Rind Surface Research Articles

The Anatomical Differences and Physiological Responses of Sunburned Satsuma Mandarin (Citrus unshiu Marc.) Fruits.

Sunburn causes fruit browning and other physiological symptoms, reducing fruit production and quality. Therefore, we aimed to investigate the anatomical differences and abiotic stress responses in ‘Nichinan 1 gou’ satsuma mandarin (Citrus unshiu Marc.) according to the severity of sunburn damage (five grades: control, no sunburn; I to IV, increasing severity of sunburn). Additionally, the quality of sunburned and non-sunburned fruits was compared, and the sunburn-inducing temperature was estimated. Anatomical observations confirmed that with increased severity of symptoms, the damage to fruit rind surface and oil glands was increased. In the analysis of peel pigments, chlorophyll content in the rind gradually decreased compared with IV, whereas the carotenoid content gradually increased up to III. The flavonoid content in the peel and pulp was the highest in III. In the 1,1-diphenyl-2-picrylhydrazyl and 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radical analyses, the IC50 (the concentration of compound at which the percentage of inhibition is 50%) value was the lowest in grade III in peel or IV in pulp, indicating a high free radical scavenging ability. The fruit quality analysis between sunburned and non-sunburned fruits showed differences in total soluble solid content, total acidity, firmness, coloration, and free sugar and organic acid contents, indicating a significant effect on fruit quality. In the heat tolerance tests on fruit rind in the laboratory and field, the damage was confirmed at temperatures above 47 °C.

Encapsulated Plant-Derived Antimicrobial Reduces Enteric Bacterial Pathogens on Melon Surfaces during Differing Contamination and Sanitization Treatment Scenarios

This study aimed to quantify survival in Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium isolates on melon rind surface samples achieved by sanitizer treatment under three differing melon contamination and sanitization scenarios. Sanitizing treatments consisted of the plant-derived antimicrobial (PDA) essential oil component (EOC) geraniol (0.5 wt.%) entrapped in the polymeric surfactant Pluronic F-127 (GNP), 0.5 wt.% unencapsulated geraniol (UG), 200 mg/L hypochlorous acid at pH 7.0 (HOCl), and a sterile distilled water wash (CON). The experimental contamination and sanitization scenarios tested were: (1) pathogen inoculation preceded by treatment; (2) the pathogen was inoculated onto samples twice with sanitizing treatment applied in between inoculation events; or (3) pathogen inoculation followed by sanitizing treatment. Reductions in the numbers of surviving pathogens were dependent on the sanitizing treatment, the storage period, or the interaction of these effects. GNP treatment provided the greatest reductions in surviving pathogen counts on melon rinds, but these did not regularly statistically differ from those achieved by HOCl or UG treatment. GNP treatment provided the best pathogen control under differing conditions of pre- and/or post-harvest cross-contamination and can be applied to reduce the risk of pathogen transmission on melon rinds.

Abrasive brushing reduces pathogen biofilms at cantaloupe rind surface

Foodborne pathogens constitute a major food safety risk for cantaloupe, and pathogen biofilms formed are particularly difficult to remove. The goal of this study was to evaluate abrasive brushing in removing biofilms from cantaloupe surface using Listeria monocytogenes V7 and Salmonella enterica serovar Typhimurium ATCC 13311 as models. Cantaloupe rind pieces were inoculated and then subjected to 30 min or 24 h incubations. The incubated rind pieces were subject to different washing and/or brushing procedures and then the bacterial cells were enumerated. Cryo-SEM showed planktonic cells after 30 min incubation, whereas biofilms formed at rind surfaces after 24 h incubation. For L. monocytogenes 30 min incubation group, the log reductions were 1.4 for brushing, 2.1 for brushing with diatomaceous earth (DE), 2.8 for peroxyacetic acid (PAA) washing, 4.2 for brushing with PAA, and 4.0 for brushing with DE and PAA. In contrast, for the 24 h incubation group, the log reductions were 0.4 for brushing, 1.5 for brushing with DE, 1.1 for PAA washing, 1.6 for brushing with PAA, and 3.0 for brushing with DE and PAA. Similar results were observed for the S. Typhimurium group. These outcomes showed the pathogen-removal efficacy of brushing with DE (abrasive brushing) in the presence of biofilms, suggesting the potential application of abrasive brushing in cleaning cantaloupe for improved food safety.

