Hot Water Treatment (HWT) is one of the most essential pre-storage processes for fresh fruits before entering the CASS – Controlled Atmosphere Storage System.
This treatment minimizes microbial risks, improves fruit surface quality, and enhances long-term preservation outcomes, enabling year-round sales and reduced post-harvest losses.
1. What is Hot Water Treatment (HWT)?
HWT is a non-chemical method in which fruits are immersed or bathed in heated water (typically 48–53°C for 2–5 minutes, depending on the fruit type).
Its primary functions include:
- Inhibiting post-harvest fungal infection
- Reducing insect and pest populations
- Cleaning and stabilizing the fruit epidermis
- Reducing moisture loss
- Extending shelf life and preservation time
In many export markets (Japan, EU, Australia), HWT is a mandatory phytosanitary step.
2. Why is HWT essential before storing fruits in CASS?
CASS works by reducing respiration rate, adjusting atmospheric composition, and slowing microbial growth within the storage chamber.
However:
If fruits enter the CASS system carrying fungi, spores, or insects, risks of cross-contamination remain significant.
Therefore, HWT acts as the “frontline cleaning process”, ensuring the incoming produce is safe, uniform, and stable before long-term CA storage.
3. Scientific Mechanisms: How HWT Enhances Storage Performance
3.1. Heat inactivation of microorganisms
Temperatures of 48–53°C can denature proteins and disrupt:
- Fungal spores (e.g., Colletotrichum, Botrytis, Alternaria)
- Bacteria causing soft rot
- Eggs and larvae of pests
This leads to significantly lower pathogen loads.
3.2. Stabilization of the fruit epidermis
HWT helps:
- Clean microbial and dust contaminants
- Restore the natural wax layer
- Seal micro-injuries on the skin
Resulting in reduced moisture loss, better firmness, and lower shriveling during storage.
3.3. Reduction of internal ethylene production
Heat reduces the activity of ACC oxidase and other ethylene-related enzymes, leading to:
- Slower ripening
- Longer shelf life
- More synchronized fruit quality
Once combined with CASS, the reduction in ethylene activity is significantly amplified.
3.4. Improved uniformity across lots
Fruits treated with HWT show:
- More stable respiration
- Reduced fungal contamination
- Higher consistency in post-harvest behavior
This is essential for long-term CA storage (30–90 days or more).
4. Economic Impact: How HWT Reduces Post-Harvest Losses
Typical losses in Vietnam’s post-harvest supply chain:
- 10–30% before entering storage
- 20–40% during conventional storage
HWT significantly reduces:
- Surface mold
- Stem-end rot
- Chilling injury sensitivity
- Weight loss
Studies and practical data suggest:
🔹 60–90% reduction in fungal risk
🔹 15–25% reduction in weight loss
🔹 20–40% increase in Grade-A fruit ratio
When paired with CASS, storage duration can extend 3–5 times longer, enabling:
- Planned sales
- Price optimization
- Long-distance export stability
5. At CASS: HWT is a Standardized, Technically Optimized Process
CASS implements HWT using standardized international protocols:
5.1. Automated temperature control
- ±0.2°C accuracy
- Customized to each fruit variety
- Prevents heat damage or uneven heating
5.2. Continuous water circulation
Ensures uniform thermal distribution.
5.3. Optimized exposure time
Based on empirical trials for each crop.
5.4. Integrated air sterilization system in CASS
Prevents recontamination after HWT.
5.5. SOP-based post-harvest workflow
Ensures:
- No peel scalding
- No stem browning
- No excessive softening
6. Direct Benefits for Businesses Using HWT at CASS
✔ Lower risk before storage
✔ Higher quality input for CA preservation
✔ Better export-grade consistency
✔ Reduced losses – Increased profitability
✔ Strong synergy with CA technology
HWT is essentially the “cleaning and stabilization phase” required before fruits can successfully endure long-term controlled atmosphere storage.
Conclusion: HWT Is the Foundation of Successful High-End Preservation
In modern post-harvest management, HWT is not optional—it is fundamental.
No proper HWT → no stable CA storage.
No stable CA storage → no long-term sales advantage.
HWT + CASS is the combination that enables producers and exporters to achieve premium-grade preservation, improve logistics efficiency, reduce losses, and compete in high-value export markets
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CÔNG TY TNHH BẢO QUẢN RAU QUẢ CASS
- Hotline/Zalo: 0931790829 – 0931780829
- Email: cass@cass.vn
- Website: cass.vn
- Fanpage: CASS – Kho bảo quản nông sản tươi bằng công nghệ CA
- Địa chỉ kho (trước sáp nhập): Lô F5, Đường số 6, KCN Hoà Bình, Huyện Thủ Thừa, Tỉnh Long An
- Địa chỉ kho (sau sáp nhập): Lô F5, Đường số 6, KCN Hoà Bình, Xã Thủ Thừa, Tỉnh Tây Ninh
