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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 ...200616503303
bacterial contamination of vegetables served in hospitals.to study bacterial contamination of fresh vegetables before cleaning and before serving to patients in 14 hospitals.200516850639
relative efficacy of sodium hypochlorite wash versus irradiation to inactivate escherichia coli o157:h7 internalized in leaves of romaine lettuce and baby spinach.pathogenic bacteria that become internalized in leaf tissues are protected from the antimicrobial effects of surface treatments. ionizing radiation is known to penetrate food tissues, but the efficacy of the process against internalized bacteria is unknown. leaves of romaine lettuce and baby spinach were cut into pieces, submerged in a cocktail mixture of three isolates of escherichia coli o157:h7, and subjected to a vacuum perfusion process to force the bacterial cells into the intercellular sp ...200718044430
assessment of contamination potential of lettuce by salmonella enterica serovar newport added to the plant growing medium.the capacity of salmonella enterica serovar newport to contaminate romaine lettuce (lactuca sativa l. cv. nogal) via the root system was evaluated in 17-, 20-, and 33-day-old plants. apparent internalization of salmonella via the root to the above-ground parts was identified in 33- but not 17- or 20-day-old plants and was stimulated by root decapitation. leaves of lettuce plants with intact and damaged roots harbored salmonella at 500 +/- 120 and 5,130 +/- 440 cfu/g of leaf, respectively, at 2 d ...200717685348
rapid detection of escherichia coli o157:h7 inoculated in ground beef, chicken carcass, and lettuce samples with an immunomagnetic chemiluminescence fiber-optic biosensor.a biosensor was evaluated with regard to its usefulness in the rapid detection of escherichia coli o157:h7 inoculated in ground beef, chicken carcass, and romaine lettuce samples. the biosensor consisted of a chemiluminescence reaction cell, a fiber-optic light guide, and a luminometer linked to a personal computer in conjunction with immunomagnetic separation. the samples inoculated with e. coli o157:h7 were first centrifuged and suspended in buffered peptone water and then incubated with anti- ...200312636312
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 ...200415222557
electron beam and gamma irradiation effectively reduce listeria monocytogenes populations on chopped romaine lettuce.fresh, chopped romaine lettuce contaminated with a seven-strain cocktail of listeria monocytogenes (in a solution containing approximately 10(8) organisms per ml) that had attained a level of contamination of between 7 and 8 log cfu/g was packaged in 15-g samples. the lettuce was irradiated with a co60 source at 1.15 or 0.51 kgy and then stored at 4 degrees c. in addition, samples contaminated with isolated strains 16397, 0733, and 1992 were subjected to either electron beam irradiation at doses ...200616541687
leaf age as a risk factor in contamination of lettuce with escherichia coli o157:h7 and salmonella enterica.outbreaks of escherichia coli o157:h7 infections have been linked increasingly to leafy greens, particularly to lettuce. we present here the first evidence that this enteric pathogen can multiply on the leaves of romaine lettuce plants. the increases in population size of e. coli o157:h7 in the phyllosphere of young lettuce plants ranged from 16- to 100-fold under conditions of warm temperature and the presence of free water on the leaves and varied significantly with leaf age. the population si ...200818310433
the influence of different food sources on cercarial production in lymnaea truncatula experimentally infected with digenea.experimental infections of lymnaea truncatula with a digenean species (fasciola gigantica, f. hepatica, or paramphistomum daubneyi) were performed under laboratory conditions to study the effect of four sources of food (microalgae, romaine lettuce, wheat germs, or modified boray diet) on cercarial production. the mean number of f. hepatica, f. gigantica, or p. daubneyi cercariae was significantly greater when snail food was microalgae or boray diet. the lowest cost prices for 100 metacercariae o ...200211873822
the use of tetraphyll as food for snails increases the intensity of cercarial shedding in galba truncatula infected with fasciola hepatica.experimental infections of galba truncatula with fasciola hepatica were carried out under laboratory conditions to determine why the use of tetraphyll, when provided every 3 days as food for snails, stimulated the intensity of cercarial shedding. in snails raised on cos lettuce and tetraphyll, the number of metacercariae was significantly higher than that recorded in controls on lettuce only. in the former group, numerous metacercariae were counted on day 1 of every 3-day period (when snails fed ...200415290250
the experimental production of fasciola hepatica metacercariae from three aquatic populations of galba truncatula.laboratory investigations on three aquatic populations of galba truncatula, originating from the peruvian altiplano and french massif central, were carried out during three successive snail generations to determine if these populations might be successfully used for the metacercarial production of fasciola hepatica under experimental conditions. high numbers of surviving snails at day 30 post-exposure (>70%), high prevalences of f. hepatica infections (>60%), and prolonged productions of cercari ...200312895288
antioxidant capacity of lettuce leaf tissue increases after wounding.wounding induced the accumulation of phenolic compounds in iceberg and romaine lettuce leaf tissue. phenolic concentrations were quantified after holding the leaf tissue at 10 degrees c for 48 h as the absorbance of a methanol extract at 320 nm, and by the folin-ciocalteu method. heat-shock treatments applied by immersing tissue in 45 degrees c water for 2.5 min before or after wounding reduced the accumulation of phenolic compounds. compared to the nonwounded, nonheat-shocked controls, these an ...200212475267
effects of diet on the development of schistosoma mansoni in biomphalaria glabrata and on the neutral lipid content of the digestive gland-gonad complex of the snail.in a previous study, when the snail biomphalaria glabrata was infected with schistosoma mansoni and maintained on a diet of hen's egg yolk, it produced fully developed cercariae in about one-half the time taken by snails fed romaine lettuce. increased lipids were also noted in the snails fed the yolk diet. the purpose of the present study was to further investigate nutritional effects of a high-lipid diet on larval schistosome development and to reexamine the time to cercarial patency in infecte ...200111227897
