Table of Content

Chapter 1: OVERVIEW OF MILK

1. The chemistry of milk

2.1. Bacteria in milk

2.2. Infection at the farm

3. Microorganism in milk

3.1. Procaryote

3.2. Eucaryote

Yeasts

Moulds

Bacteriophages

Chapter 2: CARBON DIOXIDE ANTIMICROBIAL MECHANISM AND FACTORS THAT INFLUENCE EFFICIENCY

1. CO2 purification

1.1. Sources of CO2

1.2. CO Purification

2. Mechanism of carbon dioxide antimicrobial action

2.1. General

2.2. Detailed mechanism

2.2.1. Step 1: solubilization of pressurized CO2 in the external liquid phase

2.2.2. Step 2: cell membrane modification

2.2.3. Step 3: intracellular pH decrease

2.2.4. Step 4: key enzyme inactivation/cellular metabolism inhibition due to pHi lowering

2.2.5. Step 5: direct (inhibitory) effect of molecular CO and HCO − on metabolism

2.2.6. Step 6: disordering of the intracellular electrolyte balance

2.2.7 Step 7: removal of vital constituents from cells and cell membranes

3. Factors that influence efficiency of carbon dioxide antimicrobial action

3.1. Effect of pressure and temperature

3.2. Effect of the physical state of CO2

3.3. Effect of agitation

3.4. Effect of water content

3.5. Effect of depressurization rate

3.6. Susceptibility of different microorganisms

3.7. Effect of the initial bacterial concentration on the efficacy of HPCD

3.8. Effect of the physical and chemical properties of the suspending medium

3.9. Effect of initial environmental pH of suspending medium

3.10. Effect of culturing conditions and stage of cell growth

3.11. Metabolically injured organisms

3.12. Effect of combination treatments

3.13. Occurrence of HPCD-resistant mutants

4. Characterization of microbial survival curves during HPCD treatments

5. Applications of CO2 addition raw milk

5.1. Storage and transport

Chapter 3: METHOD FOR PASTEURIZE MILK BY USING CARBON DIOXIDE

1. Technological processing

1.1. Centrifugation and standardisation

1.2. Deaeration

1.3. Homogenisation

1.4. Pasteurisation

1.5. Filling and package

1.6. Preservation

2. Quality target of treated products

3. Important opportunities and drawbacks of using high pressure carbon

dioxide (HPCD) to pasteurize milk as compared to other methods

References

70 pages

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Supervisor: As.Pro. Le Van Viet Man

Students:

Ho Chi Minh City University of Technology

Faculty of Chemical Engineering