MUTU BUAH JERUK KALAMANSI PADA BERBAGAI TINGKAT SERANGAN PENYAKIT KUDIS

[FRUIT QUALITIES OF CALAMANSI UNDER DIFFERENT SCAB DISEASE SEVERITIES]. Citrus scab caused by Elsinoe fawcettii dan Elsinoe australis fungi is an important disease for calamansi lime. The pathogen can result creamy-yellowish, raised, rounded, corky scabs appear on the rind surface of the fruit that reduces marketabilityof the fruit. The objective of this study was to evaluate the development and intensity of scab and their effects on the physical and chemical qualities of calamansi fruits. The observations were made on 30 fruit samples collected from farmer’s calamansi orchard for the development and intensity of disease symptoms, fruit appearances, juice content, and total soluble solids of the juice. The results showed that the pathogen began to attack on early fruit set phase. The intensity of the disease at the beginning of the observation was 11.06% and increased to 58.18% with an average rate of attack intensity of 14.54%. The disease reduced the fruit weight, fruit diameter, juice volume and total soluble solid levels.

Deteksi Kecacatan Permukaan Buah Manggis Menggunakan Metode Deep Learning dengan Konvolusi Multilayer

Mangosteen is one of Indonesian potential export fruits. Nevertheless, mangosteens quality is compulsary. A good quality fruit surface is needed in export fruit. This is the reason of this research to detect the flaw in rind surface, particularly mangosteen. Some researcher has been done many type of image processing for fruit detection. However, there aren’t any research for mangosteen rind detection especially used Deep Learning. This research used CNN (Convolutional Neural Network) as deep learning method to detect mangosteen rind surface. Our research is to find configuration which was the best accurancy value. The rind detection calcuted between epoch and layer to obtain maximum accurancy value. This method achieved maximum value by parameter 4 layer and epoch value of 30. From our experiment, the test result for rind detection was 98% accurancy.

Biofilm of Escherichia coli O157:H7 on cantaloupe surface is resistant to lauroyl arginate ethyl and sodium hypochlorite

Biofilms formed by Escherichia coli O157:H7 on cantaloupe rind were characterized in this study. Cantaloupe rind pieces inoculated with E. coli O157:H7 B6-914 was sampled after 2, 12, and 24h incubation for imaging with cryo-scanning electron microscopy (Cryo-SEM) or treating with lauroyl arginate ethyl (LAE) or sodium hypochlorite (SHC). Cryo-SEM images showed that E. coli O157:H7 formed a biofilm within 12h on the rind surface. For rind samples treated with LAE or SHC, the residual cell counts were significantly different (p<0.05) between 2 and 12h incubation, and between 2 and 24h of incubation. For the 2h incubation samples, E. coli O157:H7 was undetectable (>5-log reduction) after treatment with 2000μg/mL of LAE or SHC. In contrast, for 12h incubation samples, 2000μg/mL of LAE or SHC could only achieve 1.74 or 1.86-log reduction, respectively. The study showed the low efficacy of LAE and SHC on cantaloupe rind surface to reduce the E. coli biofilm, suggesting the needs for cantaloupe cleaning methods beyond washing with conventional antimicrobial agents.

