Green


GREEN

What is Uvasys Green?

Uvasys is the pioneer & industry leading brand of laminated plastic SO2  generating sheets, used worldwide where Table Grapes are produced, stored or exported.

Uvasys Green is, the original, true dual release SO2  generating sheet, protecting grapes from postharvest fungal decay, particularly Botrytis cinerea

This signature version has both a Fast Release and a Slow Release layer and can be used directly on the grapes. 

 

    How does it work?

    Click to enlarge.
    • Uvasys Green consists of a sequence of laminated plastic membranes, each bonded by a wax layer containing precise concentrations, and particle sizes, of Sodium Metabisulfite: Na2S2O5.
    • The top and middle plastic membranes, sandwiches the Slow Release layer.
    • The middle and bottom membranes sandwiches the Fast Release layer.
    • At above 75% relative humidity an autocatalytic reaction is initiated, whereby the sheet starts releasing a time, and concentration-varying stream of SO2.
    • The Fast Release sterilizes the surface of the table grapes, by releasing a large enough dose of sulphur dioxide over a 24 to 48 hour period to kill and eliminate any actively growing Botrytis cinerea fungal spores.
    • The Slow Release layer remains active for up to 120 days, emitting a low, continual dose of sulphur dioxide gas, concentrated enough to inhibit any superficial latent or inherent Botrytis cinerea spores from growing, but also low enough to ensure sulfite residues within the table grapes remain safely below the legal limit of 10 ppm. Infection which occurred at flowering could still develop but will be contained to the affected berry.
    • The quantity of SO2 emitted is critical to the efficacy of the product as an excessive release of SO2 can cause bleaching while insufficient release may not prevent the development of Botrytis.
    • SO2 not only protects against fungal growths but also helps in maintaining a greener stem colour.
    • For more detail on the chemical reactions please visit the Research page.

    Instructions

    STEP 1

    Use the Uvasys sheet recommended for the corresponding carton size; refer to the below options table.

    STEP 2

    Line the carton with a perforated (ventilated) liner bag. The optimum ventilation type and size will depend on your unique combination of: Production area; Cooling systems; Post-harvest handling times; Pack type (loose, punnets, carry bag, etc.)

    STEP 3

    Fold open the liner bag once correctly positioned inside the carton. Please note: Uvasys needs a minimum of 75% Relative Humidity to activate and using a liner bag will also limit moisture loss.

    STEP 4

    Place grapes inside the liner bag. Punnets (heat sealed or open top), clamshells, Zip-lock bags, polycote bags, carry bags or loose packed grapes may be used.

    NB: When using open top punnets please ensure a minimum of 10 mm headroom. If this is not achievable, please use tissue paper (25g or higher) beneath the Uvasys sheet or make use of side-ventilated punnets.

    STEP 5

    Place the Uvasys sheet on top of the grapes, with the printed (shiny) side facing away from the grapes. (We recommend not to cut or modify the sheet)

    Use a MAM on top of the Uvasys sheet if you are expecting excessive condensation.

    STEP 6

    Fold the plastic liner, back, over the content of the carton, close and cool to storage temperature (-0.5 ℃) as soon as possible.

    Specifications

    Please click on the download button for a PDF of the Material Safety Data Sheet (MSDS). You will be taken to the Downloads section of the website where a login is required to retrieve the document. A suitable PDF reader will be required. Please use the Contact Us page for specific questions.

    Options

    Please find below the generic sizes pertaining to the product. We also manufacture alternative sizes depending on specific client requests. Please get in touch to find out if we already have the size you require available.

    CARTON SIZE(mm) SHEET SIZE(mm) PACK SIZE (units)
    400 x 300 356 x 260 1000
    500 x 300 460 x 260 500
    500 x 400 460 x 350 500
    600 x 400 530 x 350 500

    FAQ

    For frequently asked questions pertaining to this product please click this link where you will be taken through to the FAQ page.

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    Disclaimer: This website is for marketing purposes only. All references to values, volumes, timeframes and other variables are guidelines only. If you require precise information please use the contact us page with your query.

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