Nusc 3233 Final Exam
Misconceptions with Food Allergies
"Since I am allergic to peanuts, I cannot eat anything with peanut oil" Explanations: Virtually all food allergens are proteins The process of refining oil removes the protein Caution with natural, cold pressed or flavored oils
Perishable heated foods
-Baked products -Salad dressings or emulsions break when frozen Use of safflower oil (crystallizes at -7°C) -Meringues Considerable loss of quality during frozen storage -Starched-thickened mixtures curdle Tendency of starch to retrograde Amylopectin versus Amylose in starch
Freezing:
-Enzyme activity can lead to the deterioration of foods quality. -Enzymes present in animals, vegetables and fruit promote chemical reactions, such as ripening. -Freezing only slows the enzyme activity that takes place in foods. It does not halt these reactions which continue after harvesting. -Enzyme activity does not harm frozen meats or fish and is neutralized by the acids in frozen fruits. -Freezer burn does not make food unsafe, merely dry in spots. -is caused by air reaching the surface of the food -example: frozen strawberries-mushy
Canning convection/conduction
-Liquid foods are heated by Convection -Solid foods are heated by Conduction -Cold -Point: Coldest area of food in a can being heat-processed
Logarithmic order of Death
-Percentage of bacteria and bacterial spores killed per minute at constant temperature -A deficiency in one minute of heating can make critical difference in the number of pathogens
Immune System
-Protect against disease -Distinguish healthy tissue from foreign pathogens -Innate vs Adaptive Response -Disorders: Autoimmune Inflammatory Cancer
Microorganisms versus spores : Clostridium Botulinum
-Spore forming, anaerobic microorganisms that need to be destroyed during the thermal processing. -Spores are much more resistant to everything including thermal processing.
Options for Canners
-Still Retorts -Agitated Retorts -Pressure canner -Containers- Cans, retort Pouches ex. horizontal retort, vertical retort
Changes in Nutrients during Dehydration
-Sugars: Can have browning reactions -Proteins: May become partially denatured -Starch and Gums: Might lose ability to absorb moisture
Thermal Death Time Curve
-The higher the temperature the quicker the microorganisms die. -Defined as: Comparison of the rate of death of pathogenic microorganisms over a range of processing temperatures. -By processing under pressure, the time is reasonable
Irradiation
-disease causing germs are reduced or eliminated -nutrition value of food is preserved -decreased incidence of food borne illness -reduced spoilage in global food supply -increased level of quality assurance in international trade of food products Gamma rays from 60Cobalt and beta particles Goal: Kill microorganisms and inactivate enzymes without altering the food Public resistance for perceived potential hazard Spices approved by FDA
Bacteria
1-3 µm Prokaryotic organism They can form spores Reproduce by fission
Steps for Canning of Foods
1. Clean, eliminate bones 2. Cook briefly to reduce bulk: Spinach 3. Leave 1/2 to 1 inch headspace 4. Jars are sealed 5. Process at correct t and T
Methods of Preservation what it does
1. Freezing- Kills some microorganisms and slows growth of others. 2. Canning- Kills all microorganisms 3. Pasteurization- Kills harmful microorganisms, does not permit long storage time **At moisture below 13%, food can be stored in shelf for long periods of time** 4.Drying: Dehydrates microorganisms 5. Irradiation Used to limited extent. Likely to increase in the future 6. Salting Sometimes used to preserve fish and meat 7. Sugar and Pickling Provide hostile environment for microorganisms
Bulging of Cans
1. Microorganisms spoilage microorganisms/ Flat sour spoilage Pathogens 2. Chemical Bulging Sulfide spoilage:Hydrogen sulfide gas liberated /Clostridium nigrificans 3. Mechanical Bulging mishandling of the can
Foods that can be frozen
1. Perishable raw foods meats, poultry, fruits and vegetables 2. Perishable heated or cooked foods Blanched vegetables, T.V dinners, baked items 3. Semi-perishable foods bread, dough products, cheese, butter 4. Non-perishable foods Nuts
Food Allergies background
150-200 Americans die each year Effects: 2% adults 4-8% children Often occurs with: asthma, eczema, other food allergies Can occur at anytime, to anyone Can change over time Can be outgrown
Spores
A resistant form of the bacteria Waits for the right time to grow
Antigen
A toxin or other foreign substance Induces an immune response Often the production of antibodies Recognized by highly variable antigen receptors of the adaptive immune system B-cell receptor or T-cell receptor Allergies: antigen is the allergic component Soy, wheat, fish, shellfish, fruits, vegetables, corn, spices, synthetic and natural colors, chemical additives, etc.
