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- Protein efficiency ratio.
- Gives an index of the nutritional value of a food.- determined by accounting for the % of the most limiting aa relative to a reference protein.
- Used as a source of energy.
- Nutrient CHO- sugars such as glucose and sucrose Glucose and fructose) and lactose (Galactose and glucose)
- Starches, including dextrins (complex CHO)
- Glycogen, the end product of CHO digestion. Glucose in the body
Glucose + oxygen--> energy + CO2 + water
- Fiber, (bran- cellulose, hemicellulose, lignin)
- Pectin- a structural CHO in fruits. Partly digestible. Holds water together. When fruit ripens, pectin breaks down.
Fats or Lipids
- One gram of fat yields 9 kCal.
- One gram of CHO yields 4 Kcal
- CHOs and fats are interchangeable as fuel foods.
- Saturated- no double bonds.
- Solids at room temp or oils at rooms temp
- Some fatty acids are essential - linoleic and linolenic acids
- Often found in the form of triglycerides
- glycerin + 3 fatty acids
- Vitamins and minerals essential to the body.
- There are water-soluble and fat-soluble (DEAK)
- Micronutrients are used for enzymatic processes
- (Calcium in blood clotting)
- for aiding in tissue and organ maintenance
- (Vitamin E for anti-oxidant protection)
- and for proper functioning of organs and glands
- (Iodine for the thyroid gland)
What are some of the diseases brought on by nutritional deficiency?
- Scurvey- vitamin C- loss of teeth hemorrhagic skin
- Rickets- vitamin D and calcium- weak bones distorted ribs
- Pellagra- Niacin, B5- Skin rash, bloody diarrhea, mental disorder
- Anemia- Iron- paleness of skin, short of breath, low hemoglobin
- 1 micrometer is size
- Reproduce by binary fission- 1-->2-->4-->16
- Rapid reproduction, dividing every 20 min
- Some have ability to form spores (dormant form of organism, that have a coating similar to a seed) that are resistant to environmental stress : freezing, radiation, acid
- Spores will not grow in high acid or low water activity (Aw) conditions.
- Some species are motile, while others are not.
- Some species are considered beneficial- living on our body. We get ill when an imbalance occurs.
- Some are pathogenic.
- Acetobacter makes vinegar (not beneficial for wine makers though)
- Salmonella makes you sick
- Average size is 10X bigger than bacteria. from 1-10 micrometers.
- Reproduce mostly by budding, fission or by spore formation
- Some species produce spores, some do not. This can be sexual or asexual reproduction
- Single celled or multicellular and Eukaryotic
- Generally not heat resistant
- More resistant to highly acidic or low water activity (Aw) conditions (Compared to bacteria and yeast)
- Reproduce by sporulation, can be asexual or sexual
- Multi cellular
- Strict Aerobes- require oxygen. Grow on surface of foods
Intrinsic Growth Parameters
- Moisture Content
- Nutrient Content
- Antimicrobial Constituents
- Biological Structures
- Most microbes grow best at pH values around 7.0 which is neutral
- Most fruit has lower pH than veggies thus molds tends to spoil fruit and bacteria spoil veggies
- Some foods tend to resist changes in pH and are said to have buffering capacity
- Adjustments in pH can help preserve food
- Olives are basic, but we process them
- Most food is acidic
- Drying is one of the oldest preservation techniques where moisture as a nutrient is removed from food
- Water requirements of MOs should be expressed in terms of water activity (Aw) in the food environment
- The Aw of most fresh foods is above .99
- Several preservation methods also change the Aw of the food:
- Salting, adding sugar to fruit to make preserves, using additives or ingredients as humectants
Intermediate Moisture Foods (IMF)
- Foods that are intermediate moisture range but have prolonged shelf-life because they contain water-binding agents, or humectants
- Humectants- chemical compounds that bind to and absorb water consequently lowering the Aw. Ex: Glycerol, sorbitol, other sugars, propylene glycol
- Energy Source- sugars alcohols or amino acids
- Nitrogen source- primary is amino acids (proteins)
- Vitamins and related growth factors
- Lactenin in fresh milk designated an anticoliform factor
- Lactoperoxidase in raw milk effective against some streptococci
- Lysozyme in egg white and tears
- Benzoic acid in cranberries
- Lipids and essential oils
- Skin on fruit- prevents moisture loss and insect entry
- Shell on nuts
- Hides of animal
- Outer shell and membranes of eggs
Extrinsic Growth Parameters
- -Temperature of storage
- Thermophilic range- 110-160 F optimum 131-151
- Mesophilic range- 70-110 F optimum 95-98
- Psychrophilic (Refridge) range- 45-86 F optimum 68- 77 F
- - Relative Humidity of environment (High humidity= foods pick up moisture)
- - Presence and concentration of gases (Packaging)
Occupational Safety and Health Administration
Microorganism Spoilage in Foods
- MOs are interested in reproducing themselves.