Involvement of membrane degradation in response to oleocellosis induced by exogenous orange oil in citrus fruit

Navel oranges (Citrus sinensis L. Osbeck) were treated with pure orange oil to simulate the natural cause of oleocellosis and to elucidate the mechanism involving in fruit injury caused by orange oil. Results showed that no injury was found on the rind surface of control fruits during storage. By contrast, application of exogenous orange oil onto the surface of fruits could rapidly induce peel injury. Moreover, the severity of injury increased during storage. At the end of the storage time, the collapse and discolouration scores were 17.3 and 16.7 times higher than those at 4 h after treatment. Oil treatment caused fruit membrane degradation by increasing the activities of phospholipase D and lipoxygenase, reducing the ratio of unsaturated/saturated fatty acids and enhancing the levels of hydrogen peroxide, superoxide anion, malonaldehyde, and electrolyte leakage. In addition, the treatment reduced the activities of superoxide dismutase and catalase, as well as suppressed the ascorbate acid–glutathione cycle, which led to the efficiency loss of the reactive oxygen species scavenging system.

Pathogen biofilm formation on cantaloupe surface and its impact on the antibacterial effect of lauroyl arginate ethyl

Pathogen biofilm at fruit surface may pose a particular risk to food safety. In this study, the biofilms of Listeria monocytogenes V7 and Salmonella enterica serovar Typhimurium ATCC 13311 on cantaloupe fruit surface were visualized, and the resistance of biofilms against lauroyl arginate ethyl (LAE, an antibacterial compound) was evaluated. Each bacterium was inoculated on isolated cantaloupe rind surfaces at 105–106 CFU/cm2 and after incubation for 2, 12, 24, and 48 h, the surfaces were imaged using cryo-scanning electron microscopy (Cryo-SEM). The images showed that both pathogens formed biofilms on rind surfaces, with S. Typhimurium forming biofilm in 12 h and L. monocytogenes cells starting to aggregate in 2 h. For the inoculated rind surfaces treated with LAE, the cell counts were affected by both the incubation time and LAE concentration. For rind surface with 2 h incubation of S. Typhimurium, 400 and 800 μg/mL LAE was able to achieve >2.00 log reduction; however, 12 h incubation required 1600 and 2000 μg/mL LAE for >2.00 log reduction. In contrast, even the highest LAE concentration (2000 μg/mL) was unable to cause 1.00 log reduction for L. monocytogenes regardless the incubation time applied. The results showed that the biofilms of both bacteria substantially reduced LAE efficacy, and that the biofilm of L. monocytogenes was more resistant than that of S. Typhimurium.

Effect of Hydrogen Peroxide in Combination with Minimal Thermal Treatment for Reducing Bacterial Populations on Cantaloupe Rind Surfaces and Transfer to Fresh-Cut Pieces

Surface structure and biochemical characteristics of bacteria and produce play a major role in how and where bacteria attach, complicating decontamination treatments. Whole cantaloupe rind surfaces were inoculated with Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes at 10(7) CFU/ml. Average population size of Salmonella, Escherichia coli O157:H7, and L. monocytogenes recovered after surface inoculation was 4.8 ± 0.12, 5.1 ± 0.14, and 3.6 ± 0.13 log CFU/cm(2), respectively. Inoculated melons were stored at 5 and 22°C for 7 days before washing treatment interventions. Intervention treatments used were (i) water (H2O) at 22°C, (ii) H2O at 80°C, (iii) 3% hydrogen peroxide (H2O2) at 22°C, and (iv) a combination of 3% H2O2 and H2O at 80°C for 300 s. The strength of pathogen attachment (SR value) at days 0, 3, and 7 of storage was determined, and then the efficacy of the intervention treatments to detach, kill, and reduce transfer of bacteria to fresh-cut pieces during fresh-cut preparation was investigated. Populations of E. coli O157:H7 attached to the rind surface at significantly higher levels (P < 0.05) than Salmonella and L. monocytogenes, but Salmonella exhibited the strongest attachment (SR value) at all days tested. Washing with 3% H2O2 alone led to significant reduction (P < 0.05) of bacteria and caused some changes in bacterial cell morphology. A combination treatment with H2O and 3% H2O2 at 8°C led to an average 4-log reduction of bacterial pathogens, and no bacterial pathogens were detected in fresh-cut pieces prepared from this combination treatment, including enriched fresh-cut samples. The results of this study indicate that the microbial safety of fresh-cut pieces from treated cantaloupes was improved at day 6 of storage at 5°C and day 3 of storage at 10°C.

