PASTEURIZATION

1. Purpose

Pasteurization is the process of heating beverages to a specific temperature for a defined time to destroy harmful microorganisms, inactivate spoilage enzymes, and extend shelf life — without significantly altering flavor, color, or nutritional value.

2. Common Pasteurization Methods for Beverages

A. Tunnel Pasteurization (Post-Packaging)

• Process: Filled and sealed bottles/cans pass through a tunnel with progressively hotter water sprays, then cooled.

• Typical Parameters:

  • 60–70 °C for 10–20 minutes (depending on beverage pH and product type)

  • Measured in Pasteurization Units (PU): 1 PU = holding at 60 °C for 1 minute

• Applications: Beer, soft drinks, juices, ready-to-drink teas, energy drinks in cans/glass bottles

• Advantages: Pasteurizes the sealed package → no recontamination risk

• Considerations: Slower process, requires robust packaging that can withstand heat and pressure

B. Hot-Fill Pasteurization (In-Process)

• Process: Beverage is heated before filling, then filled hot into bottles (typically PET or glass) and sealed; the hot liquid sterilizes the container’s interior.

• Typical Parameters:

  • 85–95 °C for 15–30 seconds for acidic beverages (pH < 4.6)

• Applications: Juices, sports drinks, teas

• Advantages: Simpler equipment than tunnel pasteurization; effective for high-acid drinks

• Considerations: Not suitable for low-acid beverages without additional processing; PET bottles must be heat-resistant (“hot-fill PET”)

C. Flash Pasteurization (High-Temperature Short-Time, HTST)

• Process: Beverage is rapidly heated in a heat exchanger, held briefly, then cooled immediately before filling in an aseptic environment.

• Typical Parameters:

  • 71–75 °C for 15–30 seconds for acidic beverages

  • 125–135 °C for 2–10 seconds for low-acid UHT products

• Applications: Milk, fresh juices, cold-brew coffee, functional drinks

• Advantages: Minimal flavor and nutrient loss; high throughput

• Considerations: Requires aseptic filling to avoid recontamination

3. Factors Influencing Pasteurization Parameters

• pH of Beverage

  • High Acid (pH < 4.6) – Easier to pasteurize; kills pathogens like yeast and mold

  • Low Acid (pH ≥ 4.6) – Requires higher temperatures or pressure (risk of Clostridium botulinum)

• Beverage Type

  • Carbonated beverages generally need gentler heating to preserve CO₂

• Shelf-Life Target

  • Longer shelf life → higher total PU or temperature-time combination

• Packaging Type

  • PET, glass, aluminum must withstand heat without deformation or coating damage

4. Quality Considerations

• Over-Pasteurization Risks

  • Flavor degradation (cooked taste), color changes, vitamin loss

• Under-Pasteurization Risks

  • Microbial spoilage, food safety hazards

• Monitoring

  • Continuous temperature and time recording

  • Regular calibration of thermometers and timers

5. Record-Keeping

• Batch pasteurization log (time, temperature, PU, product, batch number)

• Maintenance and calibration records of pasteurization equipment

• Microbiological testing before and after processing