linear dichroism of microalgae, developing thylakoids and isolated pigment-protein complexes in stretched poly(vinyl alcohol) films at 77 k.a variety of unicellular algae, thylakoids from higher plants in different stages of maturity and isolated pigment-protein complexes were oriented in stretched polyvinyl alcohol films. low temperature linear dichroism (ld) spectra of chlorella pyrenoidosa and higher plant thylakoids in the films were very similar to those obtained after orientation of similar samples using magnetic or electric fields. positive ld bands corresponding to chl a (670) and (682) and negative bands due to chl a (658) ...19806774749
transfer of salmonella and campylobacter from stainless steel to romaine lettuce.the degree of transfer of campylobacter jejuni and salmonella enterica serovar typhimurium was evaluated from a stainless steel contact surface to a ready-to-eat food (lettuce). stainless steel coupons (25 cm2) were inoculated with a 20-microl drop of either c. jejuni or salmonella typhimurium to provide an inoculum level of approximately 10(6) cfu/28 mm2. wet and dry lettuce (lactuca sativa var. longifolia) pieces (9 cm2) were placed onto the inoculated stainless steel surface for 10 s after th ...200314672218
comparison of phylloquinone bioavailability from food sources or a supplement in human subjects.phylloquinone (k) absorption was assessed in 22- to 30-y-old human subjects consuming a standard test meal [402 kcal (1682 kj), 27% energy from fat]. the absorption of phylloquinone, measured over a 9-h period as the area under the curve (auc), was higher (p < 0.01) after the consumption of a 500- microgram phylloquinone tablet [27.55 +/- 10.08 nmol/(l. h), n = 8] than after the ingestion of 495 microgram phylloquinone as 150 g of raw spinach [4.79 +/- 1.11 nmol/(l. h), n = 3]. less phylloquinon ...199910356087
analysis of native microflora and selection of strains antagonistic to human pathogens on fresh produce.the native microflora of three types of produce (green bell peppers, romaine lettuce, and prepeeled baby carrots) and two types of sprouting seeds (alfalfa and clover) were investigated. aerobic plate count (apc) for each produce or seed type as determined on pseudomonas agar f (paf) with incubation at 28 degrees c was in the range of 4 to 7 log cfu per g of tissue or seed. there was no significant difference (p > or = 0.05) in apc when the determinations were made with three agar media includin ...200111510644
folic acid compounds in romaine lettuce.the composition of folate coenzymes in romaine lettuce was studied. lettuce extract was purified on qae-sephadex a-25 and folate compounds were separated into a monoglutamate fraction and a polyglutamate fraction by chromatography on sephadex g-15. both the mono- and poly-glutamate fractions were resolved on deae-cellulose. positive identification of deae peaks was made by further cochromatography with high specific activity radioactive marker folate compounds and with differential microbiologic ...1977407992
transfer of escherichia coli o157:h7 to romaine lettuce due to contact water from melting ice.ice can be used to chill romaine lettuce and maintain relative humidity during transportation. escherichia coli o157:h7 may contaminate water used for ice. the objective of this study was to determine the potential for e. coli o157:h7 contamination of romaine lettuce from either ice contaminated with the pathogen or by transfer from lettuce surfaces via melting ice. in experiment 1, lettuce was spot inoculated with e. coli o157:h7 and chilled with ice prepared from uncontaminated tap water. in e ...200818326172
escherichia coli o157:h7 stress and virulence gene expression on romaine lettuce using comparative real-time pcr.foodborne outbreaks attributed to the contamination of fresh produce with escherichia coli o157:h7 are a growing concern. in particular, leafy-green vegetables, including lettuce and spinach, are susceptible to contamination by irrigation water, manure, and food processing and storage practices. the survival of e. coli o157:h7 and natural microflora on romaine lettuce stored at 4 degrees c and 15 degrees c over a 9-day period was evaluated by plate counts. a two-step reverse-transcription compar ...200919248811
interactions of salmonella enterica with lettuce leaves.to investigate the interactions of salmonella enterica with abiotic and plant surfaces and their effect on the tolerance of the pathogen to various stressors.200919239550
molecular cloning of violaxanthin de-epoxidase from romaine lettuce and expression in escherichia coli.plants need to avoid or dissipate excess light energy to protect photosystem ii (psii) from photoinhibitory damage. higher plants have a conserved system that dissipates excess energy as heat in the light-harvesting complexes of psii that depends on the transthylakoid delta ph and violaxanthin de-epoxidase (vde) activity. to our knowledge, we report the first cloning of a cdna encoding vde and expression of functional enzyme in escherichia coli. vde is nuclear encoded and has a transit peptide w ...19968692813
contents of phytosterols in vegetables and fruits commonly consumed in china.to quantify five specific dietary phytosterols and phytostanols in vegetables and fruits commonly consumed in china.200819263798
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 ...200616387377
fasciola hepatica: the effect of food quality on the development of redial generations in galba truncatula infected with allopatric miracidia.individual bimiracidial infections of french galba truncatula with an allopatric (moroccan) isolate of fasciola hepatica were carried out under laboratory conditions to count free rediae and intraredial daughter rediae in snails just after their death, and to determine whether feeding the snails on lettuce only or lettuce plus tetraphyll had an effect on the development of redial generations. controls consisted of snails infected with sympatric (french) miracidia and reared with lettuce only. in ...200414586643
prevalence of salmonella in vegetables from mexico.the present study is an overview of the role of vegetables as a transmission vehicle of salmonella in mexico. one hundred samples of each of 17 different vegetables were analyzed during a period of 18 months. salmonella was isolated from 98 samples. salmonella enterica serovar typhimurium was isolated from the highest percentage of samples with typeable salmonella isolates (23.9%), followed by s. enterica subsp. arizonae and salmonella choleraesuis each from 16.9%, salmonella gallinarum from 11. ...200919610340
fasciola hepatica: cercarial productivity of redial generations in long-surviving galba truncatula.bimiracidial infections of galba truncatula with fasciola hepatica were carried out to determine the effect of food quality on the frequency of 1- and 2-sporocyst infections, to analyse its impact on the developmental patterns (normal, or abnormal) of redial generations, and to verify its consequences on cercarial production. these investigations were performed in snails reared at 20 degrees c and provided with cos lettuce and commercial fish food (tetraphyll) as a food source until their death. ...200415153282