- Geometric progression is unlike enzymatic or oxidative spoliage which is linear because the reagents are fixed.
- By-products are excreted from the MO cells where they can cause spoilage or perhaps a desired change
- These by-products can accumulate rapidly bc of rapid growth
- The growth requirements of MOs both intrinsic and extrinsic, determine what foods they are going to spoil
MOs can be beneficial by the by products they produce
- Vitamins K and B produced by intestinal bacteria
- Flavor compounds like diacetyl produced by lactic acid bacteria
- Pigments like orange pigment produced by yeasts
- Food fermentations can be processes that use MO to produce a desirable effect in foods.
- A fermentation is the metabolic process in which the CHOs and related compounds are oxidized with the release of energy in the absence of any external electron acceptors (O2) (anaerobically)
- Potential problems:
- Growth of undesirable MOs
- Phage (virus) Growth
- Antibiotic or antimicrobic production
- All can result in inhibition of the desired culture
- Fermentations must be carried out under strict QC. Good sanitation is desired
- Produces acid (lactic) or R-OH and gas (CO2)
- EX bakery products, alcoholic beverages
- produces only acid
- EX yogurt, buttermilk
- Caused by:
- Several species of bacteria
- some viruses
- other biological agents (Mad Cow)
- chemical agents
Food Borne Illness
- Pathogenic MO's cause food-borne illness
- Food poisoning is a common term used to describe two types of food-caused sickness
- Food intoxication
- Food infection
- occurs when MO's in the infected food grow and produce the toxin
- onset of symptoms are usually quick 2-8 hours after ingestion
- it is the toxin that gets you ill
- EX: Staphylococcus, Clostridium botulinum, C. perfringens, bacillus cereus, Aflatoxin, shellfish poisoning.
- Caused by the ingestion of sufficiently high numbers of a pathogenic MO. The MO invades cells.
- The pathogen grows in the human body rather than in the food.
- Onset of symptoms is usually longer than for food intoxication- 24 hours or more after ingestion
- EX: Salmonella, Shigella, Escherichia, Yersinia, Campylobacter, Vibrio
- Non spore forming, rod shaped, motile, facultative anaerobes
- Not heat resistant
- Optimum growth temp= 37 C, body temp
- Growth range- 4-47 C
- Usually ingestion of contaminated shellfish, eggs, milk, raw and cooked meats
Shigella - Shigellosis
- Non-spore forming, rod shaped, non motile, facultative anaerobe, requires very few MOs for infection.
- 10 species
- 4 to 7 day on set
- Associated with meats, shellfish, salads
- Symptoms are similar to bad salmonella
- Opportunistic pathogen = given the opportunity it can cause illness. most bacteria fall into this category.
- Traveler's Diarrhea
- Onset usually 24 hours after ingestion
- Fatalities are rare
- Mesophile with optimum temp= 37 C
- Rare food infection
- Cousin of the causative agent or etiological agent of bubonic plague- yersinia pestis
- Organism is a psychrotroph and found in beef, oyster, mussels and river water
- Associated with seafood or water, esp raw seafood. The sea animals are always filtering water and they pick up MOs and they build up.
- Cholera comes mainly from contaminated water supplies and is endemic in mainland Asia and pacific rim
- Mildly halophilic (loves salt), mesophilic, facultative anaerobe. Rod shaped, non spore forming
- Usually infects children or elders
- Affects the central nervous system- meningitis. May cause "flu-like" symptoms, spontaneous abortions, or infectious mononucleosis.
- Very hardy; cold and salt tolerant.
- 50% of water samples (rivers, lakes, and estuaries in UK) tested have this MO.
- Today, thought to be more predominant than salmonellosis or shigellosis.
- Associated with raw clams, poultry, pork, beef, and raw milk.
- Heat sensative, mesophilic and microaerophilic.
Sanitation in the Home
- Meat, eggs, poultry, and fish should be held at safe temperatures avoiding the danger zone - 40-140 F
- Use 50 ppm chlorine (hypochlorite) for sanitizing.
