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56 Cards in this Set
- Front
- Back
NLEA
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-National Labeling and Education Act of 1990
-Mandated numerous changes in food labeling |
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Food Labels
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1. Name
2. Net weight 3. Name & Address of manufacturer/packer/distributor 4. Ingredients list 5. Grades 6. Nutritional Info 7. Shelf Life data 8. IF standard of identity - clearly labeled 9. IF requires addt'l ingredients/further prep |
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Imitation
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Used when a product resembles a standardized product but does not have an equal nutritional value
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Protein Hydrolysates
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Source of protein must be identified, unlike past which use a common name
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Sulfites
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All foods that are sulfited must state the sulfiting agent
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Food Label Grades
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-USDA grades all foods except seafood
-State health agencies authorized by FDA may grade - Inspection sticker (safe/wholesome/sanitary) -NOT mandatory, not dependent on nutritional quality |
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Transfat
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Listed on label as of January 2006
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DV
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Daily Values, % based on 2000cal diet
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Saturated Fatty Acids
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-Completely saturated with H atoms
-Solid @ room temp |
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Unsaturated Fatty Acids
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-Contain double bonds btwn adjacent C atoms (Mono, Poly)
-Lower melting point, Liquid @ room temp -1+ double bonds oxidize more readily --> rancidity |
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Factors Accelerating Fat Oxidation
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1. Heat
2. Certain wavelengths of light 3. High Energy Radiation 4. Certain metal ions |
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Maillard Reaction
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-Reducing sugar and a free amino acid
-Onion, Bread Crust, Soda |
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Caramelization
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-Removal of water from the sugar molecules by heat, changes structure of sugar
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Major Causes for Food Spoilage
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1. Microbial
2. Physical 3. Chemical |
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Basic Food Preservation
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-Pasteurization: inactivates many microorganisms using heat
-Fermentation: lowers pH, inhibits MO -Pickling/Salting/Sugaring: lowering pH and/or Aw inhibits MO growth |
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Heat Transfer
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1. Conduction
2. Convection 3. Radiation 4. Combination of above -Destruction of MO based on time-temperature relationship -Pathogenic spore-forming bacteria are target -C. Bot = very heat resistant |
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Conduction-Convection
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collision of hot particles with the cooler ones
-changes in food (juices in large pieces of meat) --> convection |
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Convection-Conduction
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circulation of warm molecules
-more effective -less time to reach target temp -rapid heating -changes in structure (gelitization of starches) --> conduction |
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Radiation
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-transfer of energy by electromagnetic waves
-fastest method of heat transfer -transfers heat directly from source to food -contact surface reduces amount of heat |
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D Value
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Time in mins @ a specific temp to reduce the # of MO by one log cycles
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Z Value
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Temp required to decrease the time necessary to obtain one log cycle reduction of cell #s to 1/10 of the original value
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Processing of Low Acid Foods
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-Exposure to a temp for a period equal to # D values based on acid level of food
- pH 7-4.5 -High Temp Processing = 240-250F |
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Processing of High Acid Foods
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-Boiling water processing = 212* F
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Still Retort
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-containerized and heated in a steam environment w/o agitation
-Temps over 250* F may burn product -Heating time usually 30-45 mins |
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Agitating Retort
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-Agitated during cooking
-Allows high temp, convection heating -Reduces time to reach final temp (10-20% of still retorts) |
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Hydrostatic Retort
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-Cans flow continuously
-Uses hydrostatic heat to control pressure -Agitating system |
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Canning
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1. Pretreatment (clean, cut, inspect)
2. Blanching (steam or water) 3. Filling & Creation of Vacuum 4. Sealing the cans (hermetic seal, anaerobic inside) 5. Processing (retort @ 250F @ 15psi up to 2 hrs) 6. Cool the cans 7. Pack the cans in cases |
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Vacuum in Cans, WHY?
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1. Minimize swelling
2. Minimize oxygen from headspace 3. Prevent buckling during retort |
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Vacuum in Cans, HOW?
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1.Add hot food to container and seal
2. Use cold product but pass through a steam box uncovered 3. Pull a vacuum manually 4. Steam Jet vacuum |
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Liquid in Cans
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-Brine/Sugar for Veggies
-Sugar/Syrup for Fruit -Liquids speed up retort due to convection -Solid packed foods heat through conduction -->slower |
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High Temp - Short Time (HTST)
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-Liquids and Purees
-280-300*F for 15-45 secs -May use culinary steam to heat -Kills bacteria and their spores, added steam removed -Product filled into aseptic pack and sealed (Aseptic Fill) |
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Hot-Fill-Hold
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-High acid, low pH foods
-170-190*F for 25-30 mins -Kills all vegetative cells -Spores not killed |
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Sous-Vide
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-French, "under vacuum"
-Food packaged under vacuum and refrigerated till used -PROBLEMS: C. Bot outgrowth -Only allowed under FDA license |
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Dehydration
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Almost complete removal of water.