hepatopulmonary masses after eating romaine lettuce. 200314723385
hypochlorite treatments are not a significant source of perchlorate exposure in lettuce.leafy vegetables, such as lettuce ( lactuca sativa l), have been identified as a potential source of perchlorate exposure to humans. perchlorate is of concern because excessive amounts may impair thyroid function by inhibiting iodide uptake by the sodium iodide symporter. perchlorate has been identified as an oxidation product in sodium hypochlorite. dilute hypochlorite solutions are widely used on lettuce as a preservative and as a treatment to reduce microbial food risks. however, the potentia ...200919245207
leafy vegetable mix supplementation improves lipid profiles and antioxidant status in c57bl/6j mice fed a high fat and high cholesterol diet.daily consumption of an antioxidant-rich leafy vegetable mix (lvm) was assessed for beneficial effects on plasma lipid profiles, tissue lipid peroxidation, and oxidative dna damage in c57bl/6j mice fed a high fat and high cholesterol diet (20% fat and 1% cholesterol, wt/wt) for 4 weeks. the lvm contained beet leaf, angelica, red leaf lettuce, dandelion, green cos lettuce, lollo rosso, romaine lettuce (12.5%, respectively), scotch kale, and red kale (6.25%, respectively). the mice (n = 16) were r ...200919735190
heat and drought stress during growth of lettuce (lactuca sativa l.) does not promote internalization of escherichia coli o157:h7.studies were done to determine the effect of heat stress on internalization of escherichia coli o157:h7 in lettuce subjected to different watering practices during growth. iceberg and romaine lettuce were grown in sandy soil in an environmental chamber at 23 degrees c during the day and 7 degrees c at night, with a 12-h photoperiod. thirty days after transplanting seedlings, potting soil was inoculated with a five-strain mixture of green fluorescent protein-labeled e. coli o157:h7 at populations ...200920003727
variability in the prevalence of infection and cercarial production in galba truncatula raised on a high-quality diet.two experiments using seven populations of galba truncatula were carried out to analyse the effect of food quality (cos lettuce only, or cos lettuce+tetraphyll) on the characteristics of infections: (1) in a single population of g. truncatula infected by one of three digenea (first experiment), and (2) in seven populations of g. truncatula differing in their susceptibility to fasciola hepatica miracidia (second experiment). in most groups, food quality did not have a significant effect on the su ...200414714176
manure- and biosolids-resident murine norovirus 1 attachment to and internalization by romaine lettuce.the attachment of murine norovirus 1 (mnv) in biosolids, swine manure, and dairy manure to romaine lettuce and internalization of this virus were evaluated. the mnv in animal manures had behavior similar to that of pure mnv; however, mnv in biosolids had significantly higher levels of attachment and internalization than pure mnv or mnv in manures. the incubation time did not affect the attachment of mnv in biosolids or manure. confocal microscopy was used to observe mnv on lettuce after sybr gol ...201019933344
antineurodegenerative effect of phenolic extracts and caffeic acid derivatives in romaine lettuce on neuron-like pc-12 cells.in recent decades, romaine lettuce has been one of the fastest growing vegetables with respect to its consumption and production. an understanding is needed of the effect of major phenolic phytochemicals from romaine lettuce on biological protection for neuron-like pc-12 cells. phenolics in fresh romaine lettuce were extracted, and then its total phenolics and total antioxidant capacity were measured spectrophotometrically. neuroprotective effects of phenolic extract of romaine lettuce and its p ...201020553182
transcriptome analysis of escherichia coli o157:h7 exposed to lysates of lettuce leaves.harvesting and processing of leafy greens inherently cause plant tissue damage, creating niches on leaves that human pathogens can exploit. we previously demonstrated that escherichia coli o157:h7 (eco157) multiplies more rapidly on shredded leaves than on intact leaves (m. t. brandl, appl. environ. microbiol. 74:5285-5289, 2008). to investigate how eco157 cells adapt to physicochemical conditions in injured lettuce tissue, we used microarray-based whole-genome transcriptional profiling to chara ...201020061451
behavior of escherichia coli o157:h7 on damaged leaves of spinach, lettuce, cilantro, and parsley stored at abusive temperatures.recent foodborne illness outbreaks associated with the consumption of leafy green produce indicates a need for additional information on the behavior of pathogenic bacteria on these products. previous research indicates that pathogen growth and survival is enhanced by leaf damage. the objective of this study was to compare the behavior of escherichia coli o157:h7 on damaged leaves of baby romaine lettuce, spinach, cilantro, and parsley stored at three abusive temperatures (8, 12, and 15 degrees ...201020132665
one ring or two? determination of ring number in carotenoids by lycopene epsilon-cyclases.carotenoids in the photosynthetic membranes of plants typically contain two beta-rings (e.g., beta-carotene and zeaxanthin) or one epsilon- and one beta-ring (e.g., lutein). carotenoids with two epsilon-rings are uncommon. we reported earlier that the arabidopsis thaliana lycopene epsilon-cyclase (lcye) adds one epsilon-ring to the symmetrical linear substrate lycopene, whereas the structurally related lycopene beta-cyclase (lcyb) adds two beta-rings. here we describe a cdna encoding lcye in rom ...200111226339
presence and potential for horizontal transfer of antibiotic resistance in oxidase-positive bacteria populating raw salad vegetables.to assess whether domestically grown fresh salad vegetables constitute a possible reservoir of antibiotic resistance for canadian consumers, aerobic bacteria capable of forming colonies at 30 degrees c on nutrient-limited media were recovered from a single sampling of romaine lettuce, savoy spinach and alfalfa sprouts, then examined for their susceptibility to ten antibiotics and the carriage of potentially mobile r-plasmids and integrons. of the 140 isolates resistant to one or more antibiotic, ...200818632174
whole-leaf wash improves chlorine efficacy for microbial reduction and prevents pathogen cross-contamination during fresh-cut lettuce processing.currently, most fresh-cut processing facilities in the united states use chlorinated water or other sanitizer solutions for microbial reduction after lettuce is cut. freshly cut lettuce releases significant amounts of organic matter that negatively impacts the effectiveness of chlorine or other sanitizers for microbial reduction. the objective of this study is to evaluate whether a sanitizer wash before cutting improves microbial reduction efficacy compared to a traditional postcutting sanitizer ...201020629885