- 100ppm for critical areas
Center for Disease Control and Prevention
Center for Food Safety and Applied Nutrition
Morbidity and Mortality Weekly Report
Free of Pathogens
- Hazard Analysis and Critical Control Point System
- A system developed to ensure the safety of foods.
- HACCP is widely accepted and recommend for all aspects of the food industry.
- Currently HACCP is mandated as necessary for the seafood, meat, poultry and juice industries.
HACCP Seven Steps
- -Asses the potential hazards
- -Determine the CCPs where controls are necessary to eliminate or reduce hazards
- - Establish requirements and parameters to be met at each CCP
- - Establish procedures to monitor each CCP
- - Establish corrective actions if a deviation occur at a CCP
- - Establish procedures for verification that the HACCP plan is working effectively
- - Establish record-keeping procedures
- Estimated that there are 40-80 million cases of foodborne illness in the US each year.
- $74,000 in expenses per case to recover from a foodborne illness.
- Protein rich foods are the most common cause.
- Salmonella (infection) and stapylococcal food poisoning are the most common.
- People may be carriers of Staph on or in the nose throat and hands.
- 25% of the cases are caused by poor personal hygiene Heat leftovers and poultry to 165 F
Most Commonly Used FDA Approved Chemical Sanitizers
- Hypochlorite- Chlorine 50 ppm, 10 seconds for sanitizing, corrosive to steel, aluminum, silver plate utensils.
- Iodophor- Iodine 12.5 ppm, 30 seconds for sanitizing, noncorrosive, looses amber color as it weakens
- Quarternary Ammonium, 200ppm, 30 seconds for sanitizing, noncorrosive
Food Regulation and Regulatory Agencies
- It is a proper function of our govt to determine the wholesomeness and purity of a food protecting the consumer from economic fraud and health hazards.
- Laws require a basic need for implementation and public support.
- 3 Regulatory agencies have enforcement authority:
- - Food and Drug Administration (FDA)
- - Meat Inspection Division*
- - Meat Inspection Service *
- * apart of the food safety inspection service (FSIS) and US Department of Agriculture (USDA)
United States Department of Agriculture
Food Safety Inspection Service
- Hemolytic- Uremic Syndrome
- Found in Ecoli Patients 0157: H7
- Food Drug and Cosmetic Act, 1938
- Established the FDA as an agency
- Covered most things except food additives
The Food Additives Amendment to the Food, Drug and Cosmetic Act
- Includes the "Delany Clause" for carcinogenic materials.
- Introduced "GRAS" status
- Nutrition Labeling Education Act, 1990
- Went into full effect in 1994
- Food Allergen Consumer Protection Act
- 2004, but goes into effect in 2006
- Said items such as soy, wheat, egg, peanuts, treenuts, shellfish, and dairy had to be on the labels
- The Food Allergy and Anaphylaxis Network
- A well recognized consumer education organization
- International Food Information Council Foundation
- Mission to communicate science-based information on food and safety and nutrition to health and nutrition professionals and others
- A food is adultered if
- It is filthy, putrid or decomposed
- It is produced under unsanitary conditions
- It contains any substance deleterious to health
- Chemical- lead, pesticides
- Biological- MOs, ecoli
- Physical- wood, bone, fragments
- A food is misbranded if
- It has a standard of identity and fails to meet the standard
- It is wrongly labeled
- It fails to meet the standard for fill of container
Environmental Protection Agency
- Authorizes and regulated the use of pesticides. Monitors compliance and provides technical assistance to states
All labels must bear:
- -The name of the product
- - Net contents (in both common and metric units) or net weight, including liquid
- - Name and address of manufacturer, packer, or distributor
- Many foods are covered by standards of identiy
- - ice cream must have > 10% butterfat
- All ingredients must be listed- in order from most predominant by weight to least.
- Any additive, colorant, allergen, or protein hydrolysates must be listed
- Foods containing juice require percentage of total juice.
- a genetic recessive disorder where babies cant break down an amino acid called phenylalanine.
- They grow out of it by adolescenc.
- Enzymes catalyze chemical reactions
- An enzyme reacts with a substrate but does not become part of the final product.
- Enzymes are critical for life and cellular functions
- All life depends on enzymes to convert food nutrients into a utilizable form
- Enzymes are proteins.
- Cofactors help the substrate reach the product
- Temperature sensitive
- Has temp and pH optimum
- -some enzymes are active at freezing temps
- An enzyme may require a coenzyme or cofactor to function- this is the role of many micro nutrients
- Enzymes are classified in several ways, one of which is by substrate. Proteases act on proteins ect....
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