Lect22+Food+Safety - Food Safety !!Why should you care?...

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Unformatted text preview: Food Safety !!Why should you care? !!Do you like to travel? “Stomach Flu” If you ever had “stomach flu” with nausea, vomiting or diarrhea, you had food poisoning. What caused it? You may never know – too many possibilities When were you infected? Hours or up to 14 days previously What should you do? !!Types of organisms !!Probiotics !!How can you avoid bacteria (or worse things) in your food? food poisoning is hard to figure out what o rganism or what food it came from Food Poisoning/year •! 76 million Americans become sick each year (25% of population) •! 325,000 are hospitalized •! 5,000 die from food borne illness Short list of organisms causing food poisoning •! E. coli 0157:H7 and others •! Salmonella •! Norovirus •! Hepatitis A •! Campylobacter •! •! •! •! •! •! •! Giardia Cryptosporidium Cholera (Vibrio cholerae) Typhoid (Salmonella typhi) Parasites/worms Prions Natural products people with immunocompromise (cancer, aids) d ie from food borne illness What should you do? Avoid consuming food or water contaminated by feces •! e.g., meat, fish, shellfish, unpasteurized dairy, fruits, vegetables, grains •! usually uncooked, undercooked •! either in home or restaurant haiti: feces from the water avoid by not eating feces (major) •! Fecal: Sources of Contamination of Raw Food –! Animal slaughter –! Field conditions –! Poor hand washing practices –! Sewage contact •! Skin infections –! Poor hand washing practices 1 ! What should you do? •! WASH YOUR HANDS thoroughly after using the bathroom or changing diapers and before preparing or eating food. •! WASH YOUR HANDS after contact with animals or their environments (at farms, petting zoos, fairs, even your own backyard) •! COOK meats thoroughly. Ground beef and meat that has been needle-tenderized should be cooked to a temperature of at least 160°F/70˚C. It’s best to use a thermometer, as color is not a very reliable indicator of “doneness.” What should you do? •! AVOID raw milk, unpasteurized dairy products, and unpasteurized juices (like fresh apple cider). •! AVOID swallowing water when swimming or playing in lakes, ponds, streams, swimming pools, and backyard “kiddie” pools. •! PREVENT cross contamination in food preparation areas by thoroughly washing hands, counters, cutting boards, and utensils after they touch raw meat. raw milk: turberculosis (TB) Environment affects Health People moved out of cities to escape from "! slaughterhouses, tanneries "! raw sewage in streets "! lack of public sources of clean water "! Cholera, Typhoid "! 1793 Yellow Fever in Philadelphia "!George Washington & cabinet abandoned city "!More than 7% of population died Leading cause of food poisoning Microbes –! Can invade intestinal wall (infections) •! e.g. Salmonella, E. coli 0157:H7 –! Can produce toxins •! e.g. Staphylococcus aureus, Clostridium botulinum toxins are more dangerous Recent Food Poisoning •! History: In 1993, Jack in the Box undercooked hamburgers sickened 650 people, killed 4 children. •! 200 people sickened, 3 died from E. coli O157:H7 on raw spinach –! Spinach contaminated by feral pigs who tracked manure from beef ranch Norovirus Recently: 380 people sickened by Norovirus on 7 day Caribbean cruise 700 people sickened on cruise CDC estimates 23 million cases/year from norovirus 2 ! Typhoid Mary •! name Mary Mallon •! First known healthy carrier of typhoid (Salmonella typhi) •! Excreted bacteria in feces & urine •! Infected 47 people, 3 died •! Refused to cease working as a cook •! Signature dish: peaches & ice cream •! Forcibly quarantined twice Typhoid fever Typhoid fever: high fever, continuous headaches, diarrhea! Incidence of typhoid fever! ♦ Strongly endemic! ♦ Endemic! ♦ Sporadic cases! carried typhoid, but no symptoms spread typhoid. ASYMPTOMATIC CARRIER Cholera •! Kills 2,500,000 people annually •! 60% are children under age 5 •! Death possible in 3 hours Cholera •! Vibrio cholerae: secretes toxin •! Symptoms: severe diarrhea •! Treatment: Oral Rehydration Formula: glucose, sodium chloride, clean water –! E.g. Pedialyte; not Gatorade or apple juice (too much sugar – are hyperosmotic) causes water loss Cholera E. coli 0157:H7 •! Spinach, undercooked beef, unpasteurized milk or juice, contaminated water •! Severe bloody diarrhea, abdominal pain, vomiting •! 