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91 Cards in this Set
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emulsion
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suspension of liquid droplets in liquid continuous phase
(o/w or w/o) |
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solid emulsion
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liquid droplets in solid continuous phase
(margarine/butter) |
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gel
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water in polysaccharide matrix (starch gels) or proteins (gelatin gels)
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functional properties of carbs
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-sugars and starches
-human bodies main source of E -should contribute 50% of our caloric intake -should be complex carbs (polysaccharides) |
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maillard browning
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occurs when reducing sugars rx w/ nitrogenous compounds (proteins, amino acids, amines)
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reducing sugar
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react with proteins and amino compounds to produce flavours and colours in foods (ie/maillard browning)
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sugar alcohols
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type of alcohol produced from the fermentation of sugars
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starch
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polymers of glucose joined by an alpha 1-4 link
bland |
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functional properties of fats
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lubricant
tenderizing power aeration aroma constituents can reach high temperatures good for cooking gradually soften when heated => "melt in your mouth" texture form part of emulsions act as emulsifiers |
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thickening by:
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agar, xanthan gum, alginates
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stabilizing by:
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agar, alginates
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suspending agent
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pectin
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fatty acids
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building blocks of all the fats in our bodies and the food that we eat
carboxylic acid with hydrolic C chain carboxyl group |
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phospholipids
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can function as emulsifiers
-diglyceride with charged group in place of the third glycerol -hydrophillic/hydrophobic ends |
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amino acid
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type of organic acid that is used to form proteins
made up of amino group and carboxyl attached to same carbon atom |
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foam
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air bubbles suspended in a protein matrix
solid foam = air bubbles in a solid phase |
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lipolytic rancidity
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spoilage of foods as a result of hydrolysis of fats on storage
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enzymes
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produced by living organisms to act as a catalyst to bring about specific biochem rx
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sucrose polyester
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sucrose molecule & 6-8 long chain edible fatty acids
olestra is made of them |
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sorbitol
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sugar alcohol
bulk sweetener 1.5-3 cal/g 60% as sweet as sucrose menthol like sensation |
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acesulfame-K
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non-caloric sweetener
200x sweeter than sucrose synergistic with other sweeteners |
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sucralose
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chlorinated molecule
3 OH groups replaced by chlorine 600x sweeter than sucrose non-caloric, heat stable |
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sensory properties of foods
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why we pick them
appearance flavour textural |
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flavour =
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taste + aroma
taste - water soluble, detected in the mouth aroma - fat soluble, volatile |
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bitter
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alkaloids
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heath canada
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food & drug regulations
standards of ID & composition for foods food additive regulations |
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Canada Food Inspection Agency (CFIA)
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food processing plant inspection
regulatory aspect of food safety grade standards labelling/packaging/advertising regulations |
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Food & Drugs Act and Regulations
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form foundation of consumer protection laws
contains descriptions for foods that outline what is allowed in those foods |
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food grades
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administered by CFIA under canadian agriculture products standard act & meat inspection act
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Clostridium botulinum
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produces toxin responsible for botulism
-growth inhibited by nitrites -anaerobic bacterium |
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food packaging requirements
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common name
net quantity name + address list of ingredients nutrition facts table durable life date + storage instructions bilingual labelling nutrition content + diet related claims |
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mould
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spores
foods of agricultural/aquatic origin often have them food with low pH and low water activities that would limit yeast and bacteria growth |
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yeasts
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produce by budding
tolerate more severe environmental conditions/grow slower than bacteria |
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need for food preservation
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to combat food deterioration by:
infestation by food pests inappropriate temps physical stress or abuse time rx with oxygen and light +/- moisture microorganisms food enzymes and other chemical rx with food |
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enzyme inactivation
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by heat, chemicals (antioxidants) and by controlling gaseous environment
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moisture
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addition/removal of water can lead to deterioration
changes in water activity influences chemical/enzymatic rx & microbial growth |
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oxygen
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oxidative rx decreases food & nutritive quality
-oxidative rancidity -often accelerated by light |
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hydrolytic/lipolytic rancidity
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induced in foods upon release of free fatty acids by very high temp or action of lipase enzymes
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pasteurization
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High Temp Short Time (HTST) processing
inactivate pathogenic bacteria & viruses in low acid food products -in acid foods to inactivate spoilage causing microorganisms |
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commercial sterilization
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destroys both spoilage and disease causing microO in acid & low-acid foods
-involves pre-sealing food in containers prior to heating |
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thermal death curve
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microbial death during heat treatment follows logarithmic order
bacteria killed at a rate that is nearly proportional to the number present in the system |
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used in inoculated pack studies
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PA3679
very heat resistant so if killed C. botulinium will definitely be killed |
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D-Value
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decimal reduction time
exposure to a specific temp for period of time required to kill 90% of the population -lower value = faster death |
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F-Value
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mathematically calculated number that describes the total lethal effect of the processes at the slowest heating point in a food container
-the lethality of heat treatment |
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Z-Value
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the number of degrees required for a specific thermal death curve to pass through 1-log cycle
-resistance of population to changing temp |
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concentration effects
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chem changes (rancidity) enzymatic rx (browning)
-meats become tougher due to protein denaturation concentration of components as water freezes |
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freezer burn
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formation of package ice & freeze dehydration
can produce unsightly food surfaces and loss of nutrients |