Effectiveness of Broad-Spectrum Chemical Produce Sanitizers against Foodborne Pathogens as In Vitro Planktonic Cells and on the Surface of Whole Cantaloupes and Watermelons

Over the past few years, foodborne disease outbreaks linked to enteric pathogens present on cantaloupe and watermelon surfaces have raised concerns in the melon industry. This research evaluated the effectiveness of commercially available produce sanitizers against selected foodborne pathogens, both in cell suspensions and on the outer rind surface of melons. The sanitizers (65 and 200 ppm of chlorine, 5 and 35% hydrogen peroxide, 5 and 50 ppm of liquid chlorine dioxide, various hydrogen peroxide-acid combinations, 0.78 and 2.5% organic acids, and 300 ppm of quaternary ammonium) were tested against Escherichia coli O157:H7, Listeria monocytogenes, Salmonella, and non-O157 Shiga toxin-producing E. coli (O26, O45, O103, O111, O121, and O145). The cell suspension study revealed the ability of all tested sanitizers to reduce all selected pathogens by 0.6 to 9.6 log CFU/ml in vitro. In the melon study, significant differences in pathogen reduction were observed between sanitizers but not between melon types. The most effective sanitizers were quaternary ammonium and hydrogen peroxide-acid combinations, with 1.0- to 2.2-log CFU/g and 1.3- to 2.8-log CFU/g reductions, respectively, for all pathogens. The other sanitizers were less effective in killing the pathogens, with reductions ranging from 0.0 to 2.8 log CFU/g depending on pathogen and sanitizer. This study provides guidance to the melon industry on the best produce sanitizers for use in implementing a broad-spectrum pathogen intervention strategy.

Inferring alteration conditions on Mars: Insights from near-infrared spectra of terrestrial basalts altered in cold and hot arid environments

Can information on the Martian environmental conditions prevailing during the alteration of its basaltic crust be inferred from near-infrared (NIR) spectra? In order to determine whether basalts altered under arid conditions but different temperatures have different spectral signatures, NIR spectra of basalts altered in cold (Udokan volcanic field, Siberia) and hot (Ogaden Basin, Ethiopia) environments were obtained. The NIR spectra of the alteration rind surface and the internal part of the studied samples are similar, suggesting that the NIR spectra of Martian bulk rocks may be of limited help in identifying paleoenvironment conditions. Bulk rock spectra analysis reveals, however, that spectra of the least altered rocks display clear absorption bands of smectites, suggesting that a distinction between clay minerals in weakly weathered basalts and clay-rich formations cannot be based solely on analysis of infrared spectra obtained from orbit. Additional compositional information can be retrieved from rock powder spectra – zeolites present in the Udokan basalt spectra might be used to infer composition and temperature of the fluids from which they precipitated. The presence of calcite and iddingsite is ascertained by other methods, but they are not apparent in bulk rock spectra and only weakly apparent in powder spectra. The basalt samples studied display alteration products that reflect their different alteration histories; nevertheless no criterion has been found that would help in identifying the origin of the weathering water – subsurface, rainfall, or snowfall.

Clast rind analysis using multi-high resolution instrumentation.

