Unraveling the antifungal composition of bitter orange decoction against the melon pathogen Fusarium jinanense.

Bitter orange (Citrus aurantium) is an important source of essential oils with high antimicrobial activities, however the composition and antifungal potential of the decoction peels is little explored. This study assessed the peel decoction's chemical profile at the secondary metabolism level and its antifungal activity against the melon phytopathogen Fusarium jinanense. The decoction's antifungal potential was investigated using a bioassay-guided fractionation approach based on Solid-Phase Extraction (SPE) and LC-HRMS/MS analysis. Coumarins and flavones were the most abundant classes of compounds in the high-value fractions responsible for up to 61% of the mycelial inhibition of F. jinanense. Overall, this study has presented for the first time the chemical composition, the antifungal potential of the decoction of C. aurantium peels and the compounds associated with these results. This strategy can guide the exploration of under-explored food sources and add value to compounds or fractions enriched with bioactive compounds.

Aggressivity of Different Fusarium Species Causing Fruit Rot in Melons in Brazil.

Brazil is one of the largest melon (Cucumis melo) producers in the world and most of the production is exported to international markets. Currently, over 15% of Brazilian melon shipments are lost during export transportation due to Fusarium fruit rot, which is jeopardizing the livelihood of Brazilian melon producers. We focused on understanding the aggressivity of five species of Fusarium causing fruit rot on the main types of melon produced in Brazil. We also investigated the correlation between pathogenicity and fruit quality. Experiments were performed under a completely randomized experimental design, in a 5 × 8 factorial scheme, using two methods for inoculation: deposition of discs of culture media containing fungal structures and deposition of spore suspensions in needle-punctured lesions. The fungal species used were Fusarium falciforme, F. sulawesiense, F. pernambucanum, F. kalimantanense, and Fusarium sp. Fruits of two hybrids from four types of melons, canary (Goldex and Gold Mine), piel de sapo (Grand Prix and Flecha Verde), galia (McLaren and DRG3228), and cantaloupe (SV1044MF and Bonsai), were used. Disease severity was assessed by measuring the lesions, disease severity index, fruit firmness, and degrees Brix of fruits. The five Fusarium species caused rot in the fruits of all melon hybrids studied and the aggressivity of those fungal species varied with the type and hybrid. Fruits of the hybrids McLaren and Bonsai presented the largest lesions among all melon hybrids, and hybrids of canary type (Gold Mine and Goldex) were the most tolerant to rot caused by the Fusarium species investigated. Furthermore, the greater the severity of Fusarium fruit rot, the lower the pulp firmness of the fruits, but degrees Brix did not correlate with the onset of the disease.

Growth behavior of low populations of Listeria monocytogenes on fresh-cut mango, melon and papaya under different storage temperatures.

The growth behavior of Listeria monocytogenes low population (1-4 cells/sample) on fresh-cut mango, melon, papaya and fruit mix stored at 4, 8, 12 and 16 °C was evaluated over 10 days. Mango showed the lowest counts for L. monocytogenes during 10 days regardless of storage temperature (<1.7 log cfu.g-1). Melon supported high bacterial growth over 10 days, reaching 5 log cfu.g-1 at 16 °C. Both the fruit and storage temperature influenced the Listeria low population growth potential (δ). Cumulative frequency distribution of L. monocytogenes showed that after 10 days, 100% of fresh-cut fruits and fruit mix stored at 4 °C remained ≤2 log cfu.g-1, while at 12 and 16 °C 100% of melon, papaya and fruit mix samples exceeded this limit. At 8 °C, 100% of mango and fruit mix samples remained below this limit after 10 days, whereas 100% of melon and papaya reached it after 7 days. Results indicate 4 °C as the ideal to store safely fresh-cut mango, melon, papaya and fruit mix for 10 days. Besides, 8 °C can also be an option, but not for melon and papaya. Findings highlight the ability of L. monocytogenes to survive and grow in fresh-cut fruits even at a very low initial population levels.

