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There are many methods to test the efficiency of antimicrobial compounds. Our goals were to perform screens of several natural, experimental compounds and evaluate their effects on postharvest pathogenic fungi isolated from fruit. This screen was the first test in series that would allow us to see if these experimental compounds had potential use as components in a coating or as a preharvest treatment to help insure postharvest fruit quality. The disc assay method was chosen as a preliminary method for our screen as most of our compounds are water soluble and this method is straightforward, efficient and easy to interpret. This poster describes the testing of natural compounds against problematic postharvest fungi using the disc assay as a screening method. The results of various compounds are shown via the formation of a prominent zone of inhibition. Comparisons are also shown of non-responsive compounds to Penicillium digitatum and Geotrichum citri-aurantii. The clarity of using this method for step-wise dilutions of the anti-fungal compounds is shown.

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Organic foods are produced using agricultural practices that emphasize renewable resources and conservation of soil and water. Horticultural crops are grown and processed without synthetic fertilizers, pesticides, ingredients and processing aids. Crops or ingredients derived from genetic engineering, and use of ionizing radiation are prohibited in organic production. The challenge is to deliver produce that has the same safety, quality and shelf life as conventional products, with a limited array of tools available for sanitation and postharvest treatments. Organic operators, professionals servicing the industry, as well as researchers involved in organic production practices, should be aware of all the points in the process of storing, handling and transforming horticultural crops where accidental contamination could occur, and thus compromise organic integrity. This presentation summarizes the major points of the National Organic Program for processing and handling, and gives suggestions for postharvest research. For example, finding organic alternatives for postharvest decay control is critical to maintain food safety. Additionally, ingredients compatible for fresh cut and produce coatings must be developed for the organic market for food safety and competitiveness.

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`Gala' is an early season apple variety that has a distinctive aroma and flavor. Studies were conducted to identify volatile compounds that contribute to `Gala' aroma. `Gala' apples were harvested at optimum maturity in a commercial orchard. Volatile compounds were trapped on activated charcoal using dynamic headspace sampling and eluted with carbon disulfide. Odor profiles of the samples were determined using OSME, a method developed at Oregon State Univ. that combines gas chromatography and olfactometry with a time-intensity scale. Three trained panelists described odor characteristics of compounds eluted through a sniff port of a gas chromatograph. Compounds were identified by matching Kovats indices with those of standards and also by mass spectrometry. Butyl acetate, 2-methyl butyl acetate, and pentyl acetate were characteristic of `Gala' apple. Methyl-2-methyl butyrate, ethyl-2-methyl butyrate, pentyl acetate, and butyl-2-methyl butyrate carried apple-like descriptors.

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`Gala' is an early maturing apple variety that has a distinctive aroma and flavor. Its storage season is short and flavor volatile production is reduced following controlled atmosphere (CA) storage. The aroma and flavor characters of `Gala' apples were identified by 10 trained panelists. A vocabulary of 13 descriptors for the aroma of whole and cut fruit and 16 descriptors for flavor were used to characterize the changes of apples stored in CA and/or regular atmosphere (RA) during five months. When compared to RA storage, intensity of fruity (pear, banana and strawberry) and floral characters decreased after 2.5 months in CA for whole and cut fruit aroma and flavor. During the entire storage period under CA, aroma of cut apples retained high vegetative and citrus characters but had a less intense anise aroma. Sourness, starchiness and astringency were significantly higher, however, sweetness was significantly lower. A musty note was perceived in whole apples stored in CA for 5 months. Differences in fruitiness of whole fruit and sourness only were found between fruit stored for 4 months in CA followed by 1 month in RA and fruit stored 5 months in CA. Relationships between panel ratings of specific characters and corresponding quantitative analysis will be discussed.

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Strawberry is an important fruit crop in Florida. Yearly losses can be attributed to pre- and postharvest decay incited by Botrytis cinerea P. Micheli ex Pers. and postharvest decay resulting from primarily Rhizopus stolonifer (Ehrenb. ex Fr.) Vuillemin. In this study, the sanitizer peroxyacetic acid (100 μL·L−1) was sprayed on flowers and developing strawberries 1, 2, and 3 d preharvest. Most of the time, fruit sprayed 3 days before harvest had significantly less decay than fruit sprayed 1 day preharvest or not sprayed when stored at 18 °C. Strawberries sprayed in the field with peroxyacetic acid and then coated postharvest with 1% chitosan coating had reduced decay compared with fruit only treated preharvest with peroxyacetic acid (PAA) for up to 12 days in storage. Sensitivity of B. cinerea hyphae and conidia to PAA was shown by the presence of a zone of inhibition using the disc assay method.

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`Gala' apples were harvested at weekly intervals for 6 weeks, refrigerated at 0C, and evaluated by a consumer panel monthly over a 6 month period for overall liking, firmness, sweetness, tartness and flavor intensities. Firmness, titratable acidity and soluble solids concentration were also measured. Initial analysis of sensory data revealed multicollinearity for overall liking, sweetness, and flavor. The five descriptors explained 75 % of the dataset variation in the first two factors. An orthogonal rotation separated overall liking, flavor and sweetness, and firmness and tartness into two independent factors. The distribution of mean scores along these independent factors showed that panelists could perceive changes due to ripening and maturation. The multivariate factor analysis was better than univariate ANOVA at illustrating how apple maturity stages were apparent to untrained panelists. Firmness was the only instrumental variable correlated to firmness ratings in the sensory tests. None of the analytical measurements could explain overall liking.

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Oranges can be satisfactorily processed for fresh slices using a process of enzyme infiltration under vacuum. Scored ‘Valencia’ and ‘Hamlin’ oranges were placed under 90 kPa vacuum in water, 1% citric acid (CA), or 1000 ppm pectinase (Ultrazym) at 30 °C for 2 min followed by 30 min incubation in air. After peeling, fruit were washed, cut, and all but CA-infused slices were dipped in water or 1% CA for 2 min. Drained slices were placed in sealed 454-mL deli containers and stored at 5 °C for up to 21 days. All ‘Valencia’ slices had microbial counts less than 1.0 log cfu·g−1 (cfu = colony-forming units) after 7 days storage, and slices from CA-infused fruit had less than 1.0 log cfu·g−1 after 21 days storage. For ‘Hamlin’, CA dips controlled bacterial growth on slices from water-infused oranges, except at 14 days. Enzyme-infused oranges resulted in slices with lower counts for both cultivars. CA-treated sliced (post enzyme treatment or by infusion) oranges had higher titratable acidity initially (‘Hamlin’) and after 14 days (‘Valencia’). When presented to a taste panel, ‘Valencia’ slices from enzyme-peeled fruit were preferred for texture after 2 days and 8 days in storage. In contrast, slices from fruit infused with water or citric acid were least preferred, were firmer, and had thicker segment membranes. Appearance of enzyme-treated fruit was preferred for ‘Hamlin’ oranges. Enzyme treatments increased levels of aroma volatiles, methanol and methyl butanoate, in ‘Hamlin’ slices, but overall sensory flavor data were unaffected.

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