plant lesions promote the rapid multiplication of escherichia coli o157:h7 on postharvest lettuce.several outbreaks of escherichia coli o157:h7 infections have been associated with minimally processed leafy vegetables in the united states. harvesting and processing cause plant tissue damage. in order to assess the role of plant tissue damage in the contamination of leafy greens with e. coli o157:h7, the effect of mechanical, physiological, and plant disease-induced lesions on the growth of this pathogen on postharvest romaine lettuce was investigated. within only 4 h after inoculation, the p ...200818641153
reduction of escherichia coli o157:h7 viability on leafy green vegetables by treatment with a bacteriophage mixture and trans-cinnamaldehyde.enterohemorrhagic escherichia coli (ehec) o157:h7 has been recognized as a major foodborne pathogen responsible for frequent gastroenteritis outbreaks. phages and essential oils can be used as a natural antimicrobial method to reduce bacterial pathogens from the food supply. the objective of this study was to determine the effect of a bacteriophage cocktail, bec8, alone and in combination with the essential oil trans-cinnameldehyde (tc) on the viability of a mixture of ehec o157:h7 strains appli ...201021056787
efficacy of adding detergents to sanitizer solutions for inactivation of escherichia coli o157:h7 on romaine lettuce.numerous escherichia coli o157:h7 outbreaks have been linked to consumption of fresh lettuce. the development of effective and easily implemented wash treatment could reduce such incidents. the purpose of this study was to evaluate the addition of food-grade detergents to sanitizer solutions for inactivation of e. coli o157:h7 on romaine lettuce. freshly-cut leaves of romaine lettuce were dip-inoculated to achieve a final cell concentration of 7.8±0.2 log cfu/g, air-dried for 2h, and stored over ...201121529976
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 ...201021535517
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 ...201021037300
internalization of murine norovirus 1 by lactuca sativa during irrigation.romaine lettuce (lactuca sativa) was grown hydroponically or in soil and challenged with murine norovirus 1 (mnv) under two conditions: one mimicking a severe one-time contamination event and another mimicking a lower level of contamination occurring over time. in each condition, lettuce was challenged with mnv delivered at the roots. in the first case, contamination occurred on day one with 5 × 10(8) reverse transcriptase quantitative pcr (rt-qpcr) u/ml mnv in nutrient buffer, and irrigation wa ...201121296944
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.201121205101
surrogate selection for escherichia coli o157:h7 based on cryotolerance and attachment to romaine lettuce.using nonpathogenic surrogates in place of pathogens when evaluating commercial food processing operations offers safety advantages, but their usefulness may be limited if they do not behave in the same manner in challenge situations. nonpathogenic escherichia coli strains were compared with e. coli o157:h7 based on cryotolerance, cell surface characteristics (hydrophobicity, zeta potential, and morphology), and attachment to lettuce. populations for all strains were reduced less than 1 log cfu/ ...200919681259
impact of preinoculation culture conditions on the behavior of escherichia coli o157:h7 inoculated onto romaine lettuce (lactuca sativa) plants and cut leaf surfaces.inoculum preparation methods can impact growth or survival of organisms inoculated into foods, thus complicating direct comparison of results among studies. the objective of this study was to evaluate preinoculation culture preparation for impact on escherichia coli o157:h7 inoculated onto leaves of romaine lettuce plants and cut leaf surfaces. e. coli o157:h7 was grown quiescently or shaken at 15, 25, or 37 degrees c to different growth phases in tryptic soy or m9 minimal salts broth or agar. c ...200919681285
binding of human gii.4 norovirus virus-like particles to carbohydrates of romaine lettuce leaf cell wall materials.norovirus (nov) genogroup ii genotype 4 (gii.4) strains are the dominant cause of the majority of food-borne outbreaks, including those that involve leafy greens, such as lettuce. since human novs use carbohydrates of histo-blood group antigens as receptors/coreceptors, we examined the role of carbohydrates in the attachment of nov to lettuce leaves by using virus-like particles (vlps) of a human nov/gii.4 strain. immunofluorescence analysis showed that the vlps attached to the leaf surface, esp ...201122138991
distribution of salmonella typhimurium in romaine lettuce leaves.leafy greens are occasionally involved in outbreaks of enteric pathogens. in order to control the plant contamination it is necessary to understand the factors that influence enteric pathogen-plant interactions. attachment of salmonella enterica serovar typhimurium to lettuce leaves has been demonstrated before; however, only limited information is available regarding the localization and distribution of immigrant salmonella on the leaf surface. to extend our knowledge regarding initial pathogen ...201121569943
slicing under chlorinated water improves the disinfection of fresh-cut romaine lettuce.the aim of this study was to determine whether the timing or mode of application influences the antimicrobial efficacy of a sodium hypochlorite solution against microorganisms on fresh-cut romaine lettuce. lettuce leaves were treated with a solution of sodium hypochlorite containing 70 mg liter(-1) free chlorine prior to slicing (wls), while submerged in the solution (cws), or after slicing (pcs), the last being common practice in the fresh-cut industry. immediate antimicrobial effects were det ...201122186056
escherichia coli o157:h7 biofilm formation on romaine lettuce and spinach leaf surfaces reduces efficacy of irradiation and sodium hypochlorite washes.escherichia coli o157:h7 contamination of leafy green vegetables is an ongoing concern for consumers. biofilm-associated pathogens are relatively resistant to chemical treatments, but little is known about their response to irradiation. leaves of romaine lettuce and baby spinach were dip inoculated with e. coli o157:h7 and stored at 4 degrees c for various times (0, 24, 48, 72 h) to allow biofilms to form. after each time, leaves were treated with either a 3-min wash with a sodium hypochlorite s ...201020629883
outbreaks of cyclosporiasis--united states, june-august 2013.during june-august 2013, cdc, state and local public health officials, and the food and drug administration (fda) investigated an unusually large number of reports of cyclosporiasis (compared with annual reports to the national notifiable disease surveillance system [e.g., 123 cases in 2012]), an intestinal infection caused by the parasite cyclospora cayetanensis. by september 20, cdc had been notified of 643 cases from 25 states, primarily texas (278 cases), iowa (153), and nebraska (86). inves ...201324172881