Effect of pulsed light on postharvest disease control-related metabolomic variation in melon (Cucumis melo) artificially inoculated with Fusarium pallidoroseum.

Pulsed light, as a postharvest technology, is an alternative to traditional fungicides, and can be used on a wide variety of fruit and vegetables for sanitization or pathogen control. In addition to these applications, other effects also are detected in vegetal cells, including changes in metabolism and secondary metabolite production, which directly affect disease control response mechanisms. This study aimed to evaluate pulsed ultraviolet light in controlling postharvest rot, caused by Fusarium pallidoroseum in 'Spanish' melon, in natura, and its implications in disease control as a function of metabolomic variation to fungicidal or fungistatic effects. The dose of pulsed light (PL) that inhibited F. pallidoroseum growth in melons (Cucumis melo var. Spanish) was 9 KJ m-2. Ultra-performance liquid chromatography (UPLC) coupled to a quadrupole-time-of-flight (QTOF) mass analyzer identified 12 compounds based on tandem mass spectrometry (MS/MS) fragmentation patterns. Chemometric analysis by Principal Components Analysis (PCA) and Orthogonal Partial Least Squared Discriminant Analysis (OPLS-DA) and corresponding S-Plot were used to evaluate the changes in fruit metabolism. PL technology provided protection against postharvest disease in melons, directly inhibiting the growth of F. pallidoroseum through the upregulation of specific fruit biomarkers such as pipecolic acid (11), saponarin (7), and orientin (3), which acted as major markers for the defense system against pathogens. PL can thus be proposed as a postharvest technology to prevent chemical fungicides and may be applied to reduce the decay of melon quality during its export and storage.

Qualidade microbiológica de melões minimamente processados / Microbiological quality of minimally processed melons

O consumo de frutas minimamente processadas tem aumentado em função da sociedade moderna que procura hábitos de vida mais saudáveis. O objetivo desta pesquisa foi o de analisar a qualidade microbiológica de melões minimamente processados comercializados em hipermercados da cidade de João Pessoa, Paraíba. A pesquisa foi realizada com doze amostras de melões minimamente processados. As análises microbiológicas foram realizadas para coliformes termotolerantes (45° C) e Salmonella spp. sendo os resultados comparados com os padrões legais. Observou-se que a totalidade das amostras apresentaram valores <10 NMP/g para coliformes a 45º C e ausência de Salmonella spp. Estes resultados indicaram a eficiência das Boas Práticas de Fabricação (BPF) no controle de qualidade destes produtos.(AU)

Avaliação sensorial de doce light de maracujá com chuchu / Sensory evaluation of the sweet light of maracujá with chuchu

A necessidade da inovação em produtos funcionais vem tornando-se cada vez mais exigida com o passar dos anos, pois a preocupação com a qualidade de vida virou um marco da atualidade. Diante disso, o presente trabalho teve como objetivo desenvolver um doce ligth de maracujá com chuchu, avaliar suas características sensoriais, microbiológicas. Para a preparação empregou matéria prima oriunda do comércio local da cidade de Imperatriz ­ Maranhão, e elaborado no Laboratório de Análise Sensorial - UFMA. Produziu três formulações, F1, F2 e F3 tendo açúcar cristal, stevia e sucralose, respectivamente. Posteriormente, as amostras foram submetidas as análises microbiológicas e análise sensorial. As análises foram aceitáveis em seus parâmetros microbiológicos e sensoriais.

Qualidade microbiológica de melões minimamente processados / Microbiological quality of minimally processed melons

O consumo de frutas minimamente processadas tem aumentado em função da sociedade moderna que procura hábitos de vida mais saudáveis. O objetivo desta pesquisa foi o de analisar a qualidade microbiológica de melões minimamente processados comercializados em hipermercados da cidade de João Pessoa, Paraíba. A pesquisa foi realizada com doze amostras de melões minimamente processados. As análises microbiológicas foram realizadas para coliformes termotolerantes (45° C) e Salmonella spp. sendo os resultados comparados com os padrões legais. Observou-se que a totalidade das amostras apresentaram valores <10 NMP/g para coliformes a 45º C e ausência de Salmonella spp. Estes resultados indicaram a eficiência das Boas Práticas de Fabricação (BPF) no controle de qualidade destes produtos.