Clast weathering rinds, formed over varying lengths of time (10(2) -10(6) years) in terrestrial environments, are measured to provide relative ages for deposits in glacial sequences, specifically to differentiate between glaciations, occasionally within glaciations. Other studies have sought to reveal weathering rates in non-glacial environments using microscopic techniques and isotopes. Recent analyses of clast rinds from tropical, mid-latitude and polar areas reveal an astounding corpus of organic and inorganic paleoenvironmental data derived from atmospheric and biospheric elements active in weathering clasts in glacial deposits over varying lengths of time. In some cases, extreme biochemical products, observed within the rind matrix, are seen to play a role in adjusting redox potentials important in the production of oxides and hydroxides and biominerals with variable compositions. Up to recently, rind analysis has been limited to use of the light microscope and SEM/EDS, which has greatly advanced our understanding of compositional inter-linkages of minerals and biotic elements, but only along horizontal axes within the rind. A test involving rind surface composition using vertical axis nanospaced layer analysis within rinds using focused ion beam (FIB) and TEM/STEM/EDX imagery and chemistry illustrates the power of data acquisition within the three-dimensional weathered archive. SCANNING 38:202-212, 2016. © 2015 Wiley Periodicals, Inc.

Efficacy of Sanitizer Treatments on Survival and Growth Parameters of Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes on Fresh-Cut Pieces of Cantaloupe during Storage

For health reasons, people are consuming fresh-cut fruits with or without minimal processing and, thereby, exposing themselves to the risk of foodborne illness if such fruits are contaminated with bacterial pathogens. This study investigated survival and growth parameters of Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, and aerobic mesophilic bacteria transferred from cantaloupe rind surfaces to fresh-cut pieces during fresh-cut preparation. All human bacterial pathogens inoculated on cantaloupe rind surfaces averaged ~4.8 log CFU/cm2, and the populations transferred to fresh-cut pieces before washing treatments ranged from 3 to 3.5 log CFU/g for all pathogens. A nisin-based sanitizer developed in our laboratory and chlorinated water at 1,000 mg/liter were evaluated for effectiveness in minimizing transfer of bacterial populations from cantaloupe rind surface to fresh-cut pieces. Inoculated and uninoculated cantaloupes were washed for 5 min before fresh-cut preparation and storage of fresh-cut pieces at 5 and 10°C for 15 days and at 22°C for 24 h. In fresh-cut pieces from cantaloupe washed with chlorinated water, only Salmonella was found (0.9 log CFU/g), whereas E. coli O157:H7 and L. monocytogenes were positive only by enrichment. The nisin-based sanitizer prevented transfer of human bacteria from melon rind surfaces to fresh-cut pieces, and the populations in fresh-cut pieces were below detection even by enrichment. Storage temperature affected survival and the growth rate for each type of bacteria on fresh-cut cantaloupe. Specific growth rates of E. coli O157:H7, Salmonella, and L. monocytogenes in fresh-cut pieces were similar, whereas the aerobic mesophilic bacteria grew 60 to 80% faster and had shorter lag phases.

Involvement of lycopene in the induction of tolerance to chilling injury in grapefruit

Grapefruit are among the more sensitive Citrus varieties likely to develop chilling injury (CI) symptoms during postharvest storage at low temperatures. Comparative observations of the incidence of CI in fruit of white Marsh (MSH) and red Star Ruby (SR) grapefruit during postharvest storage at 2°C plus 7 days at 20°C to simulate shelf-life revealed that (1) the former was consistently more sensitive to CI, developing cold damage uniformly throughout the whole rind surface, and (2) more strikingly, CI symptoms in fruit of SR grapefruit were restricted to the yellow areas of the rind and the red-colored zones were almost absent of cold damage. This tolerance to CI in red flavedo was associated with high carotenoid (×2) and lycopene (×14) contents, as compared with yellow-colored flavedo. Absence of chilling damage in red areas of SR grapefruit rind was confirmed by cellular ultrastructure observations, in which these epidermal cells were intact, with a well-defined structure and compact vacuoles filled with content. Cells of yellow-colored tissue developing CI, were collapsed, with a contracted vacuole and shrinking organelles. To explore whether the tolerance to CI in red areas of grapefruit rind was due to an elevated lycopene concentration, chemical and environmental stimulation of this carotenoid was performed in fruit of both grapefruit varieties. Application of the inhibitor of the lycopene cyclase activity, CPTA (2-(4-chlorophenylthio) triethylamine hydrochloride) induced red coloration, increased lycopene accumulation (×32) and significantly delayed development of CI symptoms in the rind the CI-sensitive MSH. Bagging of SR grapefruit enhanced a homogenous red coloration and substantially induced lycopene accumulation (×75). CI symptoms in bagged fruit were notably delayed and reduced, as compared with non-bagged yellow fruit, upon subsequent storage at 2°C for up to 58 days and 7 days at 20°C. Analysis of the expression of ethylene biosynthetic genes (ACS1, ACS2 and ACO) revealed a significant induction in chilling-damaged tissue of both varieties that was almost absent in red chilling-tolerant tissue. Similarly, accumulation of transcripts of the ethylene receptors ETR1 and ETR3 were also associated with chilling damage, but a cold factor appears to also mediate the expression of these genes. Taken together, our results indicate that high lycopene concentration appears to be responsible for the induction of tolerance to chilling in the red-colored areas of the flavedo of grapefruit during postharvest storage at low temperatures.