persistence of escherichia coli on injured vegetable plants.minor shoot injury to glasshouse celery, cos lettuce and chive plants significantly increased the persistence of applied escherichia coli (p<0.05). after 1 week, mean counts of about 5 log(10) cfu/g decreased to fewer than 0.5 log(10) cfu/g on the uninjured plants, compared to 4 log(10) cfu/g or more on injured plants. by the end of the 3-week long experiments, counts from the uninjured plants were 0.21 log(10) cfu/g or fewer, but 2.8, 2.3 and 5.1 log(10) cfu/g on injured cos lettuce, celery and ...201020156661
bacteriological quality of vegetables from organic and conventional production in different areas of korea.foods grown in organic production systems have been described as representing an increased risk to public health compared with foods from conventional production. leafy vegetables (spinach, romaine lettuce, and green sesame leaves) grown in organic and conventional systems were collected from various areas in korea and examined using standard culture methods to compare the microbiological quality of the produce grown in the two agricultural systems. the 354 samples of these leafy vegetables were ...201425198606
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 ...201020226552
microbial quality of bagged baby spinach and romaine lettuce: effects of top versus bottom sampling.contamination with escherichia coli o157:h7 and salmonella have called into question the safety and microbial quality of bagged ready-to-eat leafy greens. this study expands on previous findings that these goods have high total bacteria counts (tbc) and coliform counts, variation in counts among different lots, that escherichia coli is present, and disparities in counts when bags are top or bottom sampled. nearly 100 bags of baby spinach and hearts of romaine lettuce from a single brand were su ...201222221365
prevalence and characterization of escherichia coli and salmonella strains isolated from stray dog and coyote feces in a major leafy greens production region at the united states-mexico border.in 2010, romaine lettuce grown in southern arizona was implicated in a multi-state outbreak of escherichia coli o145:h28 infections. this was the first known shiga toxin-producing e. coli (stec) outbreak traced to the southwest desert leafy green vegetable production region along the united states-mexico border. limited information exists on sources of stec and other enteric zoonotic pathogens in domestic and wild animals in this region. according to local vegetable growers, unleashed or stray d ...201425412333
differences in the binding of human norovirus to and from romaine lettuce and raspberries by water and electrolyzed waters.food contamination by human norovirus (hnov) is a major cause of gastrointestinal disease. we evaluated the effectiveness of removing inoculated hnov from the surfaces of raspberries and romaine lettuce by a simple wash in tap water and in different forms of electrolyzed water (ew), including acidic ew (aew), neutral ew (new), and basic ew (bew). a simple rinsing or soaking in water was able to remove >95% of hnov from surface-inoculated raspberries. in contrast, only 75% of hnov was removed fro ...201121819668
shoot injury increases the level of persistence of salmonella enterica serovar sofia and listeria innocua on cos lettuce and of salmonella enterica serovar sofia on chive.minor shoot injury significantly (p < 0.05) increased the level at which salmonella enterica serovar sofia persisted on cos lettuce in the greenhouse. initial mean counts of the salmonella on the injured and uninjured cos lettuce were on the order of 6 log cfu/g. after 3 days, the mean count decreased to 4.8 log cfu/g on the injured plants compared with the significantly (p < 0.05) smaller count of 3.4 log cfu/g on the uninjured plants. by the end of the 3-week experiment, the count from the inj ...201526613909
effects of abiotic and biotic stresses on the internalization and dissemination of human norovirus surrogates in growing romaine lettuce.human norovirus (nov) is the major causative agent of fresh-produce-related outbreaks of gastroenteritis; however, the ecology and persistence of human nov in produce systems are poorly understood. in this study, the effects of abiotic and biotic stresses on the internalization and dissemination of two human nov surrogates (murine norovirus 1 [mnv-1] and tulane virus [tv]) in romaine lettuce were determined. to induce abiotic stress, romaine lettuce was grown under drought and flood conditions t ...201525956773
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 ...201222260117
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 ...201223498188
isolation of shiga toxin-producing escherichia coli from fresh produce using stec heart infusion washed blood agar with mitomycin-c.the ability to detect and isolate shiga toxin-producing escherichia coli (stec) remains a major challenge for food microbiologists. although methods based on nucleic acids and antibodies have improved detection of stecs in foods, isolation of these bacteria remains arduous. stec isolation is necessary for matching food, environmental, and clinical isolates during outbreak investigations and for distinguishing between pathogenic and nonpathogenic organisms. stec heart infusion washed blood agar w ...201223127712
instantlabs® e. coli o157 food safety kit.the instantlabs® e. coli o157 food safety kit was validated against the international organization for standardization reference method 16654 for the detection of escherichia coli o157. the matrixes, raw ground beef, raw beef trim, romaine lettuce, pasteurized apple juice, and raw ground chicken, were inoculated with appropriate cfu/test portion of e. coli o157 to generate fractional positives (5-15) in 20 inoculated samples. the matrixes were co-inoculated with salmonella at 2-5 times the level ...201525857881
factors affecting radiation d-values (d₁₀) of an escherichia coli cocktail and salmonella typhimurium lt2 inoculated in fresh produce.this study evaluated the effect of produce type, resuspension medium, dose uniformity ratio (dur), and sample preparation conditions (tissue exposure, map, anoxia) on the d₁₀ -value of an escherichia coli cocktail (baa-1427, baa-1428, and baa-1430) and salmonella typhimurium lt2 inoculated on the surfaces of tomato, cantaloupe, romaine lettuce, and baby spinach. produce at room temperature were irradiated using a 1.35 mev van de graaf electron beam accelerator at 0.2 to 0.9 kgy. the d₁₀-values f ...201222393921