Persistence of Bacteroidales and other fecal indicator bacteria on inanimated materials, melon and tomato at various storage conditions.

In order to determine the microbial safety of produce, conventional fecal indicator bacteria (CFIB) such as Escherichia coli and Enterococcus are quantified as a standard practice. Bacteroidales are also fecal indicators mostly used for water samples; however, their use and persistence in foods has been rarely studied. In this study, persistence of both CFIB and genetic markers of host-specific Bacteroidales was determined in artificially contaminated materials and vegetables with different textured surfaces under different storage conditions. Sterile feces were contaminated with E. coli, E. faecalis, Bacteroidesthetaiotaomicron (human origin), and Bacteroidales from porcine and bovine origin. Feces were applied to filters of mixed cellulose esters and tomatoes (smooth surface) and flat cork coupons and melons (rough surface) and stored at 10 °C/95% relative humidity (RH) and 25 °C/65%RH for up to 25 days. Bacteroidales markers were analyzed by real-time polymerase chain reaction (qPCR), whereas CFIB were plated onto selective agars. CFIB detection on filters and cork surfaces declined over time. E. coli decreased 2.9 log CFU and 1.2 log CFU per filter and cork, respectively, at 10 °C/95%RH and 5.8 log CFU and 1.8 log CFU per filter and cork, respectively, at 25 °C/65%RH. E. faecalis decreased 1.9 log CFU on filters and 1.3 log CFU on cork at 10 °C/95%RH and 2.6 log CFU/filter and cork under both storage conditions. Although E. coli levels in tomatoes slightly increased during storage, the levels decreased by the end of the assays. However, CFIB levels in melons stored at 10 °C/95%RH increased after 20 days; when stored at 25 °C/65%RH, these levels increased after five days. Bacteroidales levels (universal and host-specific markers) in inanimated material and produce did not show significant differences (P ≤ 0.01) over time. Stability and persistence of Bacteroidales genetic markers make them superior to CFIB as markers and are alternatives for determining the risk of exposure to feces-contaminated produce.

Chemometric evaluation of the volatile profile of probiotic melon and probiotic cashew juice.

The aim of this study was to evaluate the influence of the lactic acid fermentation on volatile compounds of melon and cashew apple juices. The effect of the fermentation processing on the volatile profile of probiotic juices was assessed by HS-SPME/GC-MS coupled to chemometrics with 67.9% and 81.0% of the variance in the first principal component for melon and cashew juices, respectively. The Lactobacillus casei fermentation imparted a reduction of ethyl butanoate, ethyl-2-methylbutirate, and ethyl hexanoate for melon juice; and of ethyl acetate, ethyl-2-methyl butanoate, ethyl crotonate, ethyl isovalerate, benzaldehyde, and ethyl hexanoate for cashew juice. Measurements of the stability of these compounds and the formation of the component 3-methyl-2-butenyl in melon juice may be used as a volatile marker to follow the juice fermentation. These findings suggested that even though it is not a dairy product the lactic acid fermentation of fruits developed a volatile profile combining the fruit and lactic acid fermentation volatiles with mildly formation or degradation of aroma compounds.

Cloning and expression of class I chitinases in Hami melon after Penicillium infection.

Chitinases are important disease-related proteins that play critical roles in plant defense against disease. To investigate the function of chitinases in the resistance of Hami melon to Penicillium infection, the gene encoding chitinases, HmCHT-2, was cloned and RT-PCR was used to measure expression levels of HmCHT-2. When the Hami melon was infected by Penicillium sp after 0, 12, 36, 48, 60, and 72 h. The results showed that comparing to the control group, the time of expression levels reaching to the peak delayed and the expression levels maintained at a significantly high level for a longer time. These results suggest that HmCHT-2 may contribute to the defense of Hami melon against fungal infection.