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freezing rate varies with
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temp difference
product thickness/geometry and heat transfer rate air velocity degree of contact |
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changes in food during freezing effected by
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rate of freezing
final storage temp stability of storage demo rate of thawing |
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minimize damage of ice crystals
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because can lead to loss of water once product is thawed
want many smaller ones instead of fewer larger ones |
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brine
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used in plate freezing to cool a metal surface
-packaged food rests on or slides against or pressed between cold metal plates |
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water activity
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defines proportion of water that is in free form
0.2 - 0.6 in dehydrated foods <0.6 no microbial activity ~0.3 chem rx begin |
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dehydration
& concentration |
implies removal of as much water as possible to impart a long storage life
some water removed from food to concentrate food constituents -not inherently shelf stable, requires other forms of food preservation |
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vacuum drying advantages
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high quality products
low nutrient loss better flavour retention less colour change |
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damages to food during dehydration
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cell/tissue shrinkage
case hardening chemical changes |
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Radiant Energy Vacuum
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vacuum keeps temp low
microwaves: ultra rapid E transfer |
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factors effecting dehydration
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surface area
temp air velocity humidity of drying air atmospheric pressure & vacuum |
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microbial antagonism
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use of live microO to produce desirable changes in the food, including acids, alcohols + other substances that inhibit the growth of other microO
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secondary starter cultures swiss cheese
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Propionibacterium shermanii
-produces propionic acid and CO2 from lactic acid Streptococcus thermophilus -heat tolerant, acid can be produced at higher cooking temperatures employed |
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mould used in blue veined cheeses
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Penicillium roquefortii
-active production of lipase which breaks down milk fat into free fatty acids |
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mould used in camembert & brie cheeses
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Penicillium camembertii
Penicillium candidum -leads to formation of mycelia (white rind) on cheese |
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fermentation
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anaerobic and aerobic breakdown of carbs and carb-like materials by microO
-proteins/lipids may be hydrolyzed and metabolized by microO in fermentation process |
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justified uses for food additives
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maintain nutritional quality
enhance keeping quality or stability attractive w/o deception essential aids to food processing |
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guidelines for use of food additives
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safe for continued use
not lead to deception results in advantage to consumer |
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ID standard
Compositional standard |
-state what the food shall be and defines a food or ingredient
-list mandatory and permitted ingredients in food |
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colouring agents in cheddar
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annalto and beta-carotene
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adding salt in cheese making process
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draw whey out
flavour inhibit growth of proteolytic and lipolytic spoilage causing microO provide conditions favorable to proteolytic action of rennet and lactic acid starter |
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curing and ripening
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leads to desirable changes in flavour and texture
-takes place @ 2C & 80& R.H. |
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fermentation preservation principles
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encourage of growth and metabolism of alcohol and acid producing microO to suppress growth and metabolic activities of proteolytic/lipolytic, spoilage causing microO
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ionizing food energy preservation principle
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ability of E absorbed to create free radicals without inducing radioactivity
-reactions they cause form the mechanism for the inactivation of microO enzymes and alterations of food constituents |
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radurization
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radiation pasteurization
-kill spoilage causing microbes to extend refrigerated storage life |
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radicidation
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kill or inhibit disease causing microO
absorbed dose <10kGy must be refrigerated because spoilage causing microbes still exist |
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radappterization
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=thermal commercial sterilization
all disease and spoilage causing microO capable of growing at storage temp are killed usually kGy > 10 (not allowed in canada0 |
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factors affecting food irradiation
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safety and wholesomeness of food
resistance of food to irradiation resistance of microO to ionizing E resistance of enzymes to ionizing E cost |
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toxicity
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the intrinsic or inherent capacity of a substance to damage a biological system
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hazard
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the capacity to produce injury under circumstances of exposure
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risk
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likelihood of occurrence and the magnitude of the consequences of an adverse effect
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solanine
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cholinesterase inhibitor
found in potatoes, esp when green |
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amygdalin
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cyanogenic glycoside
yields hydrogen cyanide with treatment with acid beta-glycosidases hazard when the foodstuffs are a large part of the diet |
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saxitoxin
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causes paralytic shellfish poisoning
"red tide" = high amount of saxitoxin in water being consumed by shellfish accumulates in tissue etc |
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domoic acid
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amnesic shellfish poisoning
neurotoxin, causes lesions in the central nervous system found in marine algae, accumulates etc |
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tetradotoxin
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puffer fish poisoning
thought to be synthesized by associated bacteria |
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listeria monocytogenes
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food infection
can grow in refrigerated and salted foods |
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HACCP
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hazard assessment and critical control point
best method for ensuring food safety, used in restaurants |
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FOSHU
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food for specified health use - japanese term for functional food
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functional food
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consumed as part of a normal diet, a food not a food constituent, physiological benefits and/or decrease risk of chronic diseases (beyond basic nutritional functions)
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nutraceuticals
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product isolated or purified from foods, generally sold in medicinal forms not in association with food
-physiological benefit or protection against chronic diseases |
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probiotics
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health promoting microO
-will increase intestinal microflora balance -can be ingested as a nutraceutical or a functional food |
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lactic acid bacteria
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non-pathogenic, gram positive bacteria that have lactic acid as a primary metabolic end product
-traditionally used in yogurt and cheese production |
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natural health products (NHP)
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products like: vitamins, menerals, herbal products, homeopathic remedies
-prevent diagnose or treat diseases, restore or correct function, maintain/promote health -may be derived from plants, animals, or microO |
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DKP
PKU |
diketopiperizine
phenyleketonuria |