Principles of Preservation - Week 9 Flashcards
Spoilage
the process in which a food deterioates to the point it is unediable
Preservation
Treatment of food to prevent or delay spoilage or growth of microorganisms
Economic/Social reasons as to why we preserve food
Minimizes waste
Minimizes Environmental Impact
Logistical advantages
Consumer expectations
Things that cause food deterioration
Bacteria ( Pathogenic or Spoilage) Moulds Yeasts Oxygen ( Oxidation of fats causing rancidity) Enzymes Pests
Pathogenic bacteria causing spoilage
E-Coli0157
Campylobacter
Spore forming C. Botulinum
Name a Spoilage bacteria and how it works
Lactobacilli
Breaks down nutrient material giving stinky odours
How do moulds work
Visible colonies leading to food break down
Require minimum Aw 0.8 and oxygen
Fact recall: Yeasts
Cab grow in acidic environemnts
Requires moisture Aw 0.9 minimim
Cause taint in food products and effect quality
Types of preservation
Salt Sugar Smoking Pickling Chemical additives Fermentation
Non chemical preservation
Heat (Pasteurisation)
Cold temp
Water activity (Dehydration, Aw control)
Oxygen removal (Vacuum Packaging, Modified atmosphere packaging)
Factors that effect deterioration
Type of food Temp Aw ( Freely available water for micro organisms to grow) Atmosphere pH Competition
How does salting work and what is it used for
Reduces Aw and deactivates enzymes
Used in meats and fish
How does sugar work and what is it used for
Causes bacteria to lose water
Fruits (preserves)
How does smoking work and what is it used for
Adds antibacterial chemicals and reduces the Aw
Used in fish but also things like cheese
(Can be for taste as oppose to
How does pickling work and what is used for
Vinegar lowers pH
Salt Solutions lead to fermentation which lowers pH
mainly in fruit and veg