Strains of the Group I Lineage of Acidovorax citrulli, the Causal Agent of Bacterial Fruit Blotch of Cucurbitaceous Crops, are Predominant in Brazil.

Bacterial fruit blotch (BFB), caused by the seedborne bacterium Acidovorax citrulli, is an economically important threat to cucurbitaceous crops worldwide. Since the first report of BFB in Brazil in 1990, outbreaks have occurred sporadically on watermelon and, more frequently, on melon, resulting in significant yield losses. At present, the genetic diversity and the population structure of A. citrulli strains in Brazil remain unclear. A collection of 74 A. citrulli strains isolated from naturally infected tissues of different cucurbit hosts in Brazil between 2000 and 2014 and 18 A. citrulli reference strains from other countries were compared by pulsed-field gel electrophoresis (PFGE), multilocus sequence analysis (MLSA) of housekeeping and virulence-associated genes, and pathogenicity tests on seedlings of different cucurbit species. The Brazilian population comprised predominantly group I strains (98%), regardless of the year of isolation, geographical region, or host. Whole-genome restriction digestion and PFGE analysis revealed that three unique and previously unreported A. citrulli haplotypes (assigned as haplotypes B22, B23, and B24) occurred in Brazil. The greatest diversity of A. citrulli (four haplotypes) was found among strains collected from the northeastern region of Brazil, which accounts for more than 90% of the country's melon production. MLSA clearly distinguished A. citrulli strains into two well-supported clades, in agreement with observations based on PFGE analysis. Five Brazilian A. citrulli strains, representing different group I haplotypes, were moderately aggressive on watermelon seedlings compared with four group II strains that were highly aggressive. In contrast, no significant differences in BFB severity were observed between group I and II A. citrulli strains on melon and squash seedlings. Finally, we observed a differential effect of temperature on in vitro growth of representative group I and II A. citrulli haplotypes. Specifically, of 18 group II strains tested, all grew at 40 and 41°C, whereas only 3 of 15 group I strains (haplotypes B8[P], B3[K], and B15) grew at 40°C. Three strains representing haplotype B8(P) were the only group I strains that grew at 41°C. These results contribute to a better understanding of the genetic diversity of A. citrulli associated with BFB outbreaks in Brazil, and reinforce the efficiency of MLSA and PFGE analysis for assessing population structure. This study also provides the first evidence to suggest that temperature might be a driver in the ecological adaptation of A. citrulli populations.

Cloning of superoxide dismutase from post-harvest Hami melon and quantitative expression analysis before and after disease.

Primers were designed according to the Cu/Zn-SOD gene sequences of cloned Cucurbits plants (cucumbers and watermelons) available in NCBI. Total RNA from Hami melon pulp was used as a template. Following RT-PCR amplification, a 403-bp fragment of the Hami melon Cu/Zn-SOD gene was obtained. According to alignment in BLAST and phylogenetic tree analysis, the cloned gene fragment was confirmed to be the Hami melon Cu/Zn-SOD gene sequence. Real-time fluorescence quantitative expression analysis indicated that there were differences in the expression of SOD mRNA expression before and after infection by blue mold. mRNA expression was maximal 24-h after infection, indicating that the product of the SOD gene plays an important role in the rotting and degeneration of Hami melons as a consequence of bacterial infection during the preservation period.

Diversity of Ralstonia solanacearum in French Guiana expands knowledge of the "emerging ecotype".

