Grapeshield

An SO2 Pads for all kinds of grapes preservation

An SO2 Pads for all kinds of grapes preservation

SO₂ gas-generating pads are specialized packaging materials used in the post-harvest preservation of table grapes during storage and transport. These pads slowly release sulfur dioxide (SO₂) gas, which acts as an antifungal agent, primarily to prevent Botrytis cinerea, commonly known as gray mold, one of the major post-harvest diseases in grapes.

These pads contain a chemical mixture (usually sodium metabisulfite (Na₂S₂O₅)) that reacts with moisture in the storage environment to produce sulfur dioxide gas. The gas then diffuses around the grapes, inhibiting mold growth and extending shelf life.

Types of SO₂ Pads

There are different types based on the rate and duration of gas release:

  1. Slow-Release Pads
  • Release low levels of SO₂ over several weeks.
  • Ideal for long-term storage and shipping.
 

      2. Dual-Release Pads

  • Provide a burst of SO₂ initially(fast release) to kill existing mold spores.
  • Followed by a slower, sustained releaseto prevent further growth.
  • Commonly used in international shipping.
 

     3. Fast-Release Pads

  • Designed for short-term useand rapid fumigation.
  • Sometimes used immediately after harvest or before market.

Benefits of SO₂ Pads

Different benefits:

Prevent gray mold and stem browning

Extend shelf life by up to 3 months

Maintain berry firmness and appearance

Reduce post-harvest losses during export

Typical Uses

SO2 Pads are used in orchards and gardens for grapes such as:

How to Use SO₂-Generating Pads for Grapes

Pre-cool the grapes

Pre-cool the grapes to around 0 °C (32 °F) as quickly as possible after harvest. This reduces decay and rachis browning.

Line the packaging box

Line the packaging box (corrugated or plastic) with a plastic liner. Place a moisture-absorbing layer (like absorbent paper) at the bottom to protect against moisture-related damage.

Layering grapes and pad

Place grapes into the lined box.

Lay the SO₂ pad on top, with the printed (non-chemical) side facing upward/towards grapes. Tissue may be used between grapes and the pad for sensitive varieties.

Activate the pad

Moisture-activated pads (e.g., KIF pads) can be sprayed or sprinkled with water to trigger immediate SO₂ release followed by sustained emission.

Seal the box

Seal the box completely and store in a cold storage environment (0–1 °C, RH ~92–95%). Use perforated liners for better SO₂ circulation and to minimize weight loss.

Post-storage handling

Label boxes clearly as containing SO₂ pads. Open in a well-ventilated area. People with sulfite sensitivity or asthma should avoid handling these pads.

Benefits for Farmers & Gardeners

Looking for Reliable Fruit Protection Solutions?

Partner with Torrenza Chemtech Industries to improve fruit quality, reduce waste, and grow sustainably.