stability of bovine coronavirus on lettuce surfaces under household refrigeration conditions.fecal suspensions with an aerosol route of transmission were responsible for a cluster of severe acute respiratory syndrome (sars) cases in 2003 in hong kong. based on that event, the world health organization recommended that research be implemented to define modes of transmission of sars coronavirus through sewage, feces, food and water. environmental studies have shown that animal coronaviruses remain infectious in water and sewage for up to a year depending on the temperature and humidity. i ...201122265299
downy mildew disease promotes the colonization of romaine lettuce by escherichia coli o157:h7 and salmonella enterica.downy mildew, a plant disease caused by the oomycete bremia lactucae, is endemic in many lettuce-growing regions of the world. invasion by plant pathogens may create new portals and opportunities for microbial colonization of plants. the occurrence of outbreaks of escherichia coli o157:h7 (eco157) and salmonella enterica typhimurium (s. typhimurium) infections linked to lettuce prompted us to investigate the role of downy mildew in the colonization of romaine lettuce by these human pathogens und ...201525648408
Efficacy of a novel sanitizer composed of lactic acid and peroxyacetic acid against single strains of nonpathogenic Escherichia coli K-12, Listeria innocua, and Lactobacillus plantarum in aqueous solution and on surfaces of romaine lettuce and spinach.A novel sanitizer composed of lactic acid and peroxyacetic acid (LA-PAA) was developed as an alternative to chlorinated water (CW) for fresh produce processing. Single strains of Lactobacillus plantarum, nonpathogenic Escherichia coli K-12, and Listeria innocua were used to demonstrate the microbial efficacy of LA-PAA. LA-PAA achieved a >7.8-log reduction of L. innocua and L. plantarum suspended in water at 4°C for 20 s, and LA, PAA, and CW achieved reductions of 0.4, 4.8, and 2.7 log, respectiv ...201121902915
roka listeria detection method using transcription mediated amplification to detect listeria species in select foods and surfaces. performance tested method(sm) 011201.the roka listeria detection assay was compared to the reference culture methods for nine select foods and three select surfaces. the roka method used half-fraser broth for enrichment at 35 +/- 2 degrees c for 24-28 h. comparison of roka's method to reference methods requires an unpaired approach. each method had a total of 545 samples inoculated with a listeria strain. each food and surface was inoculated with a different strain of listeria at two different levels per method. for the dairy produ ...201223451384
leaf microbiota in an agroecosystem: spatiotemporal variation in bacterial community composition on field-grown lettuce.the presence, size and importance of bacterial communities on plant leaf surfaces are widely appreciated. however, information is scarce regarding their composition and how it changes along geographical and seasonal scales. we collected 106 samples of field-grown romaine lettuce from commercial production regions in california and arizona during the 2009-2010 crop cycle. total bacterial populations averaged between 10(5) and 10(6) per gram of tissue, whereas counts of culturable bacteria were on ...201222534606
sanitizer efficacy in preventing cross-contamination of heads of lettuce during retail crisping.this study was conducted to provide information regarding mitigation of cross-contamination through the use of sanitizer during crisping at retail outlets. seven non-inoculated heads and one inoculated head (≈5 log cfu/g) of lettuce were placed into commercial sink filled with 76 l of tap water (tw), electrolyzed water (ew, free chlorine: 43 ± 6 ppm), lactic acid and phosphoric acid-based sanitizer (lpa, ph 2.89), or citric acid-based sanitizer (ca, ph 2.78) and soaked for 5 min. two subsequent ...201728213024
roles of a novel crp/fnr family transcription factor lmo0753 in soil survival, biofilm production and surface attachment to fresh produce of listeria monocytogenes.listeria monocytogenes is a foodborne bacterial pathogen and the causative agent of an infectious disease, listeriosis. l. monocytogenes is ubiquitous in nature and has the ability to persist in food processing environments for extended periods of time by forming biofilms and resisting industrial sanitization. human listeriosis outbreaks are commonly linked to contaminated dairy products, ready-to-eat meats, and in recent years, fresh produce such as lettuce and cantaloupes. we identified a puta ...201324066185
growth of escherichia coli o157:h7 and listeria monocytogenes in packaged fresh-cut romaine mix at fluctuating temperatures during commercial transport, retail storage, and display.temperature abuse during commercial transport and retail sale of leafy greens negatively impacts both microbial safety and product quality. consequently, the effect of fluctuating temperatures on escherichia coli o157:h7 and listeria monocytogenes growth in commercially-bagged salad greens was assessed during transport, retail storage, and display. over a 16-month period, a series of time-temperature profiles for bagged salads were obtained from five transportation routes covering four geographi ...201424490913
listeria monocytogenes internalizes in romaine lettuce grown in greenhouse conditions.listeria monocytogenes has been implicated in a number of outbreaks involving fresh produce, including an outbreak in 2016 resulting from contaminated packaged salads. the persistence and internalization potential of l. monocytogenes in romaine lettuce was evaluated, and the persistence of two l. monocytogenes strains was assessed on three romaine lettuce cultivars. seeds were germinated, and plants grown in three soil types (i.e., standard potting mix, autoclaved potting mix, and top soil) and ...201728271926
inactivation of escherichia coli o157:h7 and listeria monocytogenes in biofilms by pulsed ultraviolet light.the inactivation of biofilms formed by pathogenic bacteria on ready-to-eat and minimally processed fruits and vegetables by nonthermal processing methods is critical to ensure food safety. pulsed ultraviolet (puv) light has shown promise in the surface decontamination of liquid, powdered, and solid foods. in this study, the antimicrobial efficacy of puv light treatment on nascent biofilms formed by escherichia coli o157:h7 and listeria monocytogenes on the surfaces of food packaging materials, s ...201526054759
effects of washing produce contaminated with the snail and slug hosts of angiostrongylus cantonensis with three common household solutions.the emerging infectious disease angiostrongyliasis (rat lungworm disease) is caused by ingesting snails and slugs infected by the nematode angiostrongylus cantonensis. the definitive hosts of a. cantonensis are rats and the obligatory intermediate hosts are slugs and snails. many cases result from accidentally ingesting infected snails or slugs on produce (eg, lettuce). this study assessed three readily available household products as washing solutions for removing snails and slugs from produce ...201323901391