Although bacterial wilt remains a major plant disease throughout South America and the Caribbean, the diversity of prevalent Ralstonia solanacearum populations is largely unknown. The genetic and phenotypic diversity of R. solanacearum strains in French Guiana was assessed using diagnostic polymerase chain reactions and sequence-based (egl and mutS) genotyping on a 239-strain collection sampled on the families Solanaceae and Cucurbitaceae, revealing an unexpectedly high diversity. Strains were distributed within phylotypes I (46.9%), IIA (26.8%), and IIB (26.3%), with one new endoglucanase sequence type (egl ST) found within each group. Phylotype IIB strains consisted mostly (97%) of strains with the emerging ecotype (IIB/sequevar 4NPB). Host range of IIB/4NPB strains from French Guiana matched the original emerging reference strain from Martinique. They were virulent on cucumber; virulent and highly aggressive on tomato, including the resistant reference Hawaii 7996; and only controlled by eggplant SM6 and Surya accessions. The emerging ecotype IIB/4NPB is fully established in French Guiana in both cultivated fields and uncultivated forest, rendering the hypothesis of introduction via ornamental or banana cuttings unlikely. Thus, this ecotype may have originated from the Amazonian region and spread throughout the Caribbean region.

Electronic detection of Drechslera sp. fungi in charentais melon ( Cucumis melo Naudin) using carbon-nanostructure-based sensors.

The development of chemical sensor technology in recent years has stimulated an interest regarding the use of characteristic volatiles and odors as a rapid and early indication of deterioration in fruit quality. The fungal infestation by Drechslera sp. in melons is a severe problem, and we demonstrate that electronic sensors based on carbon nanostructures are able to detect the presence of these fungi in melon. The responses of sensor conductance G and capacitance C at 27 kHz were measured and used to calculate their ΔG and ΔC variation over the full melon ripening process under shelf conditions with proliferation of Drechslera sp. fungi. The sensor response showed that these fungi can be electronically identified in charentais melon, constituting an effective and cheap test procedure to differentiate between infected and uninfected melon.

A field study of the microbiological quality of fresh produce of domestic and Mexican origin.

Produce is responsible for an increasingly larger proportion of foodborne disease outbreaks. In particular, the globalization of the food supply may introduce new food safety risks and allow widespread distribution of contaminated food, particularly produce. The objectives of this study were to: (i) compare the overall quality of domestic and Mexican produce throughout the packing process; (ii) examine changes in microbiological quality of both domestic and Mexican produce at each stage of production and processing; and (iii) evaluate the prevalence of select pathogens on fresh produce, including leafy green, herbs, melons, and vegetables. Furthermore, we also sought to characterize the antibiotic resistance profiles of Enterococcus faecium and Enterococcus faecalis strains isolated from fresh produce. A total of 466 produce and matching environmental swab samples was collected from various locations in packing sheds in the southern US from November 2002 through December 2003. These samples were assayed by enumerative tests for total aerobic bacteria (APC), total coliforms, total Enterococcus, and E. coli. Produce samples were also analyzed for the presence of Salmonella, Listeria monocytogenes, Shigella, and E. coli O157:H7. A total of 112 E. faecium and E. faecalis isolates were further screened for antibiotic resistance using a panel of seventeen antibiotics. Overall, the microbiological quality of fresh produce ranged from 4.0 to 7.9 log(10) CFU/g (APC); less than 1.0 log(10) to 4.5 log(10) CFU/g (coliforms); less than 1.0 log(10) to 4.0 log(10) CFU/g (E. coli); and less than 1.0 log(10) to 5.4 log(10) CFU/g (Enterococcus). No Salmonella, Shigella, or E. coli O157:H7 were detected from the 466 25-g produce samples tested. However, three domestic cabbage samples were found to be positive for L. monocytogenes. Of the Enterococcus isolates, E. faecium had a higher degree of resistance to antibiotics in general, while Enterococcus spp. isolated from Mexican produce had a higher degree of antibiotic resistance when compared to strains isolated from produce samples of domestic origin. Despite increased attention to the role of imported produce in foodborne disease, this study does not support the assumption that domestic produce is of higher microbial quality than Mexican produce.