-Control of environmental conditions: humidity, temp, air flow, sanitation -Moisture 1-5%, Shelf life 2+ yrs |
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Quality Defects in Dehydration
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-Loss of flavor compounds & nutrients
-Browning -Texture Collapse -Liquid Oxidation -Case Hardening |
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Objectives of Dehydration
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-Prolong storage
-Preserve quality characteristics -Reduce product volume -Decrease distribution costs |
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HT - Heat Transfer (Dehydration)
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Transfer of heat from one body to another by conduction, radiation or convection
-Moving of hot air -Heat transfer to water on surface -Water on surface gains heat energy and evaporates forming a water vapor |
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MT - Mass Transfer (Dehydration)
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The movement of a constituent of the food from one location to another. Usually involves a change of state.
-Removal of water vapor by cooling air -Water from interior move to the surface by osmosis and diffusion |
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4 Factors affecting Heat & Liquid transfer during Drying
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1.Surface Area: greater surface area, faster drying
2.Temperature: greater temp, faster drying 3. Humidity: Higher humidity, slower drying 4. Atmospheric Pressure: Lower pressure, lower temp |
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Drying Curve
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-Lose water at a changing rate
-Water lost rapidly from surface -Outer layer creates insulation barrier preventing rapid heat transfer -Reaches normal equilibrium in relative humidity -Rapid to slow loss of water (graph) |
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Solute Concentration & Binding Water
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-high in sugar or other solutes dry more slowly
-Free water is removed |
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Drying Techniques
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*Sun - H2O removal using heat of sun
*Hot Air - hot air to evaporate H2O *Spray - atomized particles of a fluid are dried in contact with heat *Fluidized Bed - steam of hot air on mess beds *Vacuum - H2O removed under pressure *Drum - passed btwn 2 heat rollers *Freeze - frozen and sublimed |
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Refrigeration
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Process of removing heat from a confined space and objects within that space for the purpose of reducing/maintaining the temp below the surrounding atmosphere
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History of Refrigeration
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- 1850's in the US
- 85%+ of our food is refrigerated - home refrigerator WWII - Gentle/Short time preservation - 40-45*F - MO grow more rapidly above 50*F, but as long as H2O till 15*F (slows down, doesn't stop MO) |
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Cooling Capacity of Ice
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- Greatest point when melting
- 1lb of ice melts, lowers temp of 24lbs of food by 6*F |
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Refrigeration: How it Works
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- Refrigerant, Expansion Pipes, Compressor, Condensor
- Refrigerant liquid to gas - Liquid gains heat energy, gas changes to liquid it loses heat energy |
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Requirement of Refrigerated Storage
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- Low temp
- Air Circulation - Humidity Control (80-90%) - Modified Gas Atmosphere - Factors that can affect: Insulation, Door Opening, Quantity of hot product added, Refrigeration rate of food |
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Freezing
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- 1920, Clarence Birdseye
- 32* F, solutes lower freezing point (concentration increases, freezing decreases) - Free Water freezes first - The addition of 1 mole of any nonionic substance to 1L of H2O lowers the freezing pt by 1.885*C - Processors freeze at 0*F (must be maintained during transport and storage) |
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Preservation effect of Freezing
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- Spoilage is result of high AW
- Temps lower than 32*F --> crystallization and freezing - Crystalized water is not available to MO |
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Slow Freezing
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- H2O molecules start crystallizing
- Time to migrate to ice crystals already formed, making large crystals |
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Quick Freezing
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- Ice crystals made in their tracks, no time to migrate
- Make small crystals out of local water molecules - Temp must fall 32-25*F in 30 mins 1. Smaller ice crystals 2. Soluble components move to a lesser degree 3. Chem & Bio Rx rates reduced - -76*F all detectable H2O frozen |
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Freezing Methods
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1. Air Blast
2. Fluidized Bed (Peas) 3. Dehydro 4. Plate (packaged, btwn two plates) 5. Liquid (Nitrogen) 6. Slow 7. Slush 8. Scraped 9. Sharp 10. Pressure plate |
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Temperatures Abuse
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-Must be thawed properly to avoid extended exposure to ambient temps. Drastic changes in quality can occur in short period of time.
- Enzymes and/or microbial induced changes can occur |
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Changes during Storage of Frozen Foods
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*Physical: crystallization, loss of volatiles, structural breakdown
*Chemical: protein denature, lipid oxidation, oxidation, color and flavor loss *Enzymatic *Microbial (rare) |
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Chemical Changes during Freezing
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*Enzymes/MO in fruits & veggies slowed down, not destroyed, though gradual decline
*Can cause color and flavor changes, loss of nutrients |
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Textural Changes during Freezing
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*Ice crystals formed cause the cells walls to rupture
*Softer texture *Most noticeable in fruits & veggies w/ high water content Factors: rate of freezing, fluctuating temp, moisture loss |