Surface survival and internalization of salmonella through natural cracks on developing cantaloupe fruits, alone or in the presence of the melon wilt pathogen Erwinia tracheiphila.

Outbreaks of foodborne illness attributed to the consumption of Salmonella-tainted cantaloupe have occurred repeatedly, but understanding of the ecology of Salmonella on cantaloupe fruit surfaces is limited. We investigated the interactions between Salmonella enterica Poona, the plant pathogenic bacterium Erwinia tracheiphila, and cantaloupe fruit. Fruit surfaces were inoculated at the natural cracking stage by spreading S. enterica and E. tracheiphila, 20 µl at 107 cfu/ml, independently or together, over a 2×2 cm rind area containing a crack. Microbial and microscopic analyses were performed at 0, 9 and 24 days post inoculation (DPI). Even at 24 DPI (fruit maturity) S. enterica was detected on 14% and 40% of the fruit inoculated with S. enterica alone and the two-pathogen mixture, respectively. However, the population of S. enterica declined gradually after initial inoculation. E. tracheiphila, inoculated alone or together with Salmonella, caused watersoaked lesions on cantaloupe fruit; but we could not conclude in this study that S. enterica survival on the fruit surface was enhanced by the presence of those lesions. Of fruit inoculated with E. tracheiphila alone and sampled at 24 DPI, 61% had watersoaked lesions on the surface. In nearly half of those symptomatic fruits the watersoaking extended into the sub-rind mesocarp, and E. tracheiphila was recovered from that tissue in 50% of the symptomatic fruit. In this work, E. tracheiphila internalized through natural cracks on developing fruits. S. enterica was never detected in the fruit interior (ca. 2–3 mm below rind surface) under the limited conditions of our experiments, but the possibility that it, or other human pathogens that contaminate fresh produce, might also do so should be investigated under a wider range of conditions and produce types.

Evaluation of levulinic acid and sodium dodecyl sulfate as a sanitizer for use in processing Georgia-grown cantaloupes.

Freshly harvested Georgia-grown cantaloupes (Cucumis melo L. var. reticulatus cv. Athena and Atlantis) were spot inoculated with 100 μl of a five-strain mixture of Salmonella enterica serovar Poona (9 log CFU/ml) at the stem scar and on the netted rind and then subjected to no treatment (control) or a 6-min treatment (tank only) in water, 120 ppm of chlorine (pH 7.0), 1% levulinic acid plus 0.1% sodium dodecyl sulfate (SDS; pH 3.0), or 2% levulinic acid plus 0.2% SDS (pH 3.0). The log reduction for the tank-only treatments was 0.31, 0.59, 1.32, and 1.37 log CFU/g at the stem scar and 0.97, 1.59, 2.06. and 3.37 log CFU/g on the netted rind for water, chlorine, 1% levulinic acid plus 0.1% SDS, and 2% levulinic acid plus 0.2% SDS, respectively. A greater log reduction was observed for the cantaloupe surface tissue with the water, chlorine, and 2% levulinic acid plus 0.2% SDS treatments when additional sanitizer (2 ml) and brushing (to simulate cantaloupes tumbling over brushes on the processing line) were added to the dump tank treatment. The stem scar tissue reductions were 0.90, 1.69, and 1.53 log CFU/g, whereas the netted rind reductions were 1.56, 2.50, and 4.47 log CFU/g after treatment with water, chlorine, and 2% levulinic acid plus 0.2% SDS, respectively. These data suggest that 2% levulinic acid plus 0.2% SDS is effective for reducing Salmonella on the netted rind surface of cantaloupes. However, neither 2% levulinic acid plus 0.2% SDS nor 120 ppm of chlorine substantially reduced Salmonella on stem scar tissue.

