Milk Processing: Pasteurization

Milk Processing

• Definition: Pasteurization is a process that involves heating milk to a high temperature to kill bacteria and extend its shelf life.
• Temperature and Time: Milk is heated to a minimum of 161°F (72°C) for at least 15 seconds, or to 145°F (63°C) for at least 30 minutes.
• Types of Pasteurization:
  • Vat Pasteurization: Milk is heated in a batch process, often used for small-scale or specialty dairy products.
  • Continuous Pasteurization: Milk is heated continuously as it flows through a heat exchanger, commonly used in large-scale dairy operations.
• Effects on Milk:
  • Kills bacteria, including pathogens like E. coli and Salmonella
  • Inactivates enzymes that can cause spoilage
  • Extends shelf life by reducing microbial growth

Food Safety

• Importance: Pasteurization is crucial for ensuring food safety, as it eliminates pathogens that can cause foodborne illnesses.
• Regulations: Pasteurization is mandated by law in many countries, including the United States, to ensure the safety of milk and dairy products.
• Pathogens Eliminated: Pasteurization kills bacteria, viruses, and fungi that can cause foodborne illnesses, including:
  • E. coli
  • Salmonella
  • Listeria
  • Campylobacter
  • Brucella
• Benefits: Pasteurization protects consumers, especially vulnerable populations like the elderly, pregnant women, and young children, from serious illnesses.

Milk Processing

• Pasteurization is a heat-treatment process that kills bacteria and extends milk's shelf life.
• Milk is heated to a minimum of 161°F (72°C) for at least 15 seconds or to 145°F (63°C) for at least 30 minutes.
• There are two types of pasteurization:
  • Vat pasteurization: a batch process used for small-scale or specialty dairy products.
  • Continuous pasteurization: a continuous process used in large-scale dairy operations.
• Pasteurization has several effects on milk:
  • Kills bacteria, including pathogens like E. coli and Salmonella.
  • Inactivates enzymes that can cause spoilage.
  • Extends shelf life by reducing microbial growth.

Food Safety

• Pasteurization is crucial for ensuring food safety and eliminating pathogens that can cause foodborne illnesses.
• Pasteurization is mandated by law in many countries, including the United States.
• The process kills bacteria, viruses, and fungi that can cause foodborne illnesses, including:
  • E. coli.
  • Salmonella.
  • Listeria.
  • Campylobacter.
  • Brucella.
• Pasteurization protects consumers, especially vulnerable populations like the elderly, pregnant women, and young children, from serious illnesses.

Heat Treatment

• Heat treatment aims to eliminate pathogenic microorganisms and extend shelf life of food products.
• The process involves heating the product to a temperature that kills most bacteria and other microorganisms, but not high enough to cause significant changes to the product's composition or nutritional value.

Types of Heat Treatment

• Low-temperature long-time (LTLT) pasteurization: 63°C for 30 minutes
• High-temperature short-time (HTST) pasteurization: 72°C for 15 seconds
• Ultra-high temperature (UHT) pasteurization: 135°C for 1-2 seconds

Dairy Products

• Pasteurization is widely used in the dairy industry to ensure the safety of milk and dairy products.
• The process involves heating the milk to a temperature that kills bacteria such as Salmonella, E.coli, and Listeria.
• Pasteurized dairy products include milk, cheese, yogurt, and ice cream.

Food Safety

• Pasteurization reduces the risk of foodborne illnesses by eliminating pathogens that can cause diseases such as tuberculosis, brucellosis, and listeriosis.
• Pasteurization is especially important for products that are consumed raw or undercooked, such as milk, juice, and eggs.

Microbial Inactivation

• Pasteurization is effective against a wide range of microorganisms, including bacteria (e.g. E.coli, Salmonella, Listeria), viruses (e.g. HIV, hepatitis), and fungi (e.g. mold, yeast).
• The heat treatment process denatures proteins and disrupts cell membranes, leading to microbial inactivation.
• The effectiveness of pasteurization depends on factors such as temperature, time, and the type of microorganism.

Sterilization

• Sterilization is a more extreme form of heat treatment that aims to eliminate all microorganisms, including spores.
• Sterilization is typically used for products that require a higher level of safety, such as medical equipment, pharmaceuticals, and food products for immunocompromised individuals.
• The process involves heating the product to a temperature of at least 121°C for 15 minutes.