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Introduction to food processing
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Importance of Food Drying - Extraction of moisture by sun, air, heat or vacuum to inhibit the growth of molds, bacteria and yeasts

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Importance of Food Drying

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Introduction to food processing

Introduction to Food Processing

Axtel India

Why process foods

Why process foods?

  • Extend edible time frame -Preservation

  • Make better tasting foods

  • Make more varieties of food

  • Convenience



  • Extraction of moisture by sun, air, heat or vacuum to inhibit the growth of molds, bacteria and yeasts

    • Name 3 dried foods



  • The addition of salt or a brine solution to foods to decrease the activity of molds, bacteria and yeasts.

    • Name 3 salted foods



  • The addition of a chemical compound (sodium nitrate or sodium nitrite) to food to slow the growth of bacteria.

    • Name 3 cured foods



  • The use of special bacteria, molds or yeasts to prevent spoilage by converting the elements of food that spoil easily to stable elements that act as preservatives.

    • Name 3 fermented foods

Freeze drying

Freeze Drying

  • The freezing of food and the subsequent removal of water from the frozen food through the use of heat and a vacuum.



  • The addition of smoke and heat to preserve food by the action of the chemicals from the smoked wood and the partial drying of the food.

    • Name 3 smoked foods

Canning aseptic packaging

Canning/Aseptic Packaging

  • The packing of food in a container, sealing the container and heating it to sterilize the food.

    • Name 3 canned foods



  • The heating of milk and other liquids which reduces the number of disease-producing bacteria.

    • Name 3 pasteurized foods



  • The lowering of the temperature of food to inhibit the growth of bacteria, molds and yeasts.

    • Name 3 refrigerated foods



  • The lowering of the temperature of food to temperatures below 28 degrees F to stop the growth of bacteria, yeasts and molds and to kill parasites.

    • Name 3 frozen foods

Food concentration

Food concentration

  • Heating food until it boils and removing the water or partially freezing food and removing water in the form of ice crystals.

    • Name 3 concentrated foods



  • Passing energy through food to destroy insects, fungi, or bacteria that cause human disease or cause food to spoil.

    • Name 3 irradiated foods

Food safety

Food Safety

  • HAACP: Hazard Analysis Critical Control Point

  • What safety risk is present for each food

    • Pathogenic microorganisms

      • Bacteria, viruses

    • Spoilage microorganisms

      • Fungi, bacteria

  • What foods are at greatest risk for contamination?

Most important qualities to control

Most important qualities to control

  • pH

    • Bacteria thrive in a pH neutral environment (7)

    • Items with pH above 8 tend to be very bitter & toxic

    • Foods with pHs below 6 tend to be tart or sour

      1 7 14



Qualities to control

Qualities to control

  • Temperature

  • 40 – 140°F = the temperature danger zone

    • Rapid multiplication of microorganisms

  • <40°F very slow growth

  • <28°F – no growth – no death

  • >140°F – death of microorgamisms

Qualities to control1

Qualities to Control

  • Moisture content & Protein content

  • Bacteria need a high moisture content

  • Fungi can grow in lower moisture

    • Dry foods won’t make you sick

    • Dry foods do spoil

  • Bacteria need protein, fungi less so

    • Candy & carbohydrates may spoil but don’t won’t make you sick

Food deterioration

Food Deterioration

  • Enzymes break down proteins over time

    • Must deactivate enzymes before food can be stored

    • Heat destroys enzymes

  • Fats and oils can oxidize in storage

    • Gives off flavors

    • Need airtight packaging or antioxidant additives

Importance of food drying

Thank You

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