Assessment of root uptake and systemic vine-transport of Salmonella enterica sv. Typhimurium by melon (Cucumis melo) during field production

Among melons, cantaloupes are most frequently implicated in outbreaks and surveillance-based recalls due to Salmonella enterica. There is limited but compelling evidence that associates irrigation water quality as a significant risk of preharvest contamination of melons. However, the potential for root uptake from water and soil and subsequent systemic transport of Salmonella into melon fruit is uncharacterized. The aim of this work was to determine whether root uptake of S. enterica results in systemic transport to fruit at high doses of applied inoculum through sub-surface drip and furrow irrigation during field production of melons. Cantaloupe and honeydew were grown under field conditions, in a silt clay loam soil using standard agronomic practices for California. An attenuated S. enterica sv. Typhimurium strain was applied during furrow irrigation and, in separate plots, buried drip-emitter lines delivered the inoculum directly into the established root zone. Contamination of the water resulted in soil contamination within furrows however Salmonella was not detected on top of the beds or around melon roots of furrow-irrigated rows demonstrating absence of detectable lateral transfer across the soil profile. In contrast, positive detection of the applied isolate occurred in soil and the rhizosphere in drip injected plots; survival of Salmonella was at least 41days. Despite high populations of the applied bacteria in the rhizosphere, after surface disinfection, internalized Salmonella was not detected in mature melon fruit (n=485). Contamination of the applied Salmonella was detected on the rind surface of melons if fruit developed in contact with soil on the sides of the inoculated furrows. Following an unusual and heavy rain event during fruit maturation, melons collected from the central area of the beds, were shown to harbor the furrow-applied Salmonella. Delivery of Salmonella directly into the peduncle, after minor puncture wounding, resulted in detection of applied Salmonella in the sub-rind tissue below the fruit abscission zone. Results indicate that Salmonella internalization from soil and vascular systemic transport to fruit is unlikely to occur from irrigation water in CA production regions, even if substantially above normal presumptive levels of contamination. Although contaminated irrigation water and subsequently soil in contact with fruit remains a concern for contamination of the external rind, results suggest an acceptable microbial indicator threshold and critical limit for the presence of Salmonella in applied water may be possible by defining appropriate microbiological standards for melon irrigation in California and regions with similar climate, soil texture, and crop management practices.

Survey of Fusarium spp. Associated with Fruit Rot of Pumpkin in Ohio

From 2000 to 2002 commercial pumpkin (Cucurbita pepo) fields in Ohio were surveyed for Fusarium fruit rot. From six counties in 2000, 2001, and 2002, a total of 43 isolates from eight farms, 84 isolates from nine farms, and 40 isolates from six farms were collected, respectively. Fusarium solani f. sp. cucurbitae race 1 was the most commonly isolated Fusarium species from infected pumpkin fruit in Ohio. Other Fusaria isolated from infected fruit included F. oxysporum, F. graminearum, and F. acuminatum. A survey of infected pumpkin fruit in the field and inoculation studies of mature, healthy pumpkin cultivar Magic Lantern in the laboratory resulted in three types of fruit rot symptoms. Type 1, caused by F. oxysporum and F. acuminatum, resulted in a slow-expanding rot just below the rind surface of the infected fruit. Type 2, caused by F. graminearum, resulted in an expanding, slightly sunken, irregular rot of the rind surface. Type 3, caused by F. solani resulted in expanding, circular sunken lesions on the fruit surface bearing white to tan sporodochia. This is the first report of F. solani f. sp. cucurbitae race 1, F. oxysporum, F. acuminatum, and F. graminearum causing fruit rot of pumpkin in Ohio. Accepted for publication 26 July 2010. Published 27 August 2010.

