuce via contaminat ... | 2011 | 22189025 |
| antimicrobial activity of apple, hibiscus, olive, and hydrogen peroxide formulations against salmonella enterica on organic leafy greens. | salmonella enterica is one of the most common bacterial pathogens implicated in foodborne outbreaks involving fresh produce in the last decade. in an effort to discover natural antimicrobials for use on fresh produce, the objective of the present study was to evaluate the effectiveness of different antimicrobial plant extract-concentrate formulations on four types of organic leafy greens inoculated with s. enterica serovar newport. the leafy greens tested included organic romaine and iceberg le ... | 2011 | 22004815 |
| survival and growth of foodborne pathogens in minimally processed vegetables at 4 and 15 °c. | we conducted this study to investigate the survival and growth of pathogens on fresh vegetables stored at 4 and 15 °c. vegetables (romaine lettuce, iceberg lettuce, perilla leaves, and sprouts) were inoculated with 4 pathogens (salmonella enterica serovar typhimurium, staphylococcus aureus, listeria monocytogenes, and escherichia coli o157:h7) and stored at 2 different temperatures for different periods of time (3, 6, 9, 12, and 15 d at 4 °c and 1, 2, 3, 5, and 7 d at 15 °c). populations of the ... | 2012 | 22260117 |
| antimicrobial activity of oregano oil against antibiotic-resistant salmonella enterica on organic leafy greens at varying exposure times and storage temperatures. | the objective of this study was to evaluate the effectiveness of oregano oil on four organic leafy greens (iceberg and romaine lettuces and mature and baby spinaches) inoculated with salmonella newport as a function of treatment exposure times as well as storage temperatures. leaf samples were washed, dip inoculated with s. newport (6-log cfu/ml) and dried. oregano oil was prepared at 0.1, 0.3, and 0.5% concentrations in sterile phosphate buffered saline (pbs). inoculated leaves were immersed in ... | 2012 | 23498188 |
| comparison of sample preparation methods for the recovery of foodborne pathogens from fresh produce. | sample preparation methods (pummeling, pulsifying, sonication, and shaking by hand) were compared for achieving maximum recovery of foodborne pathogens from iceberg lettuce, perilla leaves, cucumber, green pepper, and cherry tomato. antimicrobial and dehydration effects also were examined to investigate causes of poor recovery of pathogens. each produce type was inoculated with escherichia coli o157:h7, salmonella typhimurium, listeria monocytogenes, staphylococcus aureus, and bacillus cereus at ... | 2012 | 22980003 |
| prevalence and characterization of esbl- and ampc-producing enterobacteriaceae on retail vegetables. | in total 1216 vegetables obtained from dutch stores during 2012 and 2013 were analysed to determine the prevalence of 3rd-generation cephalosporin (3gc) resistant bacteria on soil-grown fresh produce possibly consumed raw. vegetables grown conventionally and organically, from dutch as well as foreign origin were compared. included were the following vegetable types; blanched celery (n=192), bunched carrots (n=190), butterhead lettuce (n=137), chicory (n=96), endive (n=188), iceberg lettuce (n=19 ... | 2015 | 25828704 |
| extended spectrum ß-lactamase- and constitutively ampc-producing enterobacteriaceae on fresh produce and in the agricultural environment. | the attribution of fresh produce to the overall community-associated exposure of humans to esbl- or ampc-producing bacteria is currently unknown. to address this issue, the prevalence of esbl- and ampc-producing enterobacteriaceae on fresh produce produced in the netherlands was determined. seven vegetable types that are consumed raw were selected: blanched celery, bunched carrots, chicory, endive, iceberg lettuce, mushrooms, and radish. the vegetables were mostly obtained from supermarkets. to ... | 2014 | 24211774 |
| clostridium difficile with moxifloxacin/clindamycin resistance in vegetables in ohio, usa, and prevalence meta-analysis. | we (i) determined the prevalence of clostridium difficile and their antimicrobial resistance to six antimicrobial classes, in a variety of fresh vegetables sold in retail in ohio, usa, and (ii) conducted cumulative meta-analysis of reported prevalence in vegetables since the 1990s. six antimicrobial classes were tested for their relevance as risk factors for c. difficile infections (cdis) (clindamycin, moxifloxacin) or their clinical priority as exhaustive therapeutic options (metronidazole, van ... | 2014 | 25580297 |