Peanut Allergy (continued)
Allergy can be to protein or oil Most severe symptoms: Collapse and cyanosis Subjects with history of asthma more likely to develop severe reactions 13% of subjects admitted to hospital because of a reaction Antihistamines most common medication
Causes: Initial sensitization
Allergy requires an initial sensitization which may often occur in childhood Development of allergy
Type IV Allergy-late phase response
Also called cellular or delayed hypersensitivity Involves reaction of sensitized cells usually lymphocytes-migrating Symptoms appear 6 to 24 hours after consumption of food
Food Allergy deffinition
An adverse reaction to a food or food component involving the body's immune system
Immunoglobulin E (IgE) antibodies
An immune response leading to the formation of IgE Hyperactive response- IgE antibodies are produced Released by B-cells Identify allergy agents as harmful Bind to surface of protein-tagged Binds to Mast cells Initiate allergic response
Food Allergy description
An immune response to a food or substance Cross-sensitivity/reactivity Normally a protein or glycoprotein Tertiary or quaternary structures that prevent degradation Initiate IgE antibodies Allergic reaction
Microorganisms of Concern
Anaerobic Thermophylic Spore-forming
Other negative reactions to food
Any negative reaction to a food is not a food allergy Food allergy is a very specific reaction involving the immune system There are other food sensitivities called Food Intolerance
Wheat allergy vs celiac disease: Celiac Disease
Auto-immune disorder Abnormal reaction to gluten Specifically gliadin Found in wheat, barley, rye, oats "Intolerance"
Microorganism involved in Food-borne Illness
Bacteria Viruses Parasites Molds Yeast
Food Allergy take home messages
Can occur at anytime Can occur to anyone Read labels Be aware of symptoms Mild symptoms can become severe Be aware of family/friends will allergies If suspected anaphylaxis call 911
Other common foods that cause allergies
Carrots Spinach Mangos Strawberries Plums Kiwi Onions
Salmonella poona in 2015
Cucumbers Case Count: 732 States: 35 Deaths: 4 Hospitalizations: 150 Recall: Yes
Allergic reaction: symptoms
Digestion affects timing and location of an allergic reaction Itching in the mouth as the food is eaten Abdominal pains, vomiting and diarrhea when it reaches the stomach and small intestine -Drop in blood pressure as it reaches the bloodstream -Eczema or hives as it reaches the skin -Bronchospasm (wheezing) when it reaches the lungs
Sulfuring
Exposure of cut fruits to the smoke fumes created by burning sulfur flowers to retain a bright color during drying
Determining food allergies: Double Blind Placebo
Food challenges Experiment conducted by a certified allergist, under close watch "Gold standard" for diagnosis Capsules with allergen Capsules with placebo Double blind Effective for determining what causes allergic reactions
Commercially sterile
Food that has been heat processed enough to kill all pathogenic microorganisms and spores
Unsafe Product
Food that results in an "injury" to the consumer 3 injuries: biological, chemical or physical hazards Microbiological hazard, most common cause of food-borne illness
Allergic reaction: symptoms
May range from relatively short-lived discomfort To anaphylactic shock and Death Reaction can differ every time
Unexpected sources of peanuts
Sauces such as chili sauce, hot sauce, pesto, gravy, mole sauce, and salad dressing Cookies, and hot cocoa Egg rolls Potato pancakes Pet foods Gourmet pizzas Asian and Mexican dishes Vegetarian meat substitute products Glazes and marinades
Food Safety
From the farm to the table Food Paradox Life versus death 1977 Hepatitis A; Michigan Frozen strawberries 2011 Listeria contamination in cantaloupes 2015 Salmonella in cucumbers: Multiple states
Food Intolerance what it is
Generally localized Transient Rarely life threatening Exception: Sulfite sensitivity Lactose Intolerance is a good example Different from milk allergy Bloating and gases versus life threatening
Causes: Inherited predisposition
The ability of a given individual to form IgE against something as benign as food Someone with two allergic parents is more likely to develop food allergies than someone with one allergic parent
Pennsylvania Hepatitis cases excess 500
Green onion
Heat of Vaporization
Heat energy absorbed by water as it changes state from a liquid to water vapor. Evaporation favored by *Relative humidity: low *Air Temperature: Warm *Air is circulating above food
Latent Heat of Crystallization
Heat released during transition from the liquid state (higher energy) to the frozen stage (lower energy)
Convection
Heating by convection is influenced by the shape and composition of food.