Immersion of Lemons into Imazalil Mixtures Heated at 50 °C Alters the Cuticle and Promotes Permeation of Imazalil into Rind Wounds

The influence of the immersion of lemon fruit in aqueous imazalil (IMZ) mixtures at 25 or 50 degrees C on the deposition and persistence of IMZ within the fruit rind and its effectiveness in controlling postharvest green mold, caused by Penicillium digitatum, was investigated. Concentrations of IMZ in the albedo tissue surrounding deep wounds in the rind were higher than the mean EC50 values for IMZ-resistant strains (1.0 microg *mL(-1)) after immersion of fruit into IMZ mixtures containing 25, 50, or 75 mg* L(-1) heated to 50 degrees C, but not those at 25 degrees C, where fungicide deposition was insufficient. IMZ residue, one day after treatment with 25, 50, or 75 mg* L(-1), was 3, 5, or 7 times higher after treatment at 50 degrees C compared to treatment at 25 degrees C. IMZ residues within the albedo of unwounded fruit treated with 25, 50, or 75 mg* L(-1) at 50 degrees C were 0.8, 1.3, or 2.0 microg * g(-1), respectively, while those similarly treated at 25 degrees C had negligible residues. Residues following treatment at 50 degrees C in the albedo did not decline during storage at 10 degrees C after 60 days. IMZ residues in the flavedo were higher than those in the albedo: after treatment with 25, 50, or 75 mg* L(-1) IMZ, they averaged 1.0, 1.2, or 2.7 microg * g(-1), respectively, after treatment at 25 degrees C, and 5.5, 7.9, or 16.2 microg * g(-1), respectively, after treatment at 50 degrees C. IMZ effectiveness as an eradicant to control green mold improved when it was heated. Green mold was reduced by 22 or 95% after treatment of lemons inoculated 1 h before immersion of lemons in IMZ at 50 mg* L(-1) at 25 or 50 degrees C, respectively. Green mold was reduced by 18 or 61% after treatment of lemons inoculated 1 day after immersion of lemons in IMZ at 50 mg* L(-1) at 25 or 50 degrees C, respectively. Scanning electron microscopy of the rind surface indicated that treatment at 50 degrees C for 2 min also caused ruptures in the cuticle.

Examination of wooden shelves used in the ripening of a raw milk smear cheese by FTIR spectroscopy

The surface of wooden shelves used in the ripening of a raw milk smear cheese was examined by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. FTIR spectra of zones of wooden shelves in contact with cheeses or not (control) were acquired. This acquisition was performed either directly after cheeses removal or after brushing with water to remove cheese compounds deposited onto wood surfaces. Their analysis revealed that the degree of similarity between the ATR-FTIR spectra of unused and cleaned by brushing wooden shelves is higher than with the spectra of non-cleaned surfaces. The spectra of non-cleaned zones where cheeses were ripened namely differed in the 920–1180 cm −1 and in the 1485–1780 cm −1 regions. These regions can be assigned to proteins and polysaccharides and thus might correspond to deposits of cheese rind surface as well as to the presence of microbial biofilms on wooden shelves. Similarities in these spectral regions with those of cheese rind support this hypothesis. These observations indicate that ATR-FTIR spectroscopy is a rapid and valuable analytical tool to directly investigate the global chemical composition of very thin films such as microbial biofilms or cheese rind deposits present on wooden shelves which are not accessible to standard chemical methods.