Optimum Thermal Processing for Extended Shelf-Life (ESL) Milk.

Area of Science:

• Food Science
• Microbiology
• Dairy Technology

Background:

• Extended shelf-life (ESL) milk production involves thermal processing between HTST and UHT methods.
• ESL milk requires a refrigerated shelf-life exceeding 30 days.
• Balancing bacteriological quality, safety, and organoleptic properties is crucial for ESL milk.

Purpose of the Study:

• To inactivate vegetative bacteria and psychrotrophic bacterial spores, particularly *Bacillus cereus*.
• To minimize chemical changes, specifically β-lactoglobulin (β-Lg) denaturation, which causes cooked flavor.
• To establish optimal thermal processing parameters for ESL milk production.

Main Methods:

• Intense thermal processing, focusing on high temperature and short holding times.
• Direct heating methods and aseptic packaging are employed.
• Monitoring bactericidal effect (B*) and β-Lg denaturation levels.

Main Results:

• The study proposes specific targets for thermal processing: B* > 0.3 and ≤50% β-Lg denaturation.
• High temperature, short-time direct heating is identified as optimal.
• Aseptic packaging is essential for maintaining product quality.

Conclusions:

• Optimal thermal processing for ESL milk involves achieving a B* > 0.3 and ≤50% β-Lg denaturation.
• Direct heating and aseptic packaging are key to producing high-quality ESL milk.
• This approach ensures bacteriological safety and desirable sensory attributes.