Preserving with Sugar
High sugar concentrations *increase osmotic pressure and *kills microorganisms
Identify between Allergies or intolerance?
Identify symptoms Identify food(s) Keep track of timing of reaction Testing (skin test, blood testing, food challenge) Elimination diet Food avoidance
Determining food allergies: Elimination Diet
If unsure of what food is causing allergic symptoms Remove suspected foods from diet for 3-4 weeks Slowly begin re-introducing foods/food groups Carefully note symptoms after each meal Consult an allergist/nutritionist
Wheat allergy vs celiac disease: Wheat allergy
IgE mediated response to wheat protein Abnormal reaction to wheat, can tolerate other grains Common contact allergy Occupational exposure Non-celiac gluten sensitivity Specifically gluten allergy No intestinal damage
Responsibilities of Allergic Individual
Individual has to be aware Make sure it is a true allergy Be informed about what is present in foods Have a medical adviser
Food Allergy Difference
Involves immune system Triggers immune response Can be life threatening Hives, itching, skin rash, swelling Respiratory complications Gastrointestinal problems Problems maintaining equilibrium and consciousness
Type I Allergy- acute response
Known as food anaphylaxis or immediate hypersensitivity Symptoms are a result of release of pharmacologically active substances IgE and Histamine Reactions occur within minutes to a few hours after ingestion of food Reaction can subside or progress to late phase reaction
"New" Bacteria (Emerging Pathogens)
Listeria monocytogenes E. Coli Campylobacter
FALCPA Labeling
Major Food Allergens must be identified Common name or usual name of ingredient Food source name Examples: Flour (wheat) Whey (milk) Contains wheat, milk and soy Produced in a factory where peanuts are handled
Food Infection and Poisoning
Major Health Problem for Industry Between 6.5 and 33 million cases/year 9,000 deaths/year
Food Infection and Poisoning to cause disease
Microorganisms can either grow in food Or multiply and cause a toxin
Types of foods associated with allergies (Big Eight)-FDA
Milk Eggs Soybean Wheat Peanuts Fish Shellfish Tree nuts
Clostridium Botulinum
Most dangerous of the common forms of spoilage in canned foods Types A, B, and E Neuro-toxin Lethal
Supercooling
Reduction of the temperature of water below freezing until crystallization begins Temperature then rises to 0 °C due to latent heat of crystallization
Histamine
Nitrogenous compound Blood vessels: vasodilation, fall in blood pressure Anaphylaxis Mucus membranes: causes fluid to escape from the capillaries to the tissues Runny nose, watery eyes, sneezing Gastrointestinal system: causes increase in pH of stomach and intestines Diarrhea, abdominal pain, stomach cramps, vomiting
Meats and Poultry
No treatment before packaging Changes in color and flavor Unsaturated fat promotes rancidity Drip loss = losses in volume and juiciness. Rapid freezing Avoid formation of large crystals
How many food allergens have been identified?
