Transcript lecture 15x
Food Safety & Technology HLTH-120N Nutrition Lecture 15A “Food Poisoning” Objectives • Differentiate between food infection & intoxication • Identify several organisms involved in food-borne illness • Describe strategies for preventing food-borne illness • Explain the purpose of and risks associated with canning, preservatives, and irradiation. • Describe the risks & benefits of GMO’s & pesticides • Understand the GRAS list & food additive safety • Describe how pollutants build up in foods • Understand the labeling system for organic food Food-Borne Illness • Symptom or illness from food or water that contains an infectious agent or toxic substance • 76 million cases each year ▫ Over half unknown or unreported Who is at high risk? • • • • • Food Safety & Quality Regulation • USDA ▫ Meat, poultry & eggs • FDA ▫ All food products except meat, poultry & eggs ▫ Enforces pesticide use • CDC ▫ Aids in food safety education of the public ▫ Tracks the cause of food-borne illnesses • EPA ▫ Regulates pesticide use & establishes water quality Causes of food-borne illness • Food infection ▫ consumption of food containing living microorganisms (bacteria & viruses) • Food intoxication ▫ Consumption of food in which microbes have secreted poisonous substances called toxins Bacteria Incubation Symptoms Foods Campylobacter 1-7 days Jejuni Fever, headache, muscle Raw meat, poultry, pain, diarrhea fish; raw milk; water Salmonella 12-24 hrs Diarrhea, ab pain, chills, Undercooked eggs, vomiting meat, raw dairy, poultry, f/v E. Coli 2-4 days Diarrhea, ab cramps, Water, raw milk, nausea, kidney infection beef, uncooked f/v C. Botulinum 12-36 hours n/v, diarrhea, fatigue, Canned food, meat, muscle paralysis, double fish, honey vision, dry mouth Staphylococcus 1-6 hours Severe n/v, diarrhea, cramping Custard, cream filled baked goods, cream sauces, dressing, gravy Microbes • Helminths ▫ • Parasite: ▫ benefits from and harms its host • Fungi: ▫ plant-like & spore-forming • Prion: ▫ self-replicating protein particle causes mad cow disease (bovine spongiform encephalopathy (BSE) ) Microbes release toxins • Neurotoxins ▫ damage the system, cause paralysis ▫ C. Botulinum: found in bulging cans, foods improperly canned at home, raw honey • Enterotoxins ▫ target the system, causing severe diarrhea and vomiting • Mycotoxins ▫ secreted by fungi Toxins without microbes • Toxin present in food without microorganism • • Marine Toxins • Greening in potatoes: solanine Defense against the organism • Antimicrobial enzymes in • . in the stomach • • Activated immune system • Diagnose: obtain and culture a specimen • Stay hydrated! How Microbes multiply • In the “danger zone” ▫ to • Humidity • Oxygen • Acidity . Preventing Illness at home • Clean: Wash hands & surfaces often • Separate foods to • Chill foods to prevent growth • Cook foods to proper temperature Food Storage & preparation • Store foods in small containers, to reach degrees within hours ▫ Eat within 4-5 days • How should you thaw foods? • Traveling ▫ use bottled water and avoid ice & raw foods Reheating foods will kill __________ but not toxins Modern Preservation • Industrial Canning • Pasteurization • Packaging techniques • Preservatives ▫ (antioxidants, mold inhibitors, sulfites, nitrites, nitrates) • Irradiation • Genetic Modification Canning • Food is sorted & washed • Food is then blanched • Cans are filled & heated • Air siphoned out of cans & sealing • Heated & Cooled Pasteurization • Invented by Louis Pasteur to destroy microorganisms in spoiled wine • Involves quick heating ▫ Usually to 160 degrees for 15 seconds • Which products are pasteurized? Packaging Techniques • Aseptic ▫ Sterilized in flash heat & cool ▫ Placed in sterile container • Modified Atmosphere ▫ Oxygen in package replaced with inert gas • High-pressure ▫ Bacteria inactivated with extreme pressure Preservatives • • Antioxidants • Mold Inhibitors • Sulfites • Nitrates/Nitrites Food Additives • Flavoring agents ▫ essential oils, extracts, or spices • Flavor enhancers ▫ Examples: maltol and MSG • Food colorings ▫ Natural colorings ▫ Synthetic: Red #2, yellow #5, etc. Can cause allergic reactions in some people; use must be indicated on the product packaging Food Additives • Vitamins and other nutrients: ▫ Vitamins E and C (ascorbic acid): antioxidant ▫ Iodine ( ) helps to decrease ________ ▫ Vitamin D and calcium for bone health ▫ Folate (breads, cereals) to decrease neural tube defects during fetal development Food Additives • Texturizers, stabilizers, and emulsifiers • Thickening agents ▫ Pectin, carrageenan, etc • Humectants maintain correct moisture levels ▫ Sorbitol, propylene glycol • Desiccants prevent moisture absorption Food Additive Safety • Delaney Clause: ▫ “No additive may be permitted in any amount if tests show it produces cancer when fed to man or animals or by other appropriate tests” • GRAS list ▫ Safe by either research or consensus • Adverse Reaction Monitoring System ▫ Sulfites Food Residues • Chemicals that remain in foods despite cleaning and processing • Persistent organic pollutants (POPs): chemicals released into the atmosphere • Mercury and lead: neurotoxins • Industrial pollutants: PCB’s Irradiation • Eliminates bacteria & fungus in meats & poultry • Exposes food to gamma rays from radioactive metals • Approved by 50 countries & promoted by WHO • Can slightly change taste & smell of products ▫ Damages vitamins A, E, K and thiamin • Irradiated foods must be marked with this internationally recognized symbol • “treated with radiation, do not irradiate again” must be stated Genetic Modification • Selective Breeding • Recombinant DNA Technology ▫ DNA segment w/ desirable trait isolated ▫ Copies of segment spliced into traditional plant • GMO: ▫ DNA of food has been altered ▫ Purpose: resist herbicides & pesticides ▫ Benefits & harm greatly debated Pesticides • Protect against weeds, insects, fungi and increase crop yields • Insecticides, herbicides, fungicides • Can be natural or synthetic • Remain on foods • Who is especially sensitive? • EPA controls use of pesticides Growth Hormones • Recombinant bovine growth hormone (rBGH): genetically engineered & given to cows ▫ Increases muscle mass; decreases fat ▫ Increases milk output ▫ Causes mastitis in cows, resulting in __________________ ▫ methicillin-resistant Staphylococcus aureus (MRSA) develops Organic Foods • Conventional non-organic pesticides, insecticides, and herbicides are restricted • Livestock must be raised without the use of antibiotics or growth hormones • Cannot be genetically modified • Raised & harvested in an organic environment as approved and certified by the USDA