IFWA 1213 Sanitation and Safety Food Spoilage and Preservation

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IFWA 1213Sanitation and SafetyFood Spoilage and
Preservation 
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Autolysis

•     chemical breakdown of food products by
  substances within the food itself
  (enzymes) Enzymes    proteins that acts as
  chemical catalysts

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Common causes of food spoilage

• 1)   Improper storage temperatures2)  Incorrect
  storage times3)  Improper ventilation4)  Failure
  to separate foods5)  Delays between receiving
  and storage6)  Poor sanitation standards

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Food Classifications

•     three types 1. Perishable foods   
  spoil fastest without processing or
  preservation    tend to be potentially
  hazardous foods

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Food Classifications

• 2. Semi-perishable foods    longer
  shelf/storage times when held at optimum
  conditions 3. Non-perishable foods    most
  resistant    contamination normally from
  improper handling

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Food Preservation

•     four main objectives1)  lengthen lag phase
  of bacteria growth2)  delay undesired
  autolysis3)  minimize pest / physical
  damage4)  prevent microbial action

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Low Temperature Food Preservation

•     Reasons for use1)  slow growth /
  reproduction of organism2)  reduced chemical and
  enzymatic activity3)  easy to perform Problems
      microorganisms are not destroyed

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Chilled Storage (50 F to 59 F)

•     reduced temperature used for storage   
  examples are potatoes

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Refrigerated Storage (32 F to 45 F)

•     slow rates of bacteria growth    best
  suited for perishable or potentially hazardous
  foods     Factors that affect storage    
  Relative humidity     Ventilation / air flow
      maintains humidity level    controlled
  atmosphere    Modified Atmospheric packaging
  (MAP)

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Freezer Storage (O F and below)

•     reduced Aw due to solidification  Misconcep
  tions about freezing    spores can not survive
  low temperatures    damaged foods are ok to be
  frozen    blanching of fruits and vegetables
  performed denatures enzyme activity and kills
  some microbes    nutritional value may be
  lowered by freezing    no air needs to be
  removed when freezing    rancid, freezer burn,
  color changes

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Quick-freezing

•     reducing temp. to -4F in 30 minutes or
  less    smaller ice crystal formation   
  lower drip loss    slowed microbial and
  enzymatic activity

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Quick-freezing methods

• 1)  Blast freezer / chilled    food cooled to
  40 F     rapid air movement    low numbers
  of ice crystals formed due to speed of chill   
  retention of texture and moisture due to the lack
  of cell rupture 2)  Immersion (nitrogen, brine,
  sugar solution)
• 3)  Plate

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Sous vide

•     under vacuum Brief History    Early
  60s     Healthcare opportunities in the US
  and Sweden
•     70s     French influence     hotel and
  restaurant catering 

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Sous vide

•     80s     French railways haute cuisine in
  first class (quality concerns)     Bruno
  Goussalt determined parameters for
  time/temperature and shelf life
•     90s     branding of product and expanded
  use     Hyatt uses for heart healthy products

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Three classes or types

• 1) Hot Fill    Vacuum packaged product while
  still hot     Chilled instantly     Product
  is 95 raw when packaged    Used mainly for
  liquid products (soups, sauces, stews)

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2) Cook /Chill

•     Cook conventionally then vacuum packed   
  Product is fully cooked, cooled, packaged,
  pasteurized, chilled and stored     Used for
  inconsistent products (soups, stews, meatballs,
  buffalo wings)

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3) Sous Vide

•     Product cooked and pasteurized in
  package    Raw materials used and preparation
  is extremely important (product enhanced in bag)

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Sous Vide Example

•     Chicken breast grilled or seared quickly
  (grill marks), pre cooled to low bacteria growth,
  packaged under a vacuum environment, fully cooked
  and pasteurized, prechilled to stop the cooking
  and let the product rest and finally frozen    
  Shelf life of 18 months

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Benefits from its use

•     Retains / enhances tastes and odors   
  Reduced seasonings used    Increased shelf
  life    Batch production increased
  consistency    Reduced food costs   
  Increased menu variety    Reduced bacteria
  growth (no TDZ)

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Control points to note

•     sanitation concerns    Botulism

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Thawing Techniques

•     never at room temperature    use
  refrigerator temperatures    perform under
  running water    consider part of cooking
  process    cook immediately if microwave thawed

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Slacking

•     increase temperature in preparation for
  cooking

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High Temperature Food Preservation

•     two methods
• 1. Pasteurization    product heated either to
  145F for 30 minutes or 161F for 15 seconds
  cooled immediately    does not destroy all
  microbes therefore refrigerate product

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2. Sterilization

•     high temperature stored in hermetically
  sealed containers    Three classifications
  based on pH     Low acid foods (pH above
  4.5)     Medium acid (pH 3.7 - 4.5)     High
  acid (pH

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Aseptic canning

•     separate sterilization of container and
  product, packed in sterile environment

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Dehydration

•     lower water activity level    four
  types     sun drying     mechanical (spray,
  tunnel, drum)     freeze drying     smoking

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Chemical Preservation

•     use of nitrates, sulfites, organic
  acids    can also use salts and sugar   
  reduces water activity

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Irradiation 

•     exposure of food to gamma rays or UV
  light    regulated dosage