Over 170 have been documented in the literature MAS (Major Serious Allergens) Classifications: Big eight Second eight
Salmonellan background
Over 2,000 serotypes Cause diarrhea and systemic infections Fatal in susceptible individuals 4 million infections in U.S./year Raw foods of animal origin Contaminated fruits and vegetables DESTROYED BY HEAT
Food-borne toxin-mediated infection
Results from eating a food containing a large amount of disease-causing microorganisms Microorganisms produce toxin after ingested They colonize the human intestine
Infection:
Results from eating food containing living harmful microorganisms
Methods of Food Preservation: Why
Safety Retard growth of microorganisms Kill bacteria, yeast and mold Unsafe foods Gastrointestinal upset - death Quality is secondary to safety
Freezing
Popular method Relative convenience Good storage from 6 to 12 months Quality of food may deteriorate over time Does not compromise safety Deterioration depends on product Strawberries versus bread
Pickling
Preservation occurs by two ways Decreasing water activity Decreasing pH
Canning
Preservation of Food by heat Careful control of time and temperature Can be stored for 2 years
Freeze-Drying
Preservation of food by: *First freezing *then dehydrating Sublimation: Transformation from the frozen state to the gaseous state without liquefaction Products have a porous texture Used in strawberries Vegetables bananas
Bacteria types
Salmonella Shigella Clostridium botulinum Bacillus cereus Staphylococcus aureus
Food Intolerance Difference
Sensitivity Does not involve immune system Abnormal reaction to food Non-life threatening Typically lack of needed enzyme or specific chemical Gastrointestinal problems
Types of foods associated with allergies (Second Eight)
Sesame seeds Sunflower seeds Poppy seeds Corn Mollusks Beans Peas Lentils
Responsibilities of Food Manufacturers
Should try to avoid major food allergens as ingredients Warning of the presence of those food allergens Even micrograms can be harmful for certain people
Determining food allergies: Skin Testing
Skin-prick test Easy Quick results Allergens are placed directly on the skin If a hive appears, it is considered "positive" IgE antibody mediated responses
Listeriosis, 2015
Soft cheese Case Count: 24 States: 9 Deaths: 1 Hospitalizations: 22 Recall: Yes
Characteristics and Symptoms of Peanut Allergy
Study with 622 self-reported peanut allergic subjects 90% reported reacting after eating less than one nut 50% reacted to touching a peanut Symptoms appeared in less than 30 min for 93% of subjects
Sulfite Sensitivity
Sulfur dioxide (SO2) added to wines to help control microbial growth Individuals lack the enzyme sulfite oxidase Symptoms: asthma (wheezing), headaches, hives, anaphylaxis
Preserving with Salt or Sugar
They both decrease water activity This does not permit the microorganisms to thrive Used since ancient times
Mast Cells
This cell occurs in areas typical of allergic reactions (local response) Nose and throat, lungs, skin, and gastrointestinal tract Releases histamine
Dehydration method
This method has been practiced for at least 3,000 years Drum drying Spray drying Vacuum and Self drying Atmospheric belt drying Cabinet drying Tunnel drying Bacteria do not survive at moisture below 16%. Molds can survive at 13% moisture
Methods of Freezing
Timing is everything: Sharp Freezing (slow) Still air ( T -23 to -30°C) Blast Freezing (fast) Air blast freezers (-30 to - 45°C) Indirect-contact freezing (fast) Placing packages of food in contact with cold shelves or passing liquids through a chilled tube Cryogenic liquids (fast) Substances that are liquids at extremely cold temperatures
Food Allergen Labeling and consumer Protection Act of 2004
To help Americans avoid health risks posed by food allergens Passed by Congress in 2004 Law applies to ALL foods whose labels are regulated by FDA All food except poultry, most meats, eggs, alcohol Must list "food source names" that are or contain protein derived from "the big eight" Problems with contamination
Food-borne Intoxication
Toxins are odorless and tasteless Capable of causing disease after microorganisms has been killed Some toxins are present in foods naturally Examples mushrooms and puffer fish
Salmonella typhi
Typhoid fever
Canning at Home
Use Pressure Canner Ensure killing C. botulinum Water bath canning pH < 4.5 Acid Foods
Duration of Drying
Varies with: Type of food Thickness of food Drying conditions
Doses
Vary depending on Food 7500 rads halts sprouting of potatoes for 2 years 50,000 rads kill insects 150,000 rads keep berries for 3 weeks 1,000,000 rads keep meat at 0°C for 2 months
Preparation of Food
Vegetables are washed and blanched Fruits are washed Meats wiped clean Foods are usually sliced into small pieces
Fruits and Vegetables
Washed before freezing Vegetables are blanched Grape juice pasteurized Complications with processing equipment
Intoxication
When toxins or poisons from bacteria or mold growth are present in ingested food
3 Major Food-borne Illness
[1] Major Microorganisms [2] Infection/Intoxication [3] Factors that prevent Food-borne Illness
Cyanosis
a bluish discoloration of the skin resulting from poor circulation or inadequate oxygenation of the blood
Sugar preservation examples`
apricots, raspberries
Salmonella enteriditis
associated with raw eggs 1 in 10,000 eggs Contamination occurs inside the chicken Death in elderly people
Salt Preservation examples
fish, meat
Problem with Tomatoes
pH can be higher than 4.5 Onions, peppers increase pH Better to use pressure canning Addition of bottled lemon juice to ensure low pH
Glycoprotein
protein with carbohydrate group attached to peptide chain