microbiological survey of locally grown lettuce sold at farmers' markets in vancouver, british columbia.increased consumer demand for fresh leafy produce has been paralleled by an increase in outbreaks and illness associated with these foods. presently, data on the microbiological quality and safety of produce harvested in the lower mainland of british columbia is lacking. therefore, fresh green, red, and romaine lettuce samples (n = 68) were obtained from five regional farmers' markets in late summer of 2012 and subsequently analyzed to determine total numbers of aerobic bacteria, coliforms, and ...201525581197
outbreak of shiga toxin-producing escherichia coli (stec) o157:h7 associated with romaine lettuce consumption, 2011.shiga toxin-producing escherichia coli (stec) o157:h7 is the causal agent for more than 96,000 cases of diarrheal illness and 3,200 infection-attributable hospitalizations annually in the united states.201323390525
dielectric barrier discharge atmospheric cold plasma inhibits escherichia coli o157:h7, salmonella, listeria monocytogenes, and tulane virus in romaine lettuce.the present study investigated the effects of dielectric barrier discharge atmospheric cold plasma (dacp) treatment on the inactivation of escherichia coli o157:h7, salmonella, listeria monocytogenes, and tulane virus (tv) on romaine lettuce, assessing the influences of moisture vaporization, modified atmospheric packaging (map), and post-treatment storage on the inactivation of these pathogens. romaine lettuce was inoculated with e. coli o157:h7, salmonella, l. monocytogenes (~6logcfu/g lettuce ...201627562348
use of whole genome sequencing and patient interviews to link a case of sporadic listeriosis to consumption of prepackaged lettuce.we report on a case of listeriosis in a patient who probably consumed a prepackaged romaine lettuce-containing product recalled for listeria monocytogenes contamination. although definitive epidemiological information demonstrating exposure to the specific recalled product was lacking, the patient reported consumption of a prepackaged romaine lettuce-containing product of either the recalled brand or a different brand. a multinational investigation found that patient and food isolates from the r ...201627296429
effects of a variety of food extracts and juices on the specific binding ability of norovirus gii.4 p particles.the effects of 13 food extracts and juices, including shellfish, fruits, and vegetables, on the binding ability of human norovirus (nov) were examined, using p particles of human nov gii.4 as a research surrogate. the enhancements (positive values) or reductions (negative values) of nov p particle detection (changes in optical density at 450 nm) in the presence of different food extracts and juices as compared with p particles diluted in phosphate-buffered saline were tested by saliva-binding, e ...201222980024
combination of cymbopogon citratus and allium cepa essential oils increased antibacterial activity in leafy vegetables.cymbopogon citratus and allium cepa essential oils (eos) are rich in terpenes and sulfur compounds respectively, both with antibacterial activity and different cell targets, supporting the idea that their combination can increase their efficacy.201727611358
multistate outbreak of escherichia coli o145 infections associated with romaine lettuce consumption, 2010.non-o157 shiga toxin-producing escherichia coli (stec) can cause severe illness, including hemolytic uremic syndrome (hus). stec o145 is the sixth most commonly reported non-o157 stec in the united states, although outbreaks have been infrequent. in april and may 2010, we investigated a multistate outbreak of stec o145 infection. confirmed cases were stec o145 infections with isolate pulsed-field gel electrophoresis patterns indistinguishable from those of the outbreak strain. probable cases wer ...201323726187
the hygroscopic biosurfactant syringafactin produced by pseudomonas syringae enhances fitness on leaf surfaces during fluctuating humidity.biosurfactant production by bacteria on leaf surfaces is poorly documented, and its role in this habitat has not been explored. therefore, we investigated the production and fitness benefits of syringafactin by pseudomonas syringae pv. syringae b728a on leaves. syringafactin largely adsorbed to the waxy leaf cuticle both when topically applied and when produced by cells on plants. syringafactin increased the rate of diffusion of water across isolated cuticles and attracted water to hydrophobic s ...201424571678
antimicrobial activity of plant essential oils against escherichia coli o157:h7 and salmonella on lettuce.foodborne outbreaks associated with the consumption of fresh produce have increased. in an effort to identify natural antimicrobial agents as fresh produce-wash, the effect of essential oils in reducing enteric pathogens on iceberg and romaine lettuce was investigated. lettuce pieces were inoculated with a five-strain cocktail of escherichia coli o157:h7 or salmonella enterica (5 log cfu/g) and then immersed in a treatment solution containing 5 ppm free chlorine, cinnamaldehyde, or sporan(®) (80 ...201323256843
complete genome sequences of two escherichia coli o145:h28 outbreak strains of food origin.escherichia coli o145:h28 strain rm12581 was isolated from bagged romaine lettuce during a 2010 u.s. lettuce-associated outbreak. e. coli o145:h28 strain rm12761 was isolated from ice cream during a 2007 ice cream-associated outbreak in belgium. here we report the complete genome sequences and annotation of both strains.201424855308
transfer of escherichia coli o157:h7 from equipment surfaces to fresh-cut leafy greens during processing in a model pilot-plant production line with sanitizer-free water.escherichia coli o157:h7 contamination of fresh-cut leafy greens has become a public health concern as a result of several large outbreaks. the goal of this study was to generate baseline data for e. coli o157:h7 transfer from product-inoculated equipment surfaces to uninoculated lettuce during pilot-scale processing without a sanitizer. uninoculated cored heads of iceberg and romaine lettuce (22.7 kg) were processed using a commercial shredder, step conveyor, 3.3-m flume tank with sanitizer-fre ...201223127700
influence of mycorrhizal fungi on fate of e. coli o157:h7 and salmonella in soil and internalization into romaine lettuce plants.the objectives of this study were to determine the influence of a symbiotic arbuscular mycorrhizal (am) fungus on persistence of salmonella and enterohemorrhagic escherichia coli o157:h7 (ehec) within soil, and survival within romaine lettuce. romaine seedlings were grown with or without am fungi. soil surrounding plants was inoculated with ca. 8 log cfu/plant of either salmonella enterica or e. coli ehec composites. samples (soil, root, and shoot) were analyzed on days 1, 8, 15 and 22 for salmo ...201525440552