3 - 8% get Hemolytic uremic syndrome •! Other E. coli: “Traveler’s Diarrhea” montezuma's revenge 3 ! Eating out in places with questionable water supplies: "Boil it, cook it, peel it, or forget it. " Probiotics •! Will replacement or recolonization of GI tract prevent food poisoning? h igh immune system, or have caution Preventing Food borne Illness: Purchasing Food •! Promptly refrigerate or freeze foods when brought home •! Place meats in separate plastic bags •! Buy only pasteurized milk/cheese •! Avoid buying slimy, brownish produce •! •! •! •! •! Safe cooking practices Cook meats to designated temperatures Keep hot foods hot. Keep cold foods cold. Keep kitchen, hands, utensils CLEAN Avoid cross contamination!!! don't mix food unpasteurized: still births in preg. women hot foods hot, cold foods cold keep everything clean Preservation of Food: Prevents growth of bacteria •! Limit water available for bacteria: Salt, sugar, smoke, fermentation, drying •! Aseptic processing: Pasteurization, sterilization, irradiation •! Refrigeration, freezing, canning, chemical preservation •! Food Irradiation: 1963: wheat, potatoes; 1986: spices; 1990: poultry; 1997: beef Danger Zone: ! Between ! 40 - 135° F! irradiate potatoes so they don't sprout 4 ! Hepatitis A When in doubt, throw it out •! Symptoms: weakness, fatigue, jaundice, liver disease •! Appears 15 – 50 days after exposure •! Sources: unsafe food handling by carriers of the virus; raw or undercooked shellfish harvested from contaminated water •! Endures heat, cold, and drying •! Inactivated by cooking and irradiation life long disease, viral disease shellfish in contaminated water Prions •! Mad cow disease (bovine spongiform encephalopathy) •! Creurtzfeldt-Jakob disease •! Form of dementia •! FDA banned beef from Europe •! Ban on recycling animal tissues for animal feed Clostridium botulinum •! Causes botulism •! Spores survive in absence of air •! Common in honey or canned, low-acid foods Symptoms: depressed nerve function, paralysis, vomiting, abdominal pain, double vision, dizziness, respiratory failure Prevention: Avoid honey for infants under 1 year old; avoid dented, rusted, swollen cans don't eat food from dented cans toxin even if cooked, could get poisoned prevalent in honey for infants (adults have a cid) respitory failure Botulism •! The bacteria produce a TOXIN. •! Even if the bacteria are killed, the toxin is still very dangerous. •! Do NOT taste food if you suspect that it is contaminated. •! Botox!!! Campylobacter jejuni •! Very heat sensitive Sources: 90% of poultry tested positive •! Destroys the mucosal surfaces of small and large intestine Symptoms: intestinal inflammation, fever, muscle pain, headache, diarrhea (bloody) •! Treatment: antibiotics Prevention: prompt refrigeration, thorough cooking and hand washing FDA tests after food poisoning, very weak food p rotection system 5 ! Salmonella: Ingestion of live bacteria •! Killed by cooking •! Symptoms: nausea, fever, abdominal cramps, vomiting, diarrhea •! Sources: eggs, alfalfa sprouts, reptiles –! Greatest risk for cross contamination Escherichia coli " ! Found normally in the intestinal tract " ! Children and elderly are most at risk " ! Sources: food contaminated by fecal •! Treatment: fluids, rest •! Prevention: thorough hand washing, cleaning cutting boards, etc. material, ground beef " ! Symptoms: diarrhea, kidney failure, abdominal cramps " ! Prevention: Cook meat thoroughly S TAY HYDRATED. Apple juice is bad because o f high sugar. Natural Toxins •! •! •! •! •! •! •! Safrole from sassafras, mace, nutmeg Solanine from green potato skin Mushroom toxins Avidin in raw eggs Thiaminase in raw clams and mussels Oxalic acid in spinach, strawberries, etc. Senna and comfrey in herbal teas •! Cyanogenic glycosides from cassava can produce goiter and blindness Marine toxins Tetrodotoxin, saxitoxin: neurotoxins Sources: •!Puffer fish: very expensive delicacy accumulate tetrodotoxin •!Shellfish: accumulate saxitoxin from Red Tide Action: block sodium channels in nerves Symptoms: ascending paralysis, death Summary: Food Safety –! Practice personal hygiene –! Cook foods adequately –! Avoid cross-contamination –! Keep foods at safe temperatures –! Avoid foods from unsafe sources 6 ! ...
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