fate of salmonella enterica in a mixed ingredient salad containing lettuce, cheddar cheese, and cooked chicken meat.food service and retail sectors offer consumers a variety of mixed ingredient salads that contain fresh-cut vegetables and other ingredients such as fruits, nuts, cereals, dairy products, cooked seafood, cooked meat, cured meats, or dairy products obtained from external suppliers. little is known about the behavior of enteric bacterial pathogens in mixed ingredient salads. a model system was developed to examine the fate of salmonella enterica (inoculum consisting of s. enterica serovars agona, ...201525719871
enhancing plant productivity while suppressing biofilm growth in a windowfarm system using beneficial bacteria and ultraviolet irradiation.common problems in a windowfarm system (a vertical and indoor hydroponic system) are phytopathogen infections in plants and excessive buildup of biofilms. the objectives of this study were (i) to promote plant health by making plants more resistant to infection by using beneficial biosurfactant-producing pseudomonas chlororaphis around the roots and (ii) to minimize biofilm buildup by ultraviolet (uv) irradiation of the water reservoir, thereby extending the lifespan of the whole system with min ...201525996177
quantitative transfer of escherichia coli o157:h7 to equipment during small-scale production of fresh-cut leafy greens.postharvest contamination and subsequent spread of escherichia coli o157:h7 can occur during shredding, conveying, fluming, and dewatering of fresh-cut leafy greens. this study quantified e. coli o157:h7 transfer from leafy greens to equipment surfaces during simulated small-scale commercial processing. three to five batches (22.7 kg) of baby spinach, iceberg lettuce, and romaine lettuce were dip inoculated with a four-strain cocktail of avirulent, green fluorescent protein-labeled, ampicillinre ...201222980000
comparison of the microbiological quality of environmentally friendly and conventionally grown vegetables sold at retail markets in korea.fresh produce is usually eaten raw without cooking or heating, which may increase the probability of foodborne infection. the microbiological quality of 11 types of fresh, raw vegetables (romaine lettuce, sesame leaves, crown daisy, garlic chives, iceberg lettuce, cabbage, broccoli, leek, chili pepper, capsicum, and zucchini) purchased at retail markets in iksan, korea as affected by cultivation method (environmentally friendly vegetables [organic, pesticide-free, and low-pesticide vegetables] a ...201425124136
molecular mapping of high resistance to bacterial leaf spot in lettuce pi 358001-1.lettuce (lactuca sativa l.) is a diploid (2n = 18) with a genome size of 2,600 mbp, and belongs to the family compositae. bacterial leaf spot (bls), caused by xanthomonas campestris pv. vitians, is a major disease of lettuce worldwide. leaf lettuce pi 358001-1 has been characterized as an accession highly resistant to bls and has white seed. in order to understand inheritance of the high resistance in this germplasm line, an f3 population consisting of 163 families was developed from the cross p ...201627454703
behavioral responses of schistocerca americana (orthoptera: acrididae) to azadirex (neem)-treated host plants.azadirex (azadirachtin and other biologically active extracts from neem trees) has been shown to have considerable potential to be used in integrated pest management systems based on its growth regulator/insecticide properties. less well known are the antifeedant properties. the feeding-deterrent properties of a commercial azadirex formulation (azatrol ec) were evaluated using both no-choice and choice tests, the american grasshopper, schistocerca americana (drury), and four host plants [savoy c ...200717370818
lettuce and chicory byproducts as a source of antioxidant phenolic extracts.a process to obtain enriched antioxidant phenolic extracts from lettuce (baby, romaine, and iceberg cultivars) and chichory byproducts as a way to valorize these byproducts was developed. two extraction protocols using water and methanol as solvent were used. amberlite xad-2 nonionic polymeric resin was used to purify the extracts. the extraction yield, phenolic content, and phenolic yield were evaluated as well as the antioxidant capacity of the extracts (dpph, abts, and frap assays). baby and ...200415291483
host plant resistance in romaine lettuce affects feeding behavior and biology of trichoplusia ni and spodoptera exigua (lepidoptera: noctuidae).lettuce quality and yield can be reduced by feeding of several lepidopterous pests, particularly cabbage looper, trichoplusia ni (hübner), and beet armyworm, spodoptera exigua (hübner) (lepidoptera: noctuidae). host plant resistance to these insects is an environmentally sound adjunct to conventional chemical control. in this study we compared the survival, development, and feeding behavior of cabbage looper and beet armyworm on two romaine lettuce cultivars, resistant 'valmaine' and susceptible ...200617195688
evaluation of two loop-mediated isothermal amplification methods for the detection of salmonella enteritidis and listeria monocytogenes in artificially contaminated ready-to-eat fresh produce.in the present study, the effectiveness of two loop-mediated isothermal amplification (lamp) assays was evaluated. samples of romaine lettuce, strawberries, cherry tomatoes, green onions and sour berries were inoculated with known dilutions (10(0)-10(8) cfu/g of produce) of s. enteritidis and l. monocytogenes. with lamp, assay pathogens can be detected in less than 60 min. the limits of detection of s. enteritidis and l. monocytogenes depended on the food sample tested and on the presence of enr ...201527800413
evaluation of rapid screening techniques for detection of salmonella spp. from produce samples after pre-enrichment according to fda bam and a short secondary enrichment.conventional detection of salmonella from foods involves enrichment and isolation on selective media which can significantly lengthen time to result. the objective of this study was to evaluate the utility of an accelerated plating procedure and the use of rapid screening devices for salmonella detection. fresh produce was inoculated with salmonella at ~2·5, ~7·5 and ~25 cfu sample(-1) . after 24 h pre-enrichment, subcultures were made into tt and rv broths and further incubated at 42°c for an a ...201525809127
quantifying the sensitivity of scent detection dogs to identify fecal contamination on raw produce.consumption of raw produce commodities has been associated with foodborne outbreaks in the united states. in a recent centers for disease control and prevention report outlining the incidence of food-related outbreaks from 1998 to 2008, produce of all kinds were implicated in 46% of illnesses and 23% of deaths. methods that quickly identify fecal contamination of foods, including produce, will allow prioritization of samples for testing during investigations and perhaps decrease